71 results on '"Kazemeini A"'
Search Results
2. Simulation of continuous catalytic conversion of glycerol into lactic acid in a microreactor system: A CFD study
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Pooya Jalal Sahandi, Samahe Sadjadi, and Mohammad Kazemeini
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chemistry.chemical_compound ,Biodiesel ,Materials science ,chemistry ,Chemical engineering ,General Chemical Engineering ,Yield (chemistry) ,Glycerol ,Mixing (process engineering) ,Micromixer ,Microreactor ,Catalysis ,Lactic acid - Abstract
Hand in hand with the flourish of the biodiesel industry, glycerol (GLY) as an inconvenient by-product has generated environmental and sustainability concerns. Devising measures for efficient transformation of GLY into value-added products is a promising solution. In this contribution, the transformation of GLY to lactic acid (LA) as a valuable chemical was investigated in a continuous process for industrial applications. In this regard, a catalytic method using heterogeneous Cu nanoparticles in NaOH solution was studied in a microreactor by a CFD simulation. A seven-inlet micromixer comprising an optimized mixing unit was incorporated for uniform distribution of the species. The effects of various parameters upon the process performance were considered and the optimum points were determined. Also, the extent of the influence of each variable on LA yield was evaluated using sensitivity analysis techniques. While higher LA yield could be obtained at extreme scenarios, optimum values of the Re and temperature for obtaining the maximum performance under sensible operating conditions were determined to be 0.108 and 510.1 K which led to the optimum yields of 67.8% and 59.5%, respectively. Moreover, the sensitivity analysis revealed that the molar ratio of OH−/GLY and temperature were the most and least significant parameters, respectively.
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- 2021
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3. Preparation of novel and highly active magnetic ternary structures (metal-organic framework/cobalt ferrite/graphene oxide) for effective visible-light-driven photocatalytic and photo-Fenton-like degradation of organic contaminants
- Author
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Seyed Behnam Bagherzadeh, Mohammad Kazemeini, and Niyaz Mohammad Mahmoodi
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Materials science ,Light ,Oxide ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,Ferric Compounds ,01 natural sciences ,Catalysis ,law.invention ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,law ,Fourier transform infrared spectroscopy ,Metal-Organic Frameworks ,chemistry.chemical_classification ,Graphene ,Cobalt ,Electron acceptor ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,Photocatalysis ,Graphite ,0210 nano-technology ,Ternary operation ,Visible spectrum ,Nuclear chemistry - Abstract
Herein, MIL-101(Fe), CoFe2O4, novel binary (MIL-101(Fe)/CoFe2O4, MIL-101(Fe)/GO and CoFe2O4/GO), and ternary (MIL-101(Fe)/CoFe2O4/(3%)GO and MIL-101(Fe)/CoFe2O4/(7%)GO) magnetic composites based upon the MIL-101(Fe) were synthesized. The XRD, FESEM, TEM, EDX, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses were applied to characterize samples. The MIL/CoFe2O4/(3%)GO demonstrated the best performance compared to other samples for visible light photocatalytic and photo-Fenton-like degradation of Direct Red 23 (DtR-23), Reactive Red 198 (ReR-198) dyes as well as Tetracycline Hydrochloride (TC-H) antibiotic. Degradation of dyes using the ternary composite after 70 min of visible light irradiation was greater than that of 99%. The presence of the optimum GO as a strong electron acceptor in MIL/CoFe2O4/(3%)GO not only led to the effective separation of charge carriers and thus reduction of their recombination but also increased the absorption of visible light. The composite possessed good durability in terms of stability and reusability. The PL, EIS and electrochemical analyses indicated that the MIL/CoFe2O4/(3%)GO improved the optical properties and photocatalytic performance.
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- 2021
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4. Influence of metal loading and reduction temperature on the performance of mesoporous NiO–MgO–SiO2 catalyst in propane steam reforming
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Fatola Farhadi, Masoud Rezaei, Mohammad Kazemeini, A. Keshavarz, and F. Barzegari
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inorganic chemicals ,Materials science ,020209 energy ,chemistry.chemical_element ,02 engineering and technology ,Catalysis ,Metal ,Steam reforming ,Nickel ,chemistry.chemical_compound ,020401 chemical engineering ,chemistry ,Chemical engineering ,Propane ,visual_art ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,0204 chemical engineering ,Mesoporous material ,Dispersion (chemistry) ,Carbon - Abstract
In this research, a series of NiO–MgO–SiO2 catalyst samples with various nickel contents (5, 10, 15 and 20 wt %) were prepared by a co-precipitation method followed by a hydrothermal treatment and employed in propane steam reforming. The analyses revealed that the enhancement of the nickel content up to 15 wt % improved the propane conversion to 98.6% at 550 °C. Nonetheless, further increase in the nickel loading reduced the catalyst activity due to the formation of larger and more poorly dispersed active sites. Besides, 15 wt % nickel loading led to the high resistance against coke deposition with no detectable carbon on the catalyst surface. In addition, it was revealed that, the decrease in steam to carbon (S/C) ratio caused further carbon depositions upon the catalyst surface as well as producing higher extents of undesired by-products. Besides, results proved that the alternation of reduction temperature within 500–650 °C caused a significant influence on the dispersion and particle size of metallic Ni. The accessible metallic Ni for reactants and consequently catalyst performance was strongly affected by reduction temperature. The results exhibited that the reduced catalyst at 550 °C possessed the highest activity with the lowest amount of by-products owning to the formation of highly dispersed small Ni species. Higher reduction temperatures accelerated the agglomeration of Ni species, which negatively affected the catalytic performance.
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- 2021
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5. Renewable hydrogen production by aqueous-phase reforming of Glycerol using Ni/Al2O3-MgO nano-catalyst: effect of the Ni loading
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Mohammad Kazemeini and Farzad Bastan
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Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Aqueous two-phase system ,chemistry.chemical_element ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Vaporization ,0202 electrical engineering, electronic engineering, information engineering ,Glycerol ,Molecule ,Selectivity ,0105 earth and related environmental sciences ,Nuclear chemistry ,Hydrogen production - Abstract
Aqueous-phase reforming (APR) of oxygenated hydrocarbons for hydrogen production presents several advantages as feed molecules might be easily found in a wide range of biomass; there is no need for its vaporization and the process allows thorough exploitation of the environmental benefits of using hydrogen as an energy carrier. In this contribution, catalysts with active phase Ni supported on Al2O3-MgO were synthesized at different loadings (1, 3, 5, 7, and 10 wt%) through the co-precipitation technique and tested for the Glycerol APR reaction. Effects of the Ni loading on physicochemical characteristics of Ni/Al2O3-MgO catalysts were examined. Moreover, catalytic performance was investigated in order to determine the optimum catalyst for H2 production in APR of Glycerol. The catalysts were characterized by the XRD, BET-BJH, TPR, and TEM analyses. The reaction was carried out in a fixed-bed reactor with solution of 10 wt% Glycerol at 250 °C and 50 bar. Results revealed that the APR activity of synthesized catalysts strongly depended on the Ni loading. In addition, it was considered a foregone conclusion that, among the synthesized catalysts, catalytic activity increased through enhancement of the Ni loading up to 5 wt%. Furthermore, the 5 wt% Ni/Al2O3-MgO nano-catalyst possessed highest catalytic activity of 92% total conversion and selectivity towards hydrogen production of 76%. It was concluded that the APR activity lowered in the following order: 5 > 3 > 1 > 7 > 10 wt% Ni/Al2O3-MgO.
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- 2020
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6. Propane steam reforming on mesoporous NiO–MgO–SiO2 catalysts for syngas production: Effect of the MgO/SiO2 molar ratio
- Author
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Fatola Farhadi, Masoud Rezaei, Mohammad Kazemeini, A. Keshavarz, and F. Barzegari
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Materials science ,Renewable Energy, Sustainability and the Environment ,Precipitation (chemistry) ,Energy Engineering and Power Technology ,Coke ,Condensed Matter Physics ,Catalysis ,Steam reforming ,chemistry.chemical_compound ,Fuel Technology ,Chemical engineering ,chemistry ,Propane ,Mesoporous material ,Hydrogen production ,Syngas - Abstract
In this research, a series of NiO-xMgO-SiO2 catalysts with various MgO/SiO2 molar ratios were prepared via precipitation method followed by a hydrothermal treatment in the presence of PVP as surfactant. The synergic effect between MgO and SiO2 leading to the various characteristic and catalytic performance during propane steam reforming was investigated in detail. The results showed that 15 wt% NiO-0.5MgO–SiO2 catalyst possessed the highest catalytic activity (68.9% conversion for C3H8 at 550 °C) with a negligible amount of carbon formation after 20 h of reaction duration. This superior catalytic performance can be attributed to the enhanced basicity strength along with strong metal-support interaction due to the formation of NiO–MgO solid solution, as confirmed by CO2-TPD and TPR analyses, respectively. In addition, the maximum hydrogen yield was obtained through the NiO–MgO sample because of higher progress in other hydrogen production routes as opposed to that of the propane steam reforming. It also can be suggested that relatively weak interaction between active sites and support was probably the main reason for unstable catalytic behavior of NiO–SiO2 sample with the lowest activity. This study confirms that the appropriate MgO/SiO2 ratio led to the sufficient metal-support interaction and delicate balance between acidic/basic sites, which was followed by the great activity, and coke resistance during PSR.
