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Two-step thermochemical H2S splitting process is a promising method to recover both H2 and S from a toxic waste H2S gas via low/high metal sulfide conversion. Several studies have examined the pote...

The influence of firing temperature on characteristics and bacterial filtration of the porous ceramic membrane prepared from rice husk (20 wt%) and kaolin has been investigated. As firing temperatures increased from 900 to 1100°C, the compressive strength of membrane increased from 555.3 N/cm2 to 2992.3 N/cm2, whereas the porosity decreased from 49.4 to 30.2% due to structural condensation and mullite formation. The condensation caused pore contraction that finally improved bacterial removal efficiency from ~90% to 99%. The results suggested that the porous ceramic membrane prepared from rice husk and kaolin should be fired at ~1050°C to attain both strength and filtration efficiency.

This work investigates the effect of the ratio of the explored Pt area in the electrolyte medium and the photoanode area (REP) on the performance of dye-sensitized solar cells (DSCs). It is found that the power conversion efficiency of DSCs increases by the ascending REP. The highest power conversion efficiency, which was obtained for the cell with the REP of 64/49, was 8.40%. Furthermore, a relationship between the efficiency and fabrication cost is analyzed in terms of reducing or enhancing the surface area of CE compared to the photoanode's surface area. These findings may provide a way for the development of efficient and large-scale DSCs.

Metal oxides and their composites have been extensively studied as effective adsorbents for the removal of heavy metals from aqueous solutions in environmental remediation. In this work, Cu0.5Mg0.5Fe2O4 was synthesized by a co-precipitation method followed by calcination (900 °C) and investigated for Pb(II) adsorption. The resultant samples were characterized by various analytical techniques including X-ray diffraction, N2 adsorption–desorption, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results revealed that single-phase cubic spinel was obtained by the calcination of as-synthesized samples at a temperature of 900 °C. Cu0.5Mg0.5Fe2O4 ferrite is a mesoporous material with a surface area, a total pore volume, and an average pore size of 41.3 m2/g, 0.2 cm3/g, and 15.1 nm, respectively. Pb(II) adsorption on Cu0.5Mg0.5Fe2O4 fitted well to the Langmuir model, indicating monolayer adsorption with a maximum capacity of 57.7 mg/g. The pseudo-second-order kinetic model can exactly describe Pb(II) adsorption with the normalized standard deviation (Δq) of 1.24%. The obtained results confirmed that the Cu0.5Mg0.5Fe2O4 ternary oxides exhibit a high adsorption capacity toward Pb(II), thanks to the increase in active adsorptive sites of ferrite.

In this study, the self-assembly of 5,10,15,20-tetra(3,4,5-trimethoxyphenyl)porphyrin (coded as: TTOP) in a mixture of tetrahydrofuran (THF) and H2O and the photocatalytic activity of the resulting self-assembled aggregates toward the degradation of organic compounds were investigated. TTOP was well dispersed as monomers in THF, however, it stacked into aggregates upon the addition of water (20–90%). Depending on the THF/H2O mixture various nanostructures were observed. Microrods with an average width of 0.62 ± 0.22 μm and length of 10.17 ± 2.04 μm and sphere-like particles with diameters ranging from 0.5 to 1.2 μm were obtained in 70% water in THF. Nonetheless, the particles disappeared and the rods turned to slabs with the same length but much larger width (4.48 ± 2.27 μm) when 80% water in THF was used. Particles with irregular shapes, which connected into large aggregates, were obtained at 90% water in THF. These structures exhibited a significant difference in photocatalytic ability for the degradation of dye (rohdamine B, RhB and methylene blue, MB). The rate constants of RhB degradation were 4.35 × 10−4 min−1, 1.13 × 10−3 min−1, 2.63 × 10−3 min−1, and 3.52 × 10−3 min−1 for the porphyrin monomer in THF and its aggregate states obtained by mixing 70%, 80%, and 90% water in THF, respectively. These results indicated the important role of solvent in the formation and control of the structures of porphyrin aggregates, which are crucial to an effective porphyrin-based photocatalyst.

Dengue fever pandemic caused by dengue virus has been claimed for many lives, however, no specific treatment is available. Prevention based on vector control posed to be the most effective measure so far. The application of chitosan stabilized silver nanoparticle (AgNPs) to control larvae and adult mosquitoes has recently discovered, but their ability to inhibit Dengue virus has scarcely discussed. In this study, chitosan stabilized AgNPs have been prepared and tested against dengue virus type 1. The results showed that chitosan stabilized AgNPs can inhibit 96.66% and 98.33% dengue virus type 1 at 12.50 ppm and 25.00 ppm, respectively, without any toxicity to BHKFcɣ cells. This study confirms that chitosan stabilized AgNPs have a highly antiviral ability against dengue virus in addition to its mosquitocidal properties. This allows one to control both virus and vector simultaneously. The study suggested that chitosan stabilized AgNPs could be an effective tool to prevent the dengue epidemic.

The synthesis of advanced functional nanomaterials for electrochemical applications, such as water splitting, dye-sensitized solar cells (DSCs), and supercapacitor has been the topic of interest in recent years. This work presents the synthesis of ruthenium (Ru)/reduced graphene oxide (RGO) nanocomposite by using a facile and scalable liquid plasma-assisted method and its application as an electrode material in electrochemical applications for supercapacitor and triiodide reduction at counter electrodes (CEs) of DSCs. As the results, Ru nanoparticles have a size in the range of 4–10 nm that were homogenously distributed on the surface of the RGO layer. Electrochemical measurements demonstrated that the synthesized material is suitable for supercapacitor applications, whereas the capacitance is approximately 136.7 F·g−1 at a scan rate of 20 mV·s−1. The developed materials are applied in CEs of DSCs. We found that the efficiency of 6.78% for DSCs with CE fabricated by Ru/RGO which is higher than that of 6.20% for a cell assembled with Pt electrode.

Utilization is one of the prominent strategies for the management of hazardous industrial wastes like fly ash. As fossil-based power is expected to remain a major source of global electricity supply in the coming years, the absence of effective management strategies will exacerbate the problem of fly ash waste in the environment. Global fly ash utilization rates remain low due to limited utilization opportunities outside the construction industry. This necessitates the development of new pathways for its utilization as a means of diverting it from landfills where it poses a significant threat to the environment. Carbon capture, utilization, and storage presents opportunities to utilize fly ash in various ways; as a capture material, as a medium for permanent CO2 storage via mineralization, and as a catalyst or catalyst support for CO2 utilization processes. This study reviews the different technologies through which fly ash and materials derived from fly ash are applied in the CO2 capture, utilization, and storage technology while highlighting some challenges and opportunities for further research and development.

In gas separation and purification, adsorption using solid sorbents is very well known as an effective technology for removing acid gases. There are many applications to this technology where grafting functional groups of amines into the pore walls of silica can create a distinct adsorbent type. With this manipulation adsorbents operating conditions, regeneration, selectivity, and stability maybe controlled for a particular application such as the food industry, pharmaceuticals, textile industry, manufacturing, and shown interest in greenhouse gases mitigation. CO2 adsorption using precipitated silica supported amine is an attractive method for carbon capture technologies due to its high loading capacity, regeneration potential and low cost. H2S removal using silica has shown high loading as demonstrated by (Vaewdaow Jaiboon et al., 2014) at around 50-60wt% with an Si-TRI grafted silica [1]. Simultaneous adsorption with silica has not been extensively studied due to greater modification to the experimental setup which involves using sequential sorption and double stage bed reactors with varying feed temperatures for each species as CO2 generally takes longer to adsorb compared to H2S adding to the complexity of the dual adsorption mechanism. The purpose of this study is to synthesize precipitated silica from sodium silicate using CO2 as an acidizing agent and then impregnate polyethyleneimine (PEI) to produce CO2 adsorbent experimentally. The novel silica loading and regeneration potential will be evaluated with CO2. The adsorbent with various PEI contents from 30 to 65 wt% was prepared by a wet impregnation method. The surface area, pore volume and pore size were analysed by a nitrogen adsorption/desorption method. A scanning electron microscope was used to study the structure of the adsorbent, and a Thermogravimetric analysis (TGA) was performed using a Thermogravimetric analyser (SDT Q600). Precipitated silica having surface area of 117.9 m2/ and pore volume of 1.52 cm3/g was synthesized and used for PEI impregnation. The CO2 adsorption performance was examined using a flow Micro Reaction Calorimeter (URC) by flowing pure CO2 into analysis cell under isothermal condition. CO2 adsorption experiments will be conducted at different adsorption and regeneration temperatures to determine optimum operation temperature for CO2 capture. Preliminary results show an increase in mass of CO2 per gram of adsorbent from 89.8 to 180.04 mg/g as PEI impregnated contents increasing from 30 -60wt%, respectively. Further tests have been carried at various temperatures ranging from 60-90°C and a general increase in loading capacity was observed. When the sample was regenerated at 60°C the adsorption capacity decreased slightly for lower PEI wt% but increased higher than the first trial for higher PEI wt%. in general, with PEI 65wt% the loading of the amine dropped significantly. The outcome of this research will help strengthen the understanding of precipitated silica subjected to CO2 loading and the translation of the experimental model to a simulation model used to mimic a full-scale adsorption plant. The affinity towards CO2 will aid in the global research endeavour to study different morphologies and their optimum application space.