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- 2020
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7. Preparation of mesoporous nanostructure NiO–MgO–SiO2 catalysts for syngas production via propane steam reforming
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F. Barzegari, Mohammad Kazemeini, Fatola Farhadi, Masoud Rezaei, and A. Keshavarz
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Materials science ,Renewable Energy, Sustainability and the Environment ,Non-blocking I/O ,Energy Engineering and Power Technology ,02 engineering and technology ,Coke ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Steam reforming ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Chemical engineering ,law ,Propane ,Calcination ,0210 nano-technology ,Mesoporous material ,Syngas - Abstract
In this research, the propane steam reforming (PSR) as a promising alternative route over a mesoporous NiO–MgO–SiO2 catalyst to produce syngas (SG) was undertaken. This catalyst was prepared using a co-precipitation method followed by hydrothermal treatment. The influence of such catalyst preparation factors as the hydrothermal time and temperature, pH and calcination temperature on the physicochemical characteristics of the prepared samples were examined. Next, these materials were characterized through the BET-BJH, XRD, TPR, and FTIR analyses. The thermal stability of this catalyst was tested through the TGA and DTA techniques. Furthermore, the deactivation of the calcined catalysts at different temperatures was investigated via the TPO analysis. The utilized synthesis method led to preparation of a species with a mesoporous structure possessing a rather high surface area of 741 m2g-1. The catalyst performance at a reaction temperature of 550 °C revealed that, the increment in calcination temperature from 500 to 800 °C led to lowering of the propane conversion as well as the hydrogen yield from 65 to 37.4% and 39.4 to 22.6%, respectively. Meanwhile, the extent of the deposited coke upon the catalyst surface was reduced when implementing the higher calcination temperature. This was attributed to high amounts of the NiO, which was included in the solid solution containing the MgO–SiO2 support. In other words, the isolation of Ni2+ with Mg2+ species and strong interaction between NiO and MgO decreased the NiO particle size hence, its reducibility. These in turn led to the formation of smaller active sites possessing higher deactivation resistance against sintering and coke deposition. Thus, a highly active and stable catalyst was developed.
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- 2020
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8. Developing a mathematical model for reforming of glycerol towards a comparative evaluation of the liquid vs. gas phase medium
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Zahra Nayernia, Afsanehsadat Larimi, and Mohammad Kazemeini
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Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Steam reforming ,Crystallinity ,chemistry.chemical_compound ,Fuel Technology ,Chemical engineering ,chemistry ,Catalytic reforming ,Glycerol ,Particle size ,0210 nano-technology ,BET theory - Abstract
Glycerol might be converted into hydrogen through a catalytic reforming process. In order to design an effective route, the choice of reaction conditions and in particular its medium considered yet a crucial issue still needing further investigations. In this research, a mathematical model of reforming processes in vapor (i.e., steam reforming (SR) and liquid phase (i.e.; aqueous phase reforming (APR)) were developed. This was performed in terms of understudying effects of parameters including the reactor diameter, catalyst morphology (i.e., particle size) and mass flow rate on the glycerol conversion. Then, a superior reaction medium in terms of these variables was determined. For data validation, experimental values were adopted from glycerol reforming over Pt/CeZrO2 catalyst with BET surface area of 81–102 m2 g−1, mean particle size of 5.29–7.18 nm and crystallinity of 40–53%. It was revealed that, for the same WHSV and reactor length, conversion of the APR was considerably more than that of the SR process. Moreover, it was demonstrated that, if the SR had to have the same conversion as that of the APR, the utilized reactor length should have approximately increased by about 80 folds for the liquid phase. Overall, this study provided a simple pathway through the developed model to comparatively evaluate the medium (i.e.; gaseous as in the SR vs. liquid as in the APR) for the glycerol conversion aiming at reducing experimental costs a head of going to the laboratory.
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- 2019
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9. Effect of rare-earth promoters (Ce, La, Y and Zr) on the catalytic performance of NiO-MgO-SiO2 catalyst in propane dry reforming
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F. Barzegari, M. Rezaei, M. Kazemeini, F. Farhadi, and A.R. Keshavarz
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Process Chemistry and Technology ,Physical and Theoretical Chemistry ,Catalysis - Published
- 2022
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10. Improved H2 production from the APR of polyols in a microreactor utilizing Pt supported on a CeO2Al2O3 structured catalyst
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Mohammad Kazemeini and Behzad Entezary
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Materials science ,Renewable Energy, Sustainability and the Environment ,Aqueous two-phase system ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Chemical engineering ,Glycerol ,Microreactor ,0210 nano-technology ,Selectivity ,Platinum ,Ethylene glycol ,Hydrogen production - Abstract
In this research, the activity and selectivity of a platinum-based catalyst for H2 production through aqueous phase reforming (APR) in a fixed-bed reactor (FBR) as well as, a structured catalyst microreactor (MR) were investigated. In this venue, first, an in-house designed MR was fabricated and the catalytic material was deposited on the channel walls of this steel made reactor. After verification of the stability of the coated layer, the prepared reactor was employed to investigate the APR reaction. In this regard, APR of the ethylene glycol and glycerol over Pt/Al2O3 and Pt/CeO2 Al2O3 catalyst were conducted in an MR and FBR. Obtained results demonstrated that employing Pt/CeO2 Al2O3 as a highly active catalyst in an FBR, slightly reduced the H2 selectivity for the APR reaction of the ethylene glycol. Moreover, this effect appeared even more pronounced in reforming of glycerol. On the other hand, utilization of an MR for the APR of glycerol improved the H2 selectivity due to the more active Pt/CeO2 Al2O3 catalyst, for this process. Comparison of the results revealed that the highly active catalyst alongside a reactor alleviating mass transfer limitations were two complementary factors leading to better performance of such chemical systems. Moreover, this research emphasized that obtained values of the APR conversion and H2 selectivity in an MR coated with the Pt/CeO2 Al2O3 catalyst was superior to those obtained from an FBR. Ultimately, the best results obtained for the aforementioned catalytic species indicated that the APR of glycerol in a structured catalyst MR led to 75.3% conversion of glycerol and 92.4% selectivity to hydrogen production both of which were considerably better than results determined in an FBR.
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- 2018
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11. Production of renewable hydrogen through aqueous-phase reforming of glycerol over Ni/Al2O3MgO nano-catalyst
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Farzad Bastan, Afsanehsadat Larimi, Hesam Maleki, and Mohammad Kazemeini
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Hydrogen ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Aqueous two-phase system ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Glycerol ,Mixed oxide ,Nano catalyst ,0210 nano-technology ,Selectivity ,Hydrogen production ,Nuclear chemistry - Abstract
In this study, a series of Ni nano-catalysts supported on Al2O3 and MgO were prepared through the co-precipitation technique. Effects of the Al/Mg ratio on physicochemical characteristics of Ni/Al2O3 MgO catalysts were examined. Moreover, catalytic performance was investigated in order to determine the optimum catalyst for H2 production in aqueous phase reforming (APR) of glycerol. It was revealed that, the APR activity of synthesized catalysts strongly depended on the aforementioned ratio. In addition, it was observed that, the catalytic activity of Ni/MgO and Ni/Al2O3 samples were both lower than that of the corresponding mixed oxide supports. Furthermore, it was shown that, amongst the compositionally different prepared mixed oxide materials, the respective catalytic activities increased through enhancing of the Al/Mg ratio. It was demonstrated that the Ni/Al2Mg1 catalyst possessed highest catalytic activity of 92% glycerol conversion and selectivity towards hydrogen production of 76%. Ultimately, it was concluded that, the APR activity lowered in the following order: Ni/Al2Mg1 > Ni/Al1Mg1 > Ni/Al1Mg2 > Ni/Al > Ni/Mg for the understudied synthesized materials.
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- 2018
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12. Oxidative desulfurization of a model liquid fuel over an rGO-supported transition metal modified WO3 catalyst: Experimental and theoretical studies
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Alimorad Rashidi, Saeed Hasannia, Mohammad Kazemeini, and Abdolvahab Seif
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Materials science ,Substrate (chemistry) ,Filtration and Separation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Analytical Chemistry ,Flue-gas desulfurization ,Catalysis ,Liquid fuel ,Chalcogen ,chemistry.chemical_compound ,020401 chemical engineering ,Transition metal ,chemistry ,Chemical engineering ,Impurity ,Dibenzothiophene ,0204 chemical engineering ,0210 nano-technology - Abstract
The XW/rGO compounds (XW = Co or Ni modified WO3) have has been utilized as catalysts in the oxidative desulfurization (ODS) process of a liquid model fuel containing dibenzothiophene (DBT). Various characterization methods were carried out to complete evaluations of the prepared catalysts. Moreover, using the GC–MS method, it became clear that the final product of the process was dibenzothiophene sulfone (DBTO2). Furthermore, results showed that under the optimized conditions (oxidant to substrate molar ratio = 6, 75 °C and catalyst to substrate molar ratio = 0.08), the DBT content of a model fuel was declined by 100% only within a reaction duration time of 45 min using the CoW (20)/rGO catalyst. Also, the results obtained from the DFT study revealed that, for an efficient reaction over the surface of the catalyst, along with the S⋯O chalcogen interaction, the strength of the H-bonds interactions (H⋯O) between the DBT and active sites on catalysts may have tuned-up the driving force of the reaction. Ultimately, the results indicated that the charge transfer at the XW/rGO interface may be tuned by selecting impurity used alongside the WO3 species.
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- 2021
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13. Optimizing parameters affecting synthesis of a novel Co–Mo/GO catalyst in a Naphtha HDS reaction utilizing D-optimal experimental design method
- Author
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Saeed Soltanali, Mohammad Kazemeini, Alimorad Rashidi, and Zeinab Hajjar
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Materials science ,010405 organic chemistry ,Thermal desorption spectroscopy ,Graphene ,General Chemical Engineering ,Prepared Material ,Oxide ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Organic chemistry ,Graphite ,0210 nano-technology ,Naphtha ,Incipient wetness impregnation - Abstract
In this research effects of important synthesis parameters upon catalytic performance of a novel graphene based catalyst for an HDS reaction were investigated. The graphene oxide (GO) used as a support was initially prepared through chemical exfoliation of graphite via modified Hummers method. In this venue the impregnation method, promoter/main metallic spices ratio, total metal loading of the active phase and amount of chelating agent were systematically understudied. Thus, GO was impregnated with active metallic phases through the hydrothermal and modified incipient wetness impregnation techniques. In both procedures, 1:2, 1:3 and 1:4 weight ratios of Co/Mo with the percentages of the total metals amounting to 5, 10, and 15, respectively, were utilized. This was done together with the citric acid (CA) as a chelating agent with a CA/Mo molar ratio varying in the range of 1–5. The synthesized materials were characterized through the X-ray diffraction (XRD) technique as well as; the BET–BJH surface area measurements, Field Emission Scanning Electron Microscopy (FESEM), Inductively Coupled Plasma (ICP) and Temperature programmed desorption of ammonia (NH3-TPD) analyses. After a thorough characterization of this material, the catalyst was evaluated in an HDS reaction through a fixed-bed reactor under industrial conditions for a Naphtha feed. Obtained results revealed 95–100% conversions. This rendered the prepared material very promising for the purpose at hand. Then the D -optimal experimental design software was utilized to optimize the preparation of the GO based catalysts. In this venue, although the hydrothermally prepared material provided a more economical catalyst, the wetness impregnation method prevailed as the preferred one to synthesize an optimum catalyst with 0.3 wt% Co/Mo ratio, 10% total metal loadings and CA/Mo molar ratio of 2.