Offshore operations gas purification has always been limited to the marketable associated value of the gas where purification would either be onsite or sent to surface facilities for treatment. CO2 and H2S removal and gas sweetening in remote offshore locations is for the most part non-existent and CO2 is either being released into the atmosphere, within the acceptable operation limit of the platform, or being captured using conventional techniques with physical solvents such as in the selexol, rectisol, or sulfinol processes. Approximately 429.61 kg of CO2 exists in a 42-gallon barrel of distillate fuel oil and a CO2 coefficient of 0.0549 kg exists in 1 cubic foot of gas thereby emphasizing the need for an engineering solution on floating production storage and offloading (FPSO) units [1]. With strict regulation on greenhouse gases, it is increasingly paramount to utilize engineering measures to provide a contingency plan in mitigating carbon footprint with emerging novel technologies. The purpose of this study is to retrofit an existing FPSO with a CO2 capture plant; the efficiency of the capture plant, its capture capacity, and energy requirement based on experimental data will be thoroughly investigated during the scale up procedure. The research proceedings will require the use of a plethora of simulation suites which include Autodesk Fusion 360 for plant design. Further simulation will be carried out with numerical suites using Mathcad Prime 3.0 to study the scale up procedure from experimental to industrial sized adsorption unit complete with dimensions, energy requirement, capture capacity, and thermal values. The FPSO in figure 1 above presented by (Araujo et al., 2016) indicates the availability of a capture plant as part of the process train on an FPSO. Efficiency loss contribution to the system may be deduced but also it is relevant to note the custom nature of the FPSO design being independent in its operation mode compared to other profiles. The availability of the stage compressors, dehydration units, and steam generation plant as part of the FPSO operation aid in minimising the need for additional equipment for the adsorption plant, however investigation has to be made on the redirecting of processes to serve the additional components highlighted above. Primary results have shown a low tendency for dual adsorption from the initial kinetic stoichiometric balance which could also be due to the force field parameters and charges affecting the active sites. For the current concept the fixed bed experimental model from the Research and Innovation Centre on CO2 and H2 is scaled up numerically to a fixed bed height of 6.56 feet, and filled with precipitated silica impregnated with PEI solution pressurized with CO2 inflow rated at 13 lb/hr at a fixed 1.2 Bar 60°C. The operational nature of the FPSO will be modified to account for the changes requested in gas sweetening and capture programs or enhanced oil recovery. Results from the simulation will also assist in providing a tangible and relatable understanding to the complexity of solid sorption technology integration within existing processing plants. The findings of this study will help comprehend the viability of an integrated adsorption plant within an existing process train. The efficiency of the plant operation for an oil production offshore facility with associated gas or for a standalone gas field will be addressed using a feasibility study conducted for the purpose of sustainable offshore operations.

Amine-mesoporous silica has been considered as a promising CO2 adsorbent with high potential for the reduction of energy consumption and CO2 capture cost; however, its stability could greatly vary with synthetic method. In this study, adsorbents prepared by impregnating different amines including polyethylenimine (PEI) and 3-aminopropyltriethoxysilane (APTES) onto mesoporous silica were used to evaluate the effect of amines selection on the stability of adsorbents used in CO2 capture process. Results revealed that APTES impregnated mesoporous silica (APTES-MPS) is more stable than PEI-impregnated mesoporous silica (PEI-MPS); APTES-MPS was thermally decomposed at ≈280 oC, while PEI-MPS was thermally decomposed at ≈180 oC only. PEI-MPS was particularly less stable when operating under dry condition; its CO2 adsorption capacity reduced by 22.1% after 10 adsorption/regeneration cycles, however, the capacity can be significantly improved in humid condition. APTES-MPS showed a greater stability with no significant reduction in CO2 capture capacity after 10 adsorption/regeneration cycles. In general, APTES-MPS adsorbent possesses a higher stability compared to PEI-MPS thanks to the formation of chemical bonds between amino-functional groups and mesoporous silica substrate. Keywords: Mesoporous silica; CO2 capture; Adsorption; Regeneration; Emission.

One of the problems facing the desalination industry is the management of concentrated brine wastes which constitute an environmental pollution when disposed into surface water bodies. This problem is huge in regions where desalination is heavily relied upon for potable water. In this work, a process is proposed for the first time, which could make these brines safer for disposal in combination with CO2 capture and utilization for the production of chemicals like NaHCO3. Revenues from the sale of this product could offset some of the high costs which have hampered the growth of Carbon Capture, Utilization and Storage (CCUS) technology. As such, the process tackles two environmental problems while generating a valuable product. Results of the process evaluation are promising on account of the high CO2 absorption capacity of about, 1.86 mol CO2/kg carbonated solution, NaHCO3 yield of 44 g/kg carbonated solution, and a 70% and 20% overall reduction in the brine chloride and sodium concentration respectively, making it much less saline and safer to dispose into the sea.

In this study, we report the use of activated carbon synthesized from the seeds of popular local date fruits in the United Arab Emirates (UAE) as potential sorbents for carbon dioxide (CO2) adsorption applications. Activated carbons were prepared by physical methods involving furnace pyrolysis and followed by activation under CO2 atmosphere in the temperature range 600–900 °C. The evaluation of adsorption capacity of the activated carbon was supported by different characterization studies including thermogravimetric and elemental analysis, surface area and porosity measurements, infrared spectra analysis, and scanning electron microscopy. Heats of adsorption measurements were performed using a micro reaction calorimeter. Results indicate that the optimum temperature for pyrolysis of raw date seeds is 800 °C with activation period of one hour. Physically activated samples with greater pore characteristics had higher CO2 loading capacity at room temperatures, with maximum loading of 141.14 mg-CO2/g-AC for materials pyrolysed at 800 °C and activated at 900 °C. This was significantly higher than commercially obtained activated carbon samples (96.21 mg-CO2/g-AC). Overall, the date seed synthesized AC by physical method has high CO2 loading; moreover, the abundance and low cost of these date seeds may make the derived sorbent suitable for CO2 capture applications.

In this study, amine-bridged silsesquioxane (ABS) and ABS with dangling amino groups were synthesized by a facile method, without using any structure directing agents, and tested for CO2 adsorption. The covalent attachment of dangling aminopropyl groups into ABS improves CO2 adsorption significantly; CO2 loading at 30 °C increases from 83.7 to 129.6 mg g−1 by adding 3-aminopropyltriethoxysilane (APTES) to bis[3-(trimethoxysilyl)propyl]amine (BTMSPA) precursor at a molar ratio of APTES/BTMSPA = 0.5. The properties of CO2 adsorbent can be controlled by the solvent water content and aging conditions. The water content of 25 wt% produces optimal solvent conditions for a resulting adsorbent with the highest surface area (333 m2 g−1), pore volume (0.3 cm3 g−1), and CO2 loading (132 mg g−1 at 30 °C) with an aging time is 48 h in the same solvent at 60 °C. Aging in water has more effect on structural transition than ethanol; adsorbent possesses the highest pore volume (0.85 cm3 g−1) and largest pore size (15.5 nm) when it was aged in water but it has the largest surface area (447 m2 g−1) when it was aged in ethanol. Aging in ethanol results in the best sorbent with the high CO2 loading and stable CO2 adsorption activity. An adsorbent aged for 144 h in ethanol shows excellent CO2 adsorption performance in a packed bed reactor; it was relatively stable after 50 adsorption/desorption cycles with a CO2 loading capacity of 144.6 mg g−1. The success of this research offers a novel route for synthesize of ABS with minimized waste, while maintaining the quality of produced adsorbent.