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- 2017
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14. Aqueous-phase reforming of glycerol for production of alkanes over Ni/CexZr1-xO2 nano-catalyst: Effects of the support’s composition
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Farzad Bastan, Mohammad Kazemeini, and Afsanehsadat Larimi
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Alkane ,chemistry.chemical_classification ,Renewable Energy, Sustainability and the Environment ,Chemistry ,020209 energy ,Inorganic chemistry ,Aqueous two-phase system ,02 engineering and technology ,Catalysis ,chemistry.chemical_compound ,0202 electrical engineering, electronic engineering, information engineering ,Glycerol ,Reactivity (chemistry) ,Selectivity ,Dispersion (chemistry) ,BET theory ,Nuclear chemistry - Abstract
The aqueous phase reforming (APR) reaction of glycerol considered to be environmentally green. It converted polyols into value added products including; H2 and alkanes. Ni species known for its capability of producing alkane-rich gas under the APR process conditions might be utilized for this purpose. In this research, the conversion of glycerol into alkanes demonstrated using 10wt% Ni/CexZr1-xO2 (with x = 0, 0.3, 0.5, 0.7 and 1) catalysts. In order to better understand the behavior of these materials, they were evaluated physio-chemically through the; XRD, BET, H2-TPR, H2-Chemisorption and TEM analyses. Moreover; performances of the synthesized materials were determined through their reactivity. Results revealed that, this variable depended strongly upon the Ce/Zr ratio in turn affecting the active metal dispersion, BET surface area and particle size distribution of prepared species. Amongst catalysts prepared, an optimum one with composition of 10wt% Ni/Ce0.3Zr0.7O2 was pinpointed. This showed the highest carbon content in the gaseous product (99%), highest alkane selectivity (40%) as well as; a minimum of 25 h of stability. Ultimately, it was concluded that, the overall catalytic performance of the prepared materials lowered in the following order: Ni/Ce0.3Zr0.7O2 > Ni/Ce0.5Zr0.5O2 > Ni/Ce0.7Zr0.3O2 > Ni/ZrO2 > Ni/CeO2.
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- 2017
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15. Transesterification of canola oil over Li/Ca-La mixed oxide catalyst: Kinetics and calcination temperature investigations
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Mohammad Kazemeini and Hesam Maleki
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020209 energy ,Inorganic chemistry ,02 engineering and technology ,Transesterification ,Heterogeneous catalysis ,Catalysis ,law.invention ,Thermogravimetry ,chemistry.chemical_compound ,chemistry ,law ,0202 electrical engineering, electronic engineering, information engineering ,Mixed oxide ,Calcination ,Methanol ,Fourier transform infrared spectroscopy ,Nuclear chemistry - Abstract
In this research, a solid 1%Li/Ca-La mixed oxide catalyst was prepared using co-precipitation method followed by wet impregnation. The prepared catalyst was used in the transesterification reaction of canola oil and methanol for biodiesel synthesis. The effects of calcination and reaction temperatures were investigated on the activity of the catalyst. In addition, rate of the reaction was studied through a kinetic model for which parameters were determined. Surface properties and structure of the catalyst were characterized through the powder X-ray diffraction (XRD), thermogravimetry/derivative thermogravimetry (TG/DTG), and Fourier transform infrared spectroscopy analysis. All these emphasized that the performance of the catalyst corresponded to the generation of the active sites and their thermal activation.
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- 2017
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16. Transesterification of canola oil and methanol by lithium impregnated CaO–La 2 O 3 mixed oxide for biodiesel synthesis
- Author
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Hesam Maleki, Afsaneh S. Larimi, Farhad Khorasheh, and Mohammad Kazemeini
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Biodiesel ,Materials science ,020209 energy ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,Transesterification ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,Catalysis ,chemistry.chemical_compound ,chemistry ,Biodiesel production ,0202 electrical engineering, electronic engineering, information engineering ,Organic chemistry ,Mixed oxide ,Lithium ,Methanol ,0210 nano-technology ,Nuclear chemistry - Abstract
CaO–La2O3 mixed oxides were synthesized by co-precipitation coupled with Li doping through wet impregnation. These were used as catalysts for transesterification of canola oil and methanol toward biodiesel production. To determine the structure and morphology of the prepared catalysts, they were characterized by the XRD, FESEM, BET, and basic strength measurements. Under optimum reaction conditions of methanol/oil molar ratio of 15:1, 5 wt% catalyst at 65 °C, 96.3% conversion was obtained in 2.5 h of reaction duration. Moreover, the catalyst demonstrated a rather high stability where reuse of up to five cycles without significant loss of performance observed.
- Published
- 2017
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17. Naphtha HDS over Co-Mo/Graphene catalyst synthesized through the spray pyrolysis technique
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Alimorad Rashidi, Farzad Bahadoran, Saeed Soltanali, Zeinab Hajjar, and Mohammad Kazemeini
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Chemistry ,Graphene ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,01 natural sciences ,Sulfur ,0104 chemical sciences ,Analytical Chemistry ,Catalysis ,law.invention ,Fuel Technology ,Chemical engineering ,law ,Organic chemistry ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Pyrolysis ,Naphtha ,Hydrodesulfurization - Abstract
Co-Mo/Graphene composite synthesized for the first time through the spray pyrolysis method and applied as an HDS catalyst to produce a sulfur free Naphtha feed. The major advantage of the spray pyrolysis technique was its concurrent capability of the in-situ and simultaneous Co-Mo deposition upon the graphene. The produced material was characterized through the XRD, BET-BJH, FTIR and Raman spectroscopy as well as; the NH 3 -TPD, TPR, TEM and FESEM techniques. The prepared catalyst showed unique properties such as; high degree of total acidity of 5.1 (vs. the usual 0.2–2.0) mmole NH 3 /g-cat and a relatively high surface area of 705 vs. 189 m 2 /g of the commercial material. Furthermore, the synthesized graphene based material reduced to active species considerably easier than that of the alumina based commercial catalyst. Ultimately, the HDS reactor evaluation of the prepared composite catalyst over a Naphtha feed of 2800 ppm total sulfur (for all practical purposes) displayed 100% sulfur removal while only 91.07% conversion obtained over a commercial industrial catalyst.
- Published
- 2017
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18. An electrochemical energy conversion realized through Ag@Pt/rGO nano-catalyst enhancing activity of the ORR process in a PEMFC
- Author
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Ali Esfandiari and Mohammad Kazemeini
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Materials science ,Chemical engineering ,Graphene ,law ,General Engineering ,Proton exchange membrane fuel cell ,Cyclic voltammetry ,High-resolution transmission electron microscopy ,Electrocatalyst ,Electrochemistry ,Electrochemical energy conversion ,law.invention ,Catalysis - Abstract
Core-Shell structures of Ag@Pt nanoparticles (NPs) dispersed upon reduced graphene oxide (rGO) support containing different Ag:Pt mass ratios synthesized through the ultrasonic treatment method. These applied to the oxygen reduction reaction (ORR) process in a Proton Exchange Membrane Fuel Cell (PEMFC). The morphology of as-prepared catalysts characterized through High Resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and induced coupled plasma atomic emission spectroscopy (ICP-OES) analyses. The ORR activities and stabilities of catalysts studied through electrochemical measurements of Cyclic Voltammetry (CV) and single cell tests, respectively. The results revealed, prepared Ag@Pt/rGO catalysts possessed a Core-Shell nanostructure and the one with the Ag:Pt mass ratio of 1:3 displayed the largest electrochemical surface area (of 77.6 m2 g-1) as well as; provided the highest stability compared with prepared electrodes containing other Ag:Pt ratios and the obtained commercial Pt/C material. The maximum power density for the MEA prepared with this electrocatalyst determined to be 55% higher than that of the commercial Pt/C evaluated through single cell techniques. Thus, the understudied material seemed to be a very promising cathode for utilizing in PEM fuel cells.
- Published
- 2019
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19. Nanocomposite of functionalized halloysite and Ag(0) decorated magnetic carbon dots as a reusable catalyst for reduction of dyes in water
- Author
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Samahe Sadjadi, Mostafa Latifi pour, and Mohammad Kazemeini
- Subjects
Materials science ,Nanocomposite ,Composite number ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Halloysite ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Rhodamine B ,engineering ,Methyl orange ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Melamine - Abstract
A new magnetic, catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This new composite was characterized through the XRD, TEM, BET, FTIR, TGA, EDX, and mapping analyses. The catalytic experiments confirmed that low loadings of the Hal-MT-Cys-Ag/MNCD composite reduction of both dyes were performed in ~1 min. This material could also be readily collected from the reaction media magnetically and displayed excellent recyclability with a slight decrease in its activity of at most ~6% up to 8 cycles. The kinetic and thermodynamic study of de-colorization reactions emphasized high catalytic performances of the synthesized nanocomposite. More precisely, activation energy, enthalpy, and entropy were determined to be 48.15 kJ mol−1, 45.65 kJ mol−1, and -124.61 J mol−1 K−1; respectively for the methyl orange while the corresponding values for the rhodamine B were found to be 11.03 kJ mol−1, 8.53 kJ mol−1, and -249.93 J mol−1. K−1.