In this study, a one-step preparation of amino-functionalized mesoporous silica in combination with CO 2 utilization was introduced. 3-Aminopropyltriethoxysilane (APTES) solution (30 wt% in water) was first bubbled with CO 2 at atmospheric pressure and then mixed with sodium silicate to produce amino-functionalized mesoporous silica. Resulting adsorbent was characterized and tested for CO 2 adsorption. The adsorbent has surface area and pore volume of 205.9 m 2 /g and 0.7 cm 3 /g respectively. The analysis using Fourier transform infrared spectroscopy revealed the existence of amino-functional groups on silica structure. CO 2 adsorption experiments were conducted in pure CO 2 using a flow calorimeter. The sorbent reached a maximum CO 2 loading of 35.3 mg/g at the adsorption temperature of 50 o C. The success of the proposed one-step process provides a facile method to synthesize solid adsorbent for CO 2 capture but contributes an additional option to CO 2 utilization.

Considerations for reducing global carbon emissions are influencing the development of solid sorbents such as activated carbons for carbon dioxide (CO2) capture. Adsorption efficiency often relies on method of preparation and starting or source materials. The use of agricultural wastes such as date seeds are regarded as cost- effective options to produce activated carbons for carbon capture. However, there has been no published study on the potentials of date seeds synthesized activated carbon for carbon capture. In preparing activated carbon (AC) from date seeds by physical activation technique, this study reports on the effects of pyrolysis temperature and activation time on the yield and adsorption capacities of AC produced. Optimal temperature for pyrolysis was 800 °C, while activation temperature which had the highest CO2 adsorption capacity was 900 °C with a loading of 141.14 mg adsorbed CO2/g activated carbon. Sample characteristics such as surface area and porosity, infrared spectra, and scanning electron microscopic images were also investigated in this study.

In the bid to develop cheaper adsorbents for CO2 capture applications, this work investigates the impact of polyethylenimine (PEI) impregnation on the performance of an activated fly ash material for CO2 capture. The fly ash was activated by fusing with NaOH and then subjecting to hydrothermal treatment to derive more porous zeolitic phases which were subsequently loaded with Polyethylenimine (PEI) using a wet impregnation technique. Two different PEI amines (MW∼600 and MW∼1200) were tested at varying concentrations (15%, 20%, and 25%) to study the effect of molecular weight of the PEI as well the loading percentage on the adsorption performance. The activation resulted in a significant increase in surface area from 11 m2/g in the fly ash to 270 m2/g in the activated fly ash, while the 25% PEI-600 sorbent was found to be the most efficient, giving the highest adsorption capacity of 26 mg/g adsorbent at 70 oC.

In this study, a novel and facile one-step method using CO2 for the preparation of amino-functionalized mesoporous silica for CO2 capture application was introduced. 3-Aminopropyltriethoxysilane (APTES, 30 wt % in water) was first bubbled with CO2 and then mixed with sodium silicate to produce amino-functionalized mesoporous silica. Three adsorbents, namely, precipitated silica adsorbent (PSA), silicagel adsorbent (SGA), and condense silicagel adsorbent (C-SGA), were synthesized by tuning CO2 pressure when preparing CO2 absorbed APTES solution and aging temperatures of obtained hydrogel, respectively. PSA has large primary particles (200–1000 nm) with 73.4 m2/g in surface area and 0.1 cm3/g in pore volume. SGA has smaller silica primary particles (10–20 nm) with higher surface area (205.9 m2/g) and higher pore volume (0.70 cm3/g). When PSA and SGA hydrogels were aged at 110 °C, they transformed to a condensed silicagel adsorbent (C-SGA) with very low surface area (12.0 m2/g) and pore volume (0.05 cm3/g). ...

In order to study the effect of CO2 loading on the physical properties of non-aqueous organic solvents, the secondary amine diethanolamine (DEA) was studied in 1-Propanol. The effect was reported in terms of viscosity, density and CO2 loading; their trends were obtained based on timely basis. Three different concentrations of DEA in 1-Propanol were tested to show the effect of amine concentration on the measured properties. The considered concentrations were of 2, 3.5 and 5M at room conditions. All three concentrations showed solid formation beyond their maximum CO2 capacity where a biphasic behaviour was observed for 3.5 M and 5 M. Furthermore, the trend for the measured properties were of increasing pattern for all concentrations until the solid formation point, where after this point the readings fluctuated. All of the investigated concentrations showed losses that were ~11 w.t% of 1-Propanol. For comparison reasons, also 30 w.t% of aqueous DEA was studied in the same manner and better CO2 loadings were obtained for all the studied non-aqueous systems. The aqueous secondary amine showed a maximum loading of 31 (mg CO2/g sample) where the 2 M DEA in 1-Proponol showed a comparable maximum capacity of 35 (mg CO2/g sample) with the viscosity and density of 9.28 cP and 0.91 g/mL, respectively. It is noteworthy that this loading in the non-aqueous medium was obtained using a lower amount of DEA than in aqueous solution. Out of the three studied concentrations, the secondary amine DEA in 1-Propanol, showed leading results with the 3.5 M concentration, in which its viscosity was 35.68 cP for 74 (mg CO2/g sample) as a loading and 0.93 g/mL of density. It was observed that flowing CO2 beyond this point leads to solid formation within the 3.5 M solvent system; biphasic behaviour. With this, the 3.5 M system can be advised to be further studied for post-combustion CO2 capture.

Associated with the rise in energy demand is the increase in the amount of H2S evolved to the environment. H2S is toxic and dangerous to life and the environment, thus, the need to develop efficient and costeffective ways of disposing of the H2S gas has become all-important. To this end, a two-step thermochemical H2S splitting cycle is proposed in this work which does more than just getting rid of the toxic gas but has the potential to produce valuable H2 gas as well as store the solar heat energy. Studies have proved that the type of material used, such as metal sulfides, is critical to the efficiency of this thermochemical splitting process. As follows, this study focuses on establishing a criterion to aid in selecting favorable metal sulfides for application and further development in the H2S thermochemical decomposition sphere. Using a computational approach, via the HSC Chemistry 8®, evaluations such as the equilibrium yield from the sulfurization and decomposition reaction steps, the temperature required for reaction spontaneity, and the Reversibility Index were determined. Investigations proved that sulfides of Zirconium, Niobium, and Nickel were auspicious candidates for the thermochemical decomposition.

A thorough and comprehensive study of different parameters affecting the sorbents prepared by impregnating polyethyleneimine (PEI) on silica for CO2 capture has been conducted. The CO2 capture performances of resulting sorbents were evaluated on both packed-bed and fluidized-bed reactors. Obtained results indicated that CO2 adsorption-desorption performances of sorbents are greatly affected by the operation temperature in both simulated flue gas from coal fired power plant (SCF) and natural gas combined cycle power plant (NGCC). The optimal adsorption temperatures are from 50 to 80 °C for NGCC flue gas and from 70 to 90 °C for SCF flue gas, while the optimal regeneration temperatures are from 110 to 130 °C for both flue gas. Adsorbent containing 30 to 35 wt% PEI fluidized well with both simulated flue gas and steam. Results from this study revealed that PEI impregnated silica is a promising sorbents for CO2 capture process, using a fluidized-bed reactor, from both coal-fired power and natural gas combined cycle power plants.

In this study, activated carbons were synthesized from seeds of local date fruits in the United Arab Emirates (UAE) and investigated for carbon dioxide (CO2) adsorption. Activated carbon (AC) synthesis was completed by furnace activation in the temperature range (600, 700, 800, 900 °C) after infusion with chemical compounds. Two reagents (Potassium Hydroxide- KOH and Sulfuric acid- H2SO4) were mixed with the date seed samples in varying impregnation ratios (KOH- 3:1, 4:1, 5:1 and H2SO4- 0.5:1, 1:1, 2:1) and directly heated to activation wherein the removal of volatile matter content leads to formation of AC porous structure. The AC yield was found to be inversely proportional to the activating temperature and impregnating ratio. Characterization tests carried out include elemental analysis, nitrogen sorption isotherms to assess surface area and micropore volumes, and Fourier transform infrared spectra to identify structural changes in surface functional groups. Adsorption tests were conducted via a micro- reaction calorimeter using pure CO2 stream at atmospheric pressures and temperatures (20, 30, 40 °C). The sulfuric acid activated carbons showed better capture capability in the range 40–80 mgCO2/gAC while KOH- samples had low CO2 uptakes (

To use calcite mud waste generated from the paper production process, calcite mud was treated by calcination and then applied as a sorbent agent to remove phosphorus from an aqueous solution. The pre-treatment muds were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The effects of calcite mud with different calcination temperatures on phosphorus removal were investigated. Different sorbent dosages, contact times, and initial phosphorus concentration conditions were also studied to understand the phosphorus removal mechanism. The results show that phosphorus removal efficiency was increased by increasing the calcination temperature of the mud. The phosphorus removal efficiency over 10 min increased by 35%, 82%, 98%, and 100% with 4.5, 6.75, 9.0, and 11.25 mg, respectively, of calcite mud calcined at 1000 &deg, C. However, the efficiency decreased as initial phosphorus concentration increased. To study the phosphorus removal trend, the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models were used. The Langmuir and Freundlich isotherm models were also used to further investigate the phosphorus adsorption mechanism characteristics of the calcite mud.