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- 2021
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20. The Influence of Lanthanide on NiO-MgO-SiO2 Catalysts for Syngas Production via Propane Steam Reforming
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Fatola Farhadi, A. Keshavarz, Masoud Rezaei, Mohammad Kazemeini, and F. Barzegari
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Lanthanide ,010405 organic chemistry ,Process Chemistry and Technology ,Coke ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Metal ,Steam reforming ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Propane ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Syngas - Abstract
In this study, 15 wt. % NiO-MgO-SiO2 catalysts modified by La2O3 promoter were prepared through a co-precipitation route and employed for syngas production via propane steam reforming. Various techniques including X-Ray diffraction, BET, TPR, CO2-TPD, CO-chemisorption, TPO, and Scanning electron microscopy were utilized to characterize the final samples. The results indicated that the incorporation of La2O3 enhanced the metal-support interaction providing less reducible Ni species. In comparison with the La-free catalyst, the promoted ones possessed higher metal dispersion and smaller Ni particles. Nonetheless, excessive amounts of La covering the active sites negatively decreased the Ni dispersion and corresponding surface area. In addition, upon the introduction of La2O3 the strength and amount of strong basic sites enhanced owing to the preferential adsorption of CO2 on La2O3. The evaluation of the catalytic performance disclosed that despite the improved metal dispersion, the promoted catalysts possessed lower propane conversion and hydrogen yield than the un-promoted one. It might be attributed to the decrease in the acidic sites which contributed to CHx decomposition. Nevertheless, the highest activity was achieved with 3 wt. % La2O3 loading which was induced by highly dispersed metallic Ni and more accessible active sites for adsorption and dissociation. It was also confirmed that, the existence of La2O3 improved the resistance against coke formation owning to the formation of well-dispersed Ni species and acceleration of gasification reaction through the La2O2CO3.
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- 2021
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21. Copper oxide-carbon nanotube (CuO/CNT) nanocomposite: Synthesis and photocatalytic dye degradation from colored textile wastewater
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Cyrus Ghotbei, Niyaz Mohammad Mahmoodi, Pardis Rezaei, and Mohammad Kazemeini
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Copper oxide ,Nanocomposite ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Photocatalysis ,Degradation (geology) ,Fourier transform infrared spectroscopy ,Composite material ,0210 nano-technology ,Photodegradation - Abstract
In this paper, CuO/CNT nanocomposite was synthesized and its photocatalytic dye degradation ability for colored textile wastewater was studied. The characteristics of the nanocomposite were investigated by XRD, SEM and FTIR. The photodegradation of Direct Red 31 (DR31) and Reactive Red 120 (RR120) by CuO/CNT in presence of H2O2 was investigated. Photocatalytic dye degradation was determined by UV-vis spectrophotometer. Effects of catalyst dosage, initial dye concentration and salt on photodegradation performance were studied. The photocatalytic dye degradation ability of pure CuO and CuO/CNT nanocomposite is 78 % and 89 % for DR31 and 70 % and 87 % for RR120, respectively. The results showed that CNT increased the photocatalytic activity of CuO. The presence of salt decreases dye degradation efficiency. The dye degradation kinetics by nanocomposite followed first-order kinetic model. The reaction rate at 0.005 g catalyst was 0.0137 and 0.0105 min-1 for DR31 and RR120, respectively. It was found that the CuO/CNT nanocomposite as a photocatalyst could be used to degrade dyes from colored wastewater.
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- 2016
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22. Highly selective doped PtMgO nano-sheets for renewable hydrogen production from APR of glycerol
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Farhad Khorasheh, Afsanehsadat Larimi, and Mohammad Kazemeini
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Materials science ,Dopant ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,Doping ,Aqueous two-phase system ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Chemisorption ,Nano sheets ,Glycerol ,0210 nano-technology ,Hydrogen production - Abstract
A series of M-doped Pt MgO (M = Pd, Ir, Re, Ru, Rh and Cr) sheet-shaped nano-catalysts were synthesized by the controlled co-precipitation method. The effects of M-doping on both the physicochemical and the chemisorption characteristics of Pt MgO catalysts were examined. The performance of the catalysts for the aqueous phase reforming (APR) of glycerol was also investigated. The APR activity of Pt M MgO catalysts depended on the type of the M dopant used. The APR activity varied in the following order: Rh > Pd > Cr > Ir > undoped ≈ Ru > Re, with the Rh-promoted catalyst having an activity of about one order of magnitude higher than the Re-promoted catalyst at 250 °C. It was found that M-promotion had a significant effect on the reducibility of the Pt MgO catalysts thus affecting their APR activity.
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- 2016
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23. Aqueous phase reforming of glycerol using highly active and stable Pt0.05CexZr0.95-xO2 ternary solid solution catalysts
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Farhad Khorasheh, Mohammad Kazemeini, and Afsanehsadat Larimi
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Hydrogen ,Chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Metal ,X-ray photoelectron spectroscopy ,Oxidation state ,visual_art ,visual_art.visual_art_medium ,Reactivity (chemistry) ,0210 nano-technology ,Selectivity ,Solid solution - Abstract
The aqueous phase reforming (APR) of glycerol is an attractive yet challenging pathway to convert abundant biomass into value added hydrogen. Pt catalysts have received attention due to their ability to produce hydrogen-rich gas under APR conditions. In this work, the conversion of glycerol into hydrogen is demonstrated using Pt 0.05 Ce x Zr 0.95-x O 2 (x = 0, 0.29, 0.475, 0.66 and 0.95) solid solution catalysts. Both characteristic (XRD, BET, H 2 -TPR, CO-chemisorption, TEM and XPS) and reactivity measurements were used to investigate the activity of the catalysts. Results indicated that reactivity depended on the Ce/Zr ratio, which in turn affected the Pt oxidation state, active metal dispersion and surface area, and particle size. Among these catalysts Pt 0.05 Ce 0.475 Zr 0.475 O 2 showed the highest carbon to gas conversion (95%), highest H 2 yield (93%), highest H 2 selectivity (98%) and at least 50 h of stability. The overall catalytic performance decreased in the order Pt 0.05 Ce 0.475 Zr 0.475 O 2 > Pt 0.05 Ce 0.29 Zr 0.66 O 2 > Pt 0.05 Zr 0.95 O 2 > Pt 0.05 Ce 0.66 Zr 0.29 O 2 > Pt 0.05 Ce 0.95 O 2 .
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- 2016
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24. Oxidation of H2S to Elemental Sulfur over Alumina Based Nanocatalysts: Synthesis and Physiochemical Evaluations
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Mohammad Rezaee, Leila Vafajoo, Mohammad Kazemeini, Moslem Fattahi, and Alimorad Rashidi
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Materials science ,Sodium oxide ,Inorganic chemistry ,General Engineering ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Sulfur ,Nanomaterial-based catalyst ,0104 chemical sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Titanium dioxide ,0210 nano-technology ,Space velocity - Abstract
In this paper oxidation of the H2S into elemental sulfur over synthesized alumina-based nanocatalysts was physiochemically investigated and the results compared with a commercial Claus catalyst. The wet chemical, co-precipitation and spray pyrolysis techniques employed to synthesize several alumina nanostructures. Then, the SEM, XRD and ASAP analysis methods utilized to characterize in order to choose the best nanocatalyst. The sulfur andH2S contents determined through the standard UOP techniques. Amongst these as-synthesized materials, Al2O3-supported sodium oxide prepared through the wet chemical and Al2O3 nanocatalyst via spray pyrolysis methods were the most active catalysts for the purpose at hand. In addition, the titanium dioxide nanostructure and a hybrid of nano alumina support (made via the wet chemical method) decorated on the carbon nanotube prepared for this goal. Moreover, the statistical design of experiments screening of the significant synthesizing parameters performed through the Box-Behnken (e.g.;Response Surface Methodology (RSM)) technique. Ultimately, the best chemically characterized nanocatalyst was subjected to evaluations in a fixed bed reactor while effects of temperature, metal loading and GHSV understudied. It was observed that, the alumina nanoparticles prepared through the wet chemical and spray pyrolysis methods led H2S into elemental sulfur in a reproducible manner with 97 and 98% conversions, respectively. Both of these were more desirable than that obtained utilizing the commercial catalysts (i.e.: CR-3S and CRS-31) providing nearly 96% conversion.
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- 2016
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25. Physicochemical Properties and Catalytic Performances of Nanostructured V2O5 over TiO2 and γ-Al2O3 for Oxidative Dehydrogenation of Propane
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Moslem Fattahi, M. Nikkhah, Mohammad Kazemeini, and Leila Vafajoo
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Nanostructure ,Process Chemistry and Technology ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,Oxidative phosphorylation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Catalysis ,Volumetric flow rate ,chemistry.chemical_compound ,chemistry ,Propane ,Molar ratio ,oxidative dehydrogenation ,nanostructure ,V2O5 ,hydrothermal method ,TiO2/Al2O3 ,Dehydrogenation ,0210 nano-technology ,Selectivity - Abstract
Samples of V2O5 catalysts supported on nanostructures of TiO2 and γ-Al2O3 were synthesized through the hydrothermal method and used for the oxidative dehydrogenation of propane (ODHP) to propylene. The TiO2 support was utilized in both commercial microstructure and synthesized nanostructure forms. Moreover, the γ-Al2O3 support was synthesized through chemical and precipitation methods. The vanadium catalyst was then deposited onto the hybrid of the TiO2 and γ-Al2O3 materials. All prepared catalysts were characterized through the BET, FESEM, FTIR, XRD and TPR techniques. Performances of the synthesized catalysts were subsequently examined in a fixed-bed reactor. The main products were propylene, ethylene and COx. The prepared catalysts over TiO2 and γ-Al2O3 were evaluated under reactor test conditions of 500 °C, feed of C3H8/air with molar ratio of 0.6, and total feed flow rate of 90 mL min–1. These resulted in optimum values of 35.53 and 23.88 % for the propylene selectivity and propane conversion, respectively 6 h after the start of the reaction. The comparison of performances made between the synthesized materials and those available in the open literature for the ODHP reaction was indeed satisfactory.