Ru nanoparticles with a range size of 2∼6 nm are successfully immobilized on the surface of carbon nanotubes (CNTs) through liquid plasma reduction. The CNT-Ru nanohybrid exhibits an excellent catalyst for the redox reaction in dye-sensitized solar cells with the electrolyte of triiodide/iodide ions.

Conventional Solvay process, which utilizes CO2 to synthesize sodium carbonate, has been well-known for more than a century, but the only purpose of this process is to produce soda ash. Annually, significant amounts of CO2 are converted into soda ash using Solvay process; however, this conventional process does not sustain CO2 and waste cycle. Increasing the awareness of global warming and climate change linking to CO2 emission has pressured this industry to move for a more eco-friendly process that should exploit its potential for CO2 utilization and sequestration and thus contribute to both CO2 emission and waste management. In conventional Solvay process, to produce one mole of Na2CO3, at least one mole of CO2 might be emitted to atmosphere due to the use of CaO. Therefore, a number of studies have been done to explore novel processes or to modify the Solvay process in order for it to engage more in CO2 mitigation. This chapter introduces the most up-to-date modified Solvay process and novel pathways to produce soda ash and baking soda in the consideration of waste and CO2 utilization. Simultaneous waste and CO2 utilization offers a great opportunity for shifting to a green production, not only soda ash industry but others where their exhausted CO2, alkaline solid wastes, or reject brine can be utilized. However, there are challenges which require further research and technological development initiatives for the idea to be industrially implemented.

This study evaluated the feasibility of a chemical process which uses desalination brine to convert CO2 into useful sodium bicarbonate. The process is based on the integration of a modified Solvay process with conventional amine based post-combustion carbon dioxide capture for the simultaneous capture and conversion of CO2 into solid bicarbonates. A range of amine solvents were evaluated to select the most suitable solvent for the process. Then the effects of parameters such as temperature, brine concentration and amine concentration on the carbonation step of the process were evaluated. Moreover, different techniques for recovering the amine from the chloride rich solution were proposed and investigated. The sterically hindered amine, 2-amino, 2-methyl propanol (AMP), was found to be the best alcohol amine for the process and the CO2 absorption step was found to be significantly improved at lower temperatures, high brine concentrations and moderate amine concentration. For AMP, the optimum concentration was found to be 30 wt%. Finally, the amine recovery technique tested showed promise and could be optimized further to give better results.

Carbon dioxide post-combustion capture process using an aqueous solution of 30 wt% of monoethanolamine (MEA) is considered the most mature solution for CO 2 removal from bulk CO 2 gas streams. Although this amine based process is considered mature and has good performance characteristics such as good CO 2 absorption and high kinetics; it has high energy requirement which is approximately 3.6-4 GJ/ton of CO 2 . This high energy demand is the driving force behind the research activities seeking novel solvents with lower energy consumption. This work focuses on the thermodynamic and kinetics characterization of new amine-based solvents to evaluate their potential for CO 2 removal. A screening of different amines structure was done for the determination of the CO 2 loading by using solvent screening setup (S.S.S.) at 313.15K and a pressure of 1 bar containing 15%vol CO 2 and 85%vol N 2 . For the evaluation of the heat of absorption, a micro-reaction calorimeter was used at 313.15K and atmospheric pressure with pure CO 2 . The kinetics properties were obtained with stopped-flow equipment to measure the pseudo-first order reaction k 0 (s -1 ) at 298.15, 303.15, 308.15 and 313.15K. The results show that two tertiary amines, 2-(dimethylamino)ethanol (2DMEA) and 3-dimethylamino-1-propanol (3DMA1P), have high potential to blend with primary or secondary amine in order to improve the CO 2 loading, the heat of absorption and the reaction kinetics instead of using MDEA.