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- 2016
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26. Graphene based catalysts for deep hydrodesulfurization of naphtha and diesel fuels: A physiochemical study
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Alimorad Rashidi, Mansour Bazmi, Mohammad Kazemeini, and Zeinab Hajjar
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Materials science ,Thermal desorption spectroscopy ,Graphene ,General Chemical Engineering ,Organic Chemistry ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Fuel Technology ,chemistry ,law ,Temperature-programmed reduction ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Cobalt ,Hydrodesulfurization ,Space velocity - Abstract
In this study, graphene materials have been synthesized with solid camphor (C 10 H 16 O) and methane gas as carbon precursors using atmospheric pressure chemical vapor deposition (CVD) technique at a temperature range of 900–1000 °C for a period of 45 min over copper nanoparticles. Influence of the carbon precursors upon the shape, number of layers and yield of the synthesized graphene samples has been investigated. In this venue, the compounds synthesized were functionalized with oxygen groups and impregnated by cobalt and molybdenum active phases. Moreover, the total metal loading and Co/Mo weight ratio of prepared compounds were adjusted to their industrial nominal values of 10% and 0.33, respectively. The synthesized compounds were characterized through the Transmission Electron Microscopy (TEM), Raman Spectroscopy and X-ray Diffraction (XRD) techniques as well as; BET–BJH, Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Inductively Coupled Plasma (ICP), Temperature Programmed Reduction (TPR), and Temperature Programmed Desorption of ammonia (NH 3 -TPD) analyses. In terms of synthesis of graphene material, results revealed that graphene sheets with a high yield of 90% and less than 5 layers were obtained from camphor. Ultimately, the evaluations of the HDS of naphtha with 1350 ppm of sulfur demonstrated a considerably higher activity of the carbonaceous based catalysts synthesized (98.5–100% S-removal) compared with the industrialalumina based catalyst (92.6% S-removal). Moreover, as a significant result, the sulfur content of the diesel feed was reduced from 13,000 to 15 ppm using camphoric based catalysts at approximately mild reaction conditions (300 °C, 15 bar hydrogen pressure, 100 NL/L H 2 /feed ratios, and LHSV of 5 h −1 ).
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- 2016
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27. Transesterification of sunflower oil to biodiesel fuel utilizing a novel K2CO3/Talc catalyst: Process optimizations and kinetics investigations
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Samahe Sadjadi, Mohammad Kazemeini, and Milad Zehtab Salmasi
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0106 biological sciences ,Biodiesel ,food.ingredient ,010405 organic chemistry ,Sunflower oil ,Transesterification ,Heterogeneous catalysis ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,food ,Reaction rate constant ,chemistry ,Chemical engineering ,Biodiesel production ,Methanol ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
A novel efficient and cost-effective heterogeneous catalyst for the production of biodiesel from transesterification of sunflower oil was prepared through the impregnation of K2CO3 upon the Talc material. The physicochemical features of the catalyst were studied through several characterization analyses. The effect of the K2CO3 loading was investigated by comparing the catalytic activity of various prepared catalysts. Moreover, the effect of the calcination temperature upon the catalytic activity was examined. To maximize the yield of the produced biodiesel fuel, reaction variables such as the reaction time and temperature, catalyst concentration, and methanol: oil molar ratio were optimized. Additionally, the kinetics of the reaction was understudied. Results revealed that the catalyst with 40 wt.% of K2CO3 calcined at 823 K possessed the highest catalytic activity. That is the biodiesel production yield of 98.4 %. Moreover, the kinetic parameters of the reaction rate constant of 0.01558 min−1, Eact of 62.4 kJ/mol, and Eyring-Polanyi’s ΔH and ΔS of 59.7 kJ/mol and -103.7 J/(mol K), respectively were obtained for this material. These were revealed under the optimum reaction condition of the catalyst reactor loading of 4 wt.% as well as the methanol: oil molar ratio of 6:1 operated at 338 K. Furthermore, the optimized catalyst was demonstrated to successfully withstand the aforementioned optimum criteria up to five consecutive reaction cycles while experiencing a negligible loss of about 8% of its activity.
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- 2020
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28. The oxidative desulfurization process performed upon a model fuel utilizing modified molybdenum based nanocatalysts: Experimental and density functional theory investigations under optimally prepared and operated conditions
- Author
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Alimorad Rashidi, Abdolvahab Seif, Saeed Hasannia, and Mohammad Kazemeini
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Materials science ,Oxide ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Nanomaterial-based catalyst ,0104 chemical sciences ,Surfaces, Coatings and Films ,Flue-gas desulfurization ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,X-ray photoelectron spectroscopy ,Dibenzothiophene ,Molybdenum ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
CoMo/reduced graphene oxide (rGO) catalyst was synthesized for the oxidative desulfurization process (ODS) of dibenzothiophene (DBT) in n-decane. Parameters including total metal (Co and Mo) loading, Co/Mo and CA (citric Acid)/Mo molar ratios were investigated toward achieving optimum conditions. The catalysts were characterized by the XRD, ICP, FTIR, Raman Spectroscopy, BET-BJH, NH3-TPD, XPS, and TEM methods. The product sulfur content was measured by the ICP-OES while the product was evaluated using FTIR and 1H NMR analyses. All experimental stages were designed using Design-Expert software. High BET area, acidity, uniform particle size, and Co-promoter played key roles in this performance. Results revealed 99% for the DBT conversion in 1 h using CoMo (20)/rGO catalyst. The density functional theory (DFT) showed enhancement of interaction energy of the DBT by about 1215 kJ/mol. This emphasized the observed faster ODS reaction. Besides, it was demonstrated that the charge was transferred mainly from rGO to CoMo amplifying both production of interfacial built-in electric field and electrostatic interaction of DBT with the catalyst surface.
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- 2020
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29. A study of the DR23 dye photocatalytic degradation utilizing a magnetic hybrid nanocomposite of MIL-53(Fe)/CoFe2O4: Facile synthesis and kinetic investigations
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Niyaz Mohammad Mahmoodi, Mohammad Kazemeini, and Seyed Behnam Bagherzadeh
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Materials science ,Nanocomposite ,Composite number ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Catalysis ,Chemical engineering ,Materials Chemistry ,Photocatalysis ,Magnetic nanoparticles ,Physical and Theoretical Chemistry ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Photodegradation ,Spectroscopy - Abstract
In this research, cobalt ferrite (CoFe2O4) magnetic nanoparticles as well as MIL-53(Fe) structure were synthesized by the hydrothermal and solvothermal methods, respectively. Moreover, magnetic composites of MIL-53(Fe)/CoFe2O4 nanoparticles with different cobalt ferrite loadings (i.e.; 0.05, 0.1 and 0.2 g) were prepared via the solvothermal method. The main novelty of the present research was to synthesize a magnetic composite of MIL-53(Fe)/CoFe2O4 nanoparticles in order to perform rapid photodegradation of Direct Red 23 (DR23) dye under the LED visible light irradiation. Good magnetic properties of the fabricated composite led to easy separation and rapid retrieval of the catalyst from the reaction mixture. Effects of operational variables such as the initial dye concentration, photocatalyst loading and solution pH upon the performance of synthesized materials were understudied. Characterizations of the prepared photocatalysts were performed through the XRD, SEM, TEM, EDX, FTIR, as well as VSM, DRS, BET-BJH and EIS analyses. Results of the XRD, SEM and FTIR analyses confirmed successful synthesis of CoFe2O4, MIL-53(Fe) and their magnetic composites. Moreover, the desired magnetic value of 28.5 emu/g at 8128 Oe was determined for the MIL-53(Fe)/0.1gCoFe2O4 material. Furthermore, the highest light absorption intensity by this composite was obtained through the UV–Visible DRS analysis. In addition, the value of optical bandgap energy (Eg) for the aforementioned composite was determined to be 2.1 eV. Furthermore, the BET surface areas of the MIL-53(Fe), MIL-53(Fe)/0.1gCoFe2O4 and CoFe2O4 species were evaluated to be 13, 34 and 52 m2/g, respectively. Finally, the photocatalytic degradation of the DR23 over the MIL-53(Fe)/0.1gCoFe2O4 was revealed to be 99.35% after 80 min of duration under the LED irradiations. This was higher than the rest of other understudied materials. In addition, results displayed that, the hydroxyl radicals ( OH) as well as photo-generated holes (h+) were the main active species in photocatalytic degradation process undertaken. Ultimately, sufficient yet simple rate law models of the aforementioned dye degradation implementing first- and second-order chemical kinetics upon the prepared catalysts were developed.
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- 2020
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30. Simulation of Propane Dehydrogenation to Propylene in a Radial-Flow Reactor over Pt-Sn/Al2O3as the Catalyst
- Author
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Seyed Mohammadreza Miraboutalebi, Leila Vafajoo, Moslem Fattahi, and Mohammad Kazemeini
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Exothermic reaction ,Argon ,Materials science ,General Chemical Engineering ,chemistry.chemical_element ,General Chemistry ,Photochemistry ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,Petrochemical ,chemistry ,Chemical engineering ,Propane ,Dehydrogenation ,Inert gas ,Selectivity - Abstract
Catalytic paraffin dehydrogenation for manufacturing olefins is considered to be one of the most significant production routes in the petrochemical industries. A reactor kinetic model for the dehydrogenation of propane to propylene in a radial-flow reactor over Pt-Sn/Al2O3 as the catalyst was investigated here. The model showed that the catalyst activity was highly time dependent. In addition, the component concentrations and the temperature varied along the reactor radius owing to the occurring endothermic reaction. Moreover, a similar trend was noticed for the propane conversion as for the propylene selectivity, with both of them decreasing over the time period studied. Furthermore, a reversal of this trend was also revealed when the feed temperature was enhanced or when argon was added into the feed as an inert gas.
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- 2015
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31. Amine-functionalized magnetic nanocomposite particles for efficient immobilization of lipase: effects of functional molecule size on properties of the immobilized lipase
- Author
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Mohammad Kazemeini, Parvaneh Esmaeilnejad-Ahranjani, Ayyoob Arpanaei, and Gurvinder Singh
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Nanocomposite ,Immobilized enzyme ,biology ,Chemistry ,General Chemical Engineering ,General Chemistry ,Catalysis ,Chemical engineering ,Covalent bond ,Zeta potential ,biology.protein ,Organic chemistry ,Surface modification ,Magnetic nanoparticles ,Lipase - Abstract
A cost-effective design of reusable enzyme-functionalized particles with better catalytic activity is of great scientific interest due to their applications in a wide range of catalytic reactions in several industrial processes. In this work, a systematic approach for preparing amine-functionalized magnetic nanocomposite particles through the surface modification of core/shell type Fe3O4 cluster@SiO2 particles by the small molecules of 3-(2-aminoethyl)aminopropyltrimethoxysilane (AAS) or the large molecules of polyethyleneimine (PEI) with two different molecular weights, as the support materials for enzyme immobilization, has been demonstrated. The functional nanocomposite particles were characterized by STEM, XRD, EDX, VSM, TGA, FTIR, oxygen elemental analysis and zeta potential measurement techniques. Lipase from Pseudomonas cepacia, chosen as a model enzyme, was covalently immobilized on glutaraldehyde-activated particles. The free and immobilized lipases were characterized by UV-vis, FTIR and CD spectroscopic methods. It has been shown that the size of the functional molecule has a significant effect on the concentration of binding sites on the particles and consequently on the lipase immobilization efficiency and loading capacity as well as the conformation and activity of the immobilized lipase. Resulting from the increased binding site concentration on the low and high molecular weight PEI-functionalized particles' surface, high lipase immobilization efficiencies (87 and 97%, respectively) and loading capacities (803 and 817 mg g−1, respectively) were obtained. Upon the immobilization of lipase, the activity, thermal and storage stability as well as reusability were improved under harsh reaction conditions in the order of the lipase immobilized on the low molecular weight PEI > high molecular weight PEI > AAS functionalized particles. This study offers insight into the design of functionalized magnetic particles for efficient immobilization of enzymes as well as improvement of the immobilized enzymes properties. This journal is © The Royal Society of Chemistry 2015
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- 2015
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32. Morphological investigations of nanostructured V2O5 over graphene used for the ODHP reaction: from synthesis to physiochemical evaluations
- Author
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Alimorad Rashidi, Mohammad Kazemeini, Farhad Khorasheh, and Moslem Fattahi
- Subjects
Materials science ,Graphene ,Inorganic chemistry ,Side reaction ,Vanadium ,chemistry.chemical_element ,Catalysis ,Nanomaterial-based catalyst ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Propane ,Dehydrogenation ,Nanorod - Abstract
Oxidative dehydrogenation of propane (ODHP) in a fixed-bed reactor over synthesized vanadia nanocatalysts was investigated physicochemically. Several vanadium pentoxide (V2O5) nanostructures including rod-, belt-, tube-, needle- and flower-like forms were successfully synthesized via reflux and hydrothermal processes utilizing different templates such as monoamines, diamines, aromatic and alcoholic amines. The morphologies of the obtained products were found to be sensitive to the types of templates used. Nanorods obtained were 1.4 μm in length and about 97 nm in width while the VO2(B) nanotubes were of about 76 nm average diameter and up to 1.2 μm long. The diameters of the V2O5 nanotubes varied between 60 and 120 nm with lengths up to 5 μm. In this way, the as-synthesized vanadium nanostructures with amines doped on graphene with a 1 : 1 molar ratio of V : C were prepared both through reflux and hydrothermal methods. The surface morphologies were determined by scanning electron microscopy (SEM). The structure of the prepared samples was then characterized utilizing the XRD, BET/BJH, FTIR, UV-vis and TGA techniques. Amongst the materials investigated, the bulk catalyst of V2O5 prepared with dodecylamine and V2O5 synthesized by aniline on graphene was shown to be the most active catalyst for the ODHP reaction. The reactor test conditions of 450 °C, feed of C3H8/air molar ratio of 0.5 and total feed flow rate of 60 mL min−1 over vanadium on graphene resulted in 53.93% selectivity for propylene at 47.02% propane conversion after 6 h, at the end of the reaction. It was revealed that under these conditions the cracking of propane or propylene along with COx formation as a side reaction occurred. Moreover, the effects of different reaction temperatures as well as the propane-to-air ratio on propane conversion and product selectivities on the two optimized catalysts designated as V-DDA and V-A-G were investigated.
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- 2015
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33. Fabrication of MEA based on sulfonic acid functionalized carbon supported platinum nanoparticles for oxygen reduction reaction in PEMFCs
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Ahmad Heydari, Fatemeh Yasi, Farhad Golmohammadi, Hussein Gharibi, and Mohammad Kazemeini
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chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Sulfuric acid ,General Chemistry ,Sulfonic acid ,Electrocatalyst ,Platinum nanoparticles ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Nafion ,Platinum ,Ionomer - Abstract
The Nafion ionomer affects the efficiency of the platinum (Pt) catalyst by blocking the active sites thereby restricting the gas permeability of the catalyst layer; but, there is a limitation in the quantity of Nafion ionomer that needs to be added without affecting the cell performance. Sulfonation of carbon-supported catalysts as mixed electronic and protonic conductors has been reported to be an efficient way to increase the triple-phase boundaries. In order to improve the utilization and activity of cathodic catalysts in the oxygen reduction reaction (ORR), Pt nanoparticles were loaded on a mixture of Vulcan XC-72R and MWCNTs, which were functionalized in a mixture of 96% sulfuric acid and 4-aminobenzenesulfonic acid using sodium nitrite to produce intermediate diazonium salts from substituted anilines. The influence of sulfonation on the structural, surface, morphological and catalytic characteristics of the catalysts was explored using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and electrochemical techniques. The performance of the ORR was optimal under the following conditions: 75 wt% f-MWCNTs and 25 wt% f-Vulcan XC-72R (5%). The optimum loading of Nafion was found to be 15 wt% and the MEA was fabricated according to this Nafion loading which is lower than that of other MEAs. The maximum power density of MEA with the modified electrocatalyst was 1.6 times more than that of MEA with the unmodified electrocatalyst.
- Published
- 2015
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34. Transesterification of Canola Oil to Biodiesel Using CaO/Talc Nanopowder as a Mixed Oxide Catalyst
- Author
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Hesam Maleki, Farzad Bastan, and Mohammad Kazemeini
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inorganic chemicals ,General Chemical Engineering ,02 engineering and technology ,010402 general chemistry ,Talc ,01 natural sciences ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,medicine ,Organic chemistry ,heterocyclic compounds ,Biodiesel ,Chemistry ,organic chemicals ,General Chemistry ,Transesterification ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemical engineering ,Biodiesel production ,Mixed oxide ,Leaching (metallurgy) ,Methanol ,0210 nano-technology ,medicine.drug - Abstract
A series of heterogeneous catalysts including different molar ratios of CaO/talc was synthesized to study the transesterification reaction of canola oil and methanol under different reaction conditions. Characterization and kinetic results revealed that the activity of this catalyst was enhanced due to the increase of CaO/talc molar ratio value leading to an improvement in the biodiesel production. Moreover, the effect of various parameters on the activity of the undertaken catalysts was studied in order to determine the optimum process conditions. Ultimately, leaching measurements and the durability of the CaO/talc catalyst under several reaction cycles were investigated exhibiting it to be a stable catalyst.
- Published
- 2017
35. An investigation of the oxidative dehydrogenation of propane kinetics over a vanadium–graphene catalyst aiming at minimizing of the COx species
- Author
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Alimorad Rashidi, Farhad Khorasheh, Mohammad Kazemeini, and Moslem Fattahi
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Chemistry ,General Chemical Engineering ,Kinetics ,Thermodynamics ,General Chemistry ,Industrial and Manufacturing Engineering ,Volumetric flow rate ,Catalysis ,Chemical kinetics ,chemistry.chemical_compound ,Propane ,Environmental Chemistry ,Dehydrogenation ,Response surface methodology ,Nonlinear regression ,Simulation - Abstract
In the current investigation, an application of the design of experiments (DOE) along with the artificial neural networks (ANN) in a kinetic study of oxidative dehydrogenation of propane (ODHP) reaction over a synthesized vanadium–graphene catalyst at 400–500 °C presented aiming at minimizing the CO x production. In this venue, the main and side reactions’ unknown and variable reaction kinetics network expressed through the power law equations and determined via non-linear regression analysis. The collected kinetic experimental data attributed to three operating factors including the temperature, feed molar ratio and total feed flowrate. The neural network-based optimum was compared with that of the experimental data. In addition, the predictions of the response surface methodology (RSM) and ANN models based upon the DOE information utilized to generate extra simulated data for further analysis. Then different data sets used to fit the power law kinetic rates for the main ODHP and side reactions. Propane to air ratio was found to be a critical parameter for optimization of the ODHP reaction. Distribution of the propane consumption rate as well as the propylene and ethylene formation rates to that of the CO x investigated and optimizations were performed. It was revealed that, based on different number of data points utilized over the vanadium–graphene catalyst these ratios were higher than unity confirming that, the CO x production minimized. Moreover, under such conditions, the ratio of ethylene to CO x production rate was noticeably below unity indicating the CO x formation was higher than that of the ethylene. Kinetic modeling results incorporating simulated data from the ANN and RSM models compared with those obtained from the experimental ones resulted in less than 10% deviations. Considering the complexity of the undertaken system, this comparison was rather satisfactory.
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- 2014
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36. Development of a structured monolithic support with a CNT washcoat for the naphtha HDS process
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Kh. Jafari Jozani, Alimorad Rashidi, E. Soghrati, and Mohammad Kazemeini
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geography ,Materials science ,geography.geographical_feature_category ,General Chemical Engineering ,General Chemistry ,Carbon nanotube ,engineering.material ,law.invention ,Catalysis ,Coating ,Chemical engineering ,law ,engineering ,Monolith ,Mesoporous material ,Naphtha ,Layer (electronics) ,BET theory - Abstract
An acid treatment of the cordierite monolith followed by coating of the CNT onto it by means of catalytic decomposition of methane was performed. The resulting material utilized as the support for the CoMo catalyst. The characterization outcomes showed that the CNTs were distributed uniformly on the surface of the monolith leading to a high BET surface area and relatively good adhered mesoporous layer of CNTs. Moreover, the catalytic activity of the resulting catalysts determined in an HDS reaction of naphtha. It was concluded that the activity of the CoMo catalyst over the CNT coated monolithic support (FACNT) was higher than that of the CoMo deposited onto the acid-treated monolith and CoMo/γ-Al2O3 conventional catalyst. Ultimately, the HDS reaction over the CoMo/FACNT material under optimized operating conditions reduced the sulfur content of naphtha from 2670 to 13 ppm.
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- 2014
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37. A Physicochemical Evaluation of Modified HZSM-5 Catalyst Utilized for Production of Dimethyl Ether From Methanol
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Mohammad Kazemeini, Mona Zamani Pedram, A. Amjadian, and Moslem Fattahi
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Kerosene ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,Energy Engineering and Power Technology ,General Chemistry ,Coke ,Activation energy ,Geotechnical Engineering and Engineering Geology ,medicine.disease ,Catalysis ,law.invention ,chemistry.chemical_compound ,Fuel Technology ,Magazine ,law ,medicine ,Dimethyl ether ,Dehydration ,Methanol - Abstract
A number of HZSM-5 catalysts modified with 5 wt% Mg, Na, Zr, and Al as well as others modified with 5–60 wt% Zn prepared by wet impregnation. These materials were characterized by the NH3-TPD, XRF, and XRD analyses and tested in a slurry reactor to determine their activities in dehydration of methanol solution in kerosene. Reactions were carried out at 230°C and 19 bar for 4 h of residence time in the reactor. Results showed that in the first series, the catalyst modified with Zr and in the second series, the one modified with 10 wt% Zn led to the highest methanol conversion. It was deduced that elimination of strong acid sites and partial replacement of active cations in the HZSM-5 zeolite lattice enhanced the performance and improved resistance against formation of hydrocarbons and other by-products such as olefins all of which acted as coke precursors. In order to determine the activation energy, the rate equation of Bercic and Levec was utilized and assumptions consistent with reaction conditions cons...
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- 2014
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38. DME DIRECT SYNTHESIS FROM SYNGAS IN A LARGE-SCALE THREE-PHASE SLURRY BUBBLE COLUMN REACTOR: TRANSIENT MODELING
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Sadegh Papari, Moslem Fattahi, Mehrab Fatahi, and Mohammad Kazemeini
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Waste management ,General Chemical Engineering ,Nuclear engineering ,General Chemistry ,Catalysis ,Coolant ,chemistry.chemical_compound ,chemistry ,Three-phase ,Slurry ,Dimethyl ether ,Transient (oscillation) ,Syngas ,Bubble column reactor - Abstract
In this research, a new transient mathematical model based upon tanks-in-series configuration was developed to simulate the direct synthesis of dimethyl ether (DME) from syngas in a commercial-scale slurry bubble column reactor. A comparison between the simulation results and experimental data showed that the applied model might acceptably describe the behavior of the slurry reactor. Furthermore, simulation results in the heterogeneous bubble flow regime indicated that the proposed model with 10 tanks-in-series provided the optimum condition. Utilizing this transient model and considering catalyst deactivation, the effect of operating conditions on DME productivity and CO conversion were investigated. In addition, the dynamic behavior of the reactor was studied after implementing a step change in the reactor's coolant fluid temperature.
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- 2014
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39. Vanadium Pentoxide Catalyst over Carbon-Based Nanomaterials for the Oxidative Dehydrogenation of Propane
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Moslem Fattahi, Alimorad Rashidi, Farhad Khorasheh, and Mohammad Kazemeini
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Materials science ,Graphene ,General Chemical Engineering ,Inorganic chemistry ,Vanadium ,chemistry.chemical_element ,General Chemistry ,Carbon nanotube ,Industrial and Manufacturing Engineering ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Propane ,law ,Pentoxide ,Dehydrogenation ,BET theory - Abstract
A series of V2O5 catalysts supported on multiwall carbon nanotube (MWCNT), single wall carbon nanotube (SWCNT), and graphene were synthesized by hydrothermal and reflux methods for oxidative dehydrogenation of propane (ODHP) to propylene. The catalysts were characterized by techniques including the BET surface area measurements, XRD, FTIR, H2-TPR, NH3-TPD, FESEM, and UV–vis diffuse reflectance spectroscopy. The performance of the catalysts and the supports were subsequently examined in a fixed bed reactor. The main products were propylene, ethylene and COx. The vanadium catalyst supported on graphene with C/V molar ratio of 1:1 synthesized through the hydrothermal method had the best performance under the reactor test conditions of 450 °C, feed C3H8/air molar ratio of 0.6, and the total feed flow rate of 90 mL/min resulting in average values of 53.6% and 50.7% for propylene selectivity and propane conversion, respectively. This catalyst was further employed in a series of experiments to study the effects ...
- Published
- 2013
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40. Evaluation of biodiesel production using lipase immobilized on magnetic silica nanocomposite particles of various structures
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Mohammad Kazemeini, Mohammad Kalantari, and Ayyoob Arpanaei
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Biodiesel ,Environmental Engineering ,biology ,Immobilized enzyme ,Biomedical Engineering ,Bioengineering ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Biodiesel production ,biology.protein ,Organic chemistry ,Glutaraldehyde ,Methanol ,Lipase ,Mesoporous material ,Biotechnology - Abstract
Nonporous and mesoporous silica-coated magnetite cluster nanocomposites particles were fabricated with various silica structures in order to develop a desired carrier for the lipase immobilization and subsequent biodiesel production. Lipase from Pseudomonas cepacia was covalently bound to the amino-functionalized particles using glutaraldehyde as a coupling agent. The hybrid systems that were obtained exhibited high stability and easy recovery regardless of the silica structure, following the application of an external magnetic field. The immobilized lipases were then used as the recoverable biocatalyst in a transesterification reaction to convert the soybean oil to biodiesel with methanol. Enzyme immobilization led to higher stabilities and conversion values as compared to what was obtained by the free enzyme. Furthermore, the silica structure had a significant effect on stability and catalytic performance of immobilized enzymes. In examining the reusability of the biocatalysts, the immobilized lipases still retained approximately 55% of their initial conversion capability following 5 times of reuse.
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- 2013
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41. Effects of functionalization and catalyst treatments on selective behavior of multi-walled carbon nanotube-supported palladium catalysts in hydrogenation of acetylene
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Alimorad Rashidi, Mohammad Kazemeini, and H. Bazzazzadegan
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Materials science ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Carbon nanotube ,Nanomaterial-based catalyst ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Acetylene ,law ,Surface modification ,Particle size ,Selectivity ,Palladium - Abstract
Two nanocatalysts of palladium over multi-walled carbon nanotubes (MWCNT) were synthesized and their catalytic properties evaluated in selective hydrogenation of acetylene. Different procedures were applied to synthesize catalysts which resulted in two distinct average particle sizes of palladium (Pd) over the MWCNT. The resulting catalysts displayed dissimilar NH3-TPD behaviors as well as different selectivity performances at lower temperatures. While enhancement of the hydrogen transfer mechanism occurred upon the temperature increase, similar behaviors for the aforementioned materials were obtained. Furthermore, it was revealed that the catalytic performance at higher temperatures did not depend upon the Pd particle size or heterogeneous energetic sites formed during functionalizing of the MWCNT material.
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- 2013
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42. Investigation of carbon monoxide tolerance of platinum nanoparticles in the presence of optimum ratio of doped polyaniline with para toluene sulfonic acid and their utilization in a real passive direct methanol fuel cell
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Hassan Pahlavanzadeh, Hussein Gharibi, Mohammad Kazemeini, and Mitra Amani
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chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,Sulfonic acid ,Electrocatalyst ,Platinum nanoparticles ,Catalysis ,chemistry.chemical_compound ,Direct methanol fuel cell ,chemistry ,Chemical engineering ,Polyaniline ,Electrochemistry ,Methanol ,Methanol fuel - Abstract
Polyaniline fiber (PANI) was synthesized by chemical interfacial method and doped with para toluene sulfonic acid (PTSA) through a sequential doping–dedoping–redoping process resulting in PANI-PTSA. The doped material was utilized to fabricate Vulcan-polyaniline composite of C-PANI-PTSA. Next, through reduction, Pt particles were deposited on to this composite to produce a Pt/C-PANI-PTSA electrocatalyst. To investigate the PANI-PTSA interaction with the carbon support as well as, to consider its effect upon the catalytic activity of Pt/C-PANI-PTSA, electrocatalysts with different ratios of 10, 15, 20, 25 and 30 wt% were synthesized and their activity was compared with the Pt/C (Electrochem). Results revealed that, the peak current density in methanol electro-oxidation, electrochemical surface area, methanol diffusion coefficient, charge transfer resistance as well as; the stability of the Pt/C-20%PANI-PTSA electrocatalyst were all markedly improved for the synthesized material. Moreover, the Pt/C-20%PANI-PTSA was demonstrated to be more CO tolerant according to the CO stripping voltammetry test. Also powder XRD and TEM techniques were utilized to investigate the crystallite size and the surface morphologies of the catalysts. Finally, the performance of Pt/C-20%PANI-PTSA was compared with Pt/C (Electrochem) in a passive direct methanol fuel cell and the effect of PANI-PTSA on methanol crossover and fuel utilization was analyzed. Ultimately, the Pt/C-20%PANI-PTSA modified catalyst was shown to be more suitable for applying in the direct methanol fuel cells (DMFC) compared with the commercial Pt/C material.
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- 2013
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43. The joint reaction of methanol and i-butane over the HZSM-5 zeolite
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Alireza Mohammadrezaee, Reza Golhosseini, Gholamreza Roohollahi, and Mohammad Kazemeini
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chemistry.chemical_compound ,Methanol reformer ,chemistry ,General Chemical Engineering ,Yield (chemistry) ,Organic chemistry ,Butane ,Methanol ,Zeolite ,Residence time (fluid dynamics) ,Product distribution ,Nuclear chemistry ,Catalysis - Abstract
The effects of i-butane addition to methanol in MTP reaction were investigated over an in-house prepared HZSM-5 catalyst. It was observed that, propylene yield would be enhanced when i-butane fed to the reactor along with methanol. The rising growth of the propylene yield continued to peak on till the balance in thermal condition established. Similar trends have been observed when water was added to the mixture. The effect of WHSV with fixed water composition on product distribution was also studied. The optimum point where the highest amount of propylene yielded was shown to be high depended upon the temperature and residence time.
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- 2013
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44. Investigating the effect of calcination repetitions on the lifetime of Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis utilising the precursor's solution affinities
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Jamshid Zarkesh, Mohammad Reza Hemmati, Farhad Khorasheh, and Mohammad Kazemeini
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Materials science ,General Chemical Engineering ,Sintering ,Mineralogy ,chemistry.chemical_element ,Fischer–Tropsch process ,General Chemistry ,Porosimetry ,law.invention ,Catalysis ,Cobalt catalyst ,Chemical engineering ,chemistry ,law ,Calcination ,Selectivity ,Cobalt - Abstract
Cobalt-based catalysts were prepared on different alumina supports, and their behaviour for different Fischer–Tropsch synthesis (FTS) conditions assessed. Although Co/γ-Al2O3 is a well-known FTS catalyst, its durability ought to be improved to make the industrial process economically feasible. Here calcination repetitions effects on the catalyst lifetime were examined utilising reactor tests and characterisation techniques including XRD, TPR, ICP and N2 porosimetry. Results revealed that fewer calcination repetitions improved catalyst activity and selectivity. Based upon the XRD results, these findings appeared to be due to the improved size of cobalt crystals on the pore surfaces. These translated into the affinity of the precursor solution towards different surfaces which were ranked in this research. Catalyst characterisations demonstrated that fewer calcination repetitions yielded a larger surface area and pore volume due to less sintering. TPR analysis indicated that fewer calcination repetitions resulted in improved reduction, hence more available surface cobalt for reaction.
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- 2013
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45. Artificial intelligence techniques for modeling and optimization of the HDS process over a new graphene based catalyst
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Shokoufe Tayyebi, Alimorad Rashidi, Mohammad Kazemeini, and Zeinab Hajjar
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010405 organic chemistry ,Graphene ,Organic Chemistry ,Oxide ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Sulfur ,0104 chemical sciences ,law.invention ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,law ,Scientific method ,0210 nano-technology ,Hydrodesulfurization ,Naphtha - Abstract
A Co-Mo/graphene oxide (GO) catalyst has been synthesized for the first time for application in a defined hydrodesulfurization (HDS) process to produce sulfur free naphtha. An intelligent model based upon the neural network technique has then been developed to estimate the total sulfur output of this process. Process operating variables include temperature, pressure, LHSV and H2/feed volume ratio. The three-layer, feed-forward neural network developed consists of five neurons in a hidden layer, trained with Levenberg–Marquardt, back-propagation gradient algorithm. The predicted amount of residual total sulfur is in very good agreement with the corresponding experimental values revealing a correlation coefficient of greater than 0.99. In addition, a genetic algorithm (GA) has been employed to optimize values of total sulfur as well as reaction conditions.
- Published
- 2016
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46. Reaction kinetics determination and neural networks modeling of methanol dehydration over nano γ-Al2O3 catalyst
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S. Alamolhoda, AmirAli Zaherian, Mohammad Kazemeini, and M.R. Zakerinasab
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Reaction rate ,Chemical kinetics ,chemistry.chemical_compound ,Reaction rate constant ,Dehydration reaction ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,Dimethyl ether ,Rate equation ,Methanol ,Catalysis - Abstract
In this research nano γ-Al 2 O 3 catalyst was synthesized through precipitation process then characterized and utilized for methanol dehydration reaction in a slurry batch reactor in route to the indirect synthesis of the dimethyl ether (DME). In this venue, effects of the key parameters on methanol conversion and catalyst stability were investigated. Moreover, the internal and external mass transfer resistances were eliminated; hence the intrinsic kinetics controlled the reaction. Therefore, the optimum conditions for temperature, methanol concentration, catalyst mass and stirrer speed were determined to be 300 °C, 1.18 mol/l, 1.5 g and 1100 rpm, respectively. Next, different reaction rate equations from literature were applied to the measured experimental data where their generality compared to a new reaction rate equation examined. Ultimately, artificial neural networks applied to determine a model for the reaction rate estimation. It has been shown that the proposed reaction rate equation might be used rather satisfactorily to provide a base model for the neural networks; consequently a very good proximity to the reaction dynamics resulted.
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- 2012
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47. Effect of lanthanum doping on the lifetime of Co/γ-Al2O3 catalysts in Fischer-Tropsch synthesis
- Author
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Mohammad Reza Hemmati, Farhad Khorasheh, Mohammad Kazemeini, and Jamshid Zarkesh
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Materials science ,General Chemical Engineering ,Inorganic chemistry ,Doping ,chemistry.chemical_element ,Fischer–Tropsch process ,General Chemistry ,Porosimetry ,Catalysis ,chemistry ,Aluminium ,Lanthanum ,Selectivity ,Cobalt - Abstract
Cobalt-based catalysts were prepared on gamma alumina supports, and their behaviour for different Fischer-Tropsch synthesis (FTS) conditions was assessed. Although Co/γ-Al2O3 is a well-known FTS catalyst, its durability ought to be improved to make the industrial process economically feasible. The effect of lanthanum doping on the catalyst lifetime was examined utilising reactor tests and catalyst characterization techniques including TPR, ICP and N2 porosimetry. Reactor test results revealed that an optimum amount of lanthanum improved catalyst activity and selectivity. Increasing amounts of lanthanum doping up to about 1.1 wt% seemed to modify the chemical composition of the support resulting in improved catalyst selectivity and lifetime. Further increase in lanthanum doping up to 2.7 wt% only marginally enhanced the catalyst selectivity and lifetime. TPR results revealed that the high temperature peak due to cobalt aluminate phase shifted to lower temperatures with increasing amount of doped lanthanum possibly due to the formation of lanthanum/aluminium mixed oxides.
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- 2012
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48. Platinum Extraction from Spent Catalysts by TOPO Utilizing RSM Technique
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Hesam Hassan Nejad, Moslem Fattahi, and Mohammad Kazemeini
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Design–Expert ,Chromatography ,Materials science ,Extraction (chemistry) ,Inorganic chemistry ,General Engineering ,chemistry.chemical_element ,Separation process ,Catalysis ,chemistry.chemical_compound ,chemistry ,Salting out ,Response surface methodology ,Platinum ,Trioctylphosphine oxide - Abstract
In this research, data on liquid-liquid extraction of platinum from commercial spent catalysts by trioctylphosphine oxide (TOPO) in toluene were experimentally obtained. Alkaline metal salts were used to optimize the separation process. Best Salting-out effect was obtained by KCl which extracted up to 90% of platinum utilizing TOPO. Furthermore, extraction percentages of Pt and Al depending upon different factors were investigated. It was observed that the extraction process was kinetically fast and achieving the equilibrium time took less than 30 seconds. Optimized points obtained utilizing response surface methodology (RSM) by the “Design Expert” software in order to minimize the separation factor of platinum to aluminum.
- Published
- 2012
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49. Theoretical Investigations of Methane Conversion to Heavier Hydrocarbons in a Plasma Reactor
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Shadi Roshdi Ferdosi, Moslem Fattahi, Masoud Habibi Zare, Mohammad Kazemeini, and Nora Safabakhsh
- Subjects
chemistry.chemical_compound ,Ethylene ,Acetylene ,Chemical engineering ,Chemistry ,Propane ,Yield (chemistry) ,General Engineering ,Oxidative coupling of methane ,Photochemistry ,Isothermal process ,Methane ,Catalysis - Abstract
In this study, mathematical modelling of oxidative coupling of methane (OCM) to C2hydrocarbons (C2H6and C2H4) over La2O3/CaO catalyst in a fixed-bed reactor operated under isothermal and non-isothermal conditions was investigated using the MATLAB program. In this process, methane and acetylene were the inputted feed and ethane, ethylene, propylene, propane, i-butane and n-butane were the output products. The amount of methane conversion obtained was 12.7% for the former feed however; if pure methane was inputted this conversion rose to 13.8%. Furthermore, the plasma process would enhance the conversion, selectivity towards desired product and process yield. A comparison between the thermal and the plasma process showed that the methane conversion and production yield in the plasma were higher than in the thermal process under the same operating conditions. Finally, the results of the catalytic OCM and methane conversion processes in the plasma phase were compared with one another.
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- 2012
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50. Synthesis of highly porous nanocrystalline alumina as a robust catalyst for dehydration of methanol to dimethyl ether
- Author
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Mahmoud Aghaziarati, AmirAli Zaherian, Mohammad Kazemeini, and Sarah Alamolhoda
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Materials science ,Precipitation (chemistry) ,Scanning electron microscope ,Mechanical Engineering ,Inorganic chemistry ,Porosimetry ,Nanocrystalline material ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Mechanics of Materials ,General Materials Science ,Dimethyl ether ,Methanol ,Crystallite - Abstract
Highly porous nanocrystalline alumina was synthesized using two different precipitation processes and precipitating agents, which were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosimetry analyses. Different precipitating agents yielded nanocrystalline alumina catalysts with different morphologies and textural properties. Batch precipitation using sodium bicarbonate at constant pH resulted in a highly porous nanocrystalline γ-alumina catalyst, having surface area of 351.47 m2 g−1, total pore volume of 1.68 cm3 g−1 and mean pore diameter of 19.17 nm. The mean crystallite size was also determined to be 3.8 nm, based on the XRD results. Catalytic performance of the synthesized catalysts was investigated in a slurry reactor for dehydration of methanol to dimethyl ether (DME). Commercial alumina was also investigated in order to compare results with those of synthesized materials. The aforementioned γ-alumina synthesized catalyst exhibited a much better catalytic performance than other synthesized catalysts in this research as well as the commercial alumina. Ultimately, repetition of experiments emphasized the reasonable stability of this catalyst.
- Published
- 2012
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Catalog
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