In this study, we report the effect of the moisture of polyethylenimine (PEI) impregnated mesoporous precipitated silica used for CO2 adsorption on the heat capacity and the heat required to regenerate the adsorbent. The results indicate that the heat capacity of the absorbent increases as its moisture content increases. The increase in moisture results in the rise of the vaporization heat of water and the elevated heat capacity results in higher sensible heat. For these reasons, the total regeneration heat required for CO2 capture process increases significantly. The adsorbent has a maximum CO2 adsorption capacity at 75 °C. CO2 capture process using PEI impregnated mesoporous precipitated silica requires a minimum energy to regenerate the adsorbent; it reduces 46% of the energy compared to a process using an aqueous MEA 30 wt%, as the process operates at 75 °C.

Agriculture in mountainous areas in Vietnam has much intensified since the introduction of market-based reforms in the mid 1980s. The adoption of hybrid maize varieties, mineral fertilizers and reduction in fallow periods has improved farm incomes, but has also led to a dramatic increase in soil erosion from sloping lands which has created a downward pressure on crop yields and has had adverse effects on downstream areas. This study explores the relationship between soil fertility, crop yields and the use of soil conservation methods by applying an agent-based modeling approach that combines whole-farm mathematical programming to simulate the decision-making of each individual farm household with a biophysical simulator of crop yields and soil fertility dynamics for each individual landscape unit. Simulation results suggest an average soil loss is 30 tons for maize fields and 27 tons for cassava fields per hectare per annum under present economic conditions, which is in the range of what other studies have measured, and a consequent decline in the average household incomes by 28.5% over a 25 years period. The introduction of three soil conservation methods in maize (vetiver grass strips, ruzi grass barriers and leucaena hedges) shows that these are not economical for farm households to adopt under present conditions, chiefly because of lower short-term maize yields. We explore the effect of giving farm households monetary incentives to adopt soil conservation and find that the payment needed for reducing 40 ± 2% of the estimated soil loss would be about 12–16 USD per ton of soil saved.

In this work the thermodynamic properties of monoethanlonamine (MEA), 3-piperidinemethanol (3PM) and their blends were measured and evaluated. The heat of absorption of the solution of CO 2 in the aqueous solution of single amines (5 M MEA,3 M MEA, 2 M MEA, 2 M 3PM and 3 M 3PM) and aqueous amine blends (2 M MEA+ 3 M 3PM, 3 M MEA + 2 M 3PM, 3 M MEA + 3 M 3PM) were measured isothermally using a commercially available micro-reaction calorimeter (μRC) at three different temperatures (313.15, 333.15 and 353.15) K and at different CO 2 loading capacity. The vapour liquid equilibrium apparatus was also used to obtain different samples of loaded CO 2 molCO 2 /molamine and their corresponding heat of absorption was measured using the micro-reaction calorimeter. In addition, the heat capacities of the above amines were also measured from 303.15 K to 353.15 K at an interval of 5 K. The calorimetric measurements of the heat of absorption at temperature (313.15 oK) indicated that the (3 M MEA + 2 M 3PM) blend has the lowest absorption enthalpy with 75.58 kJ/mol CO 2 at 0.56 molCO 2 /molamine (max loading capacity) than (5M-MEA) with a reported value of 87.827 kJ/molCO 2 at 0.51 molCO 2 /molamine which corresponds the maximum loading capacity of (5M-MEA). The (3 M MEA + 3 M 3PM) exhibited the lowest heat capacities among the measured blends of MEA and 3PM. 5 M MEA was used as a base case for all the experimental measurements for the heat of absorption.

In the present study, the potential for the use of different amines with desalination brines for the simultaneous capture and conversion of CO 2 into solid bicarbonates was evaluated. The focus of this work was to find the most suitable amine solvent for this proposed process. Various classes of amine solvents such as primary, secondary, tertiary and cyclic amines were identified and evaluated using the following parameters: Precipitate yield, CO 2 capacity and Sodium conversion. The results showed that bicarbonate salts of good purity can be synthesized by bubbling simulated flue gas into amine/brine solution. Also the sterically hindered amine, AMP, was found to be the best amine for the process due to its high precipitate yield and sodium conversion. Sodium removal above 80% was obtained when AMP was used. For all amines tested, the precipitated bicarbonate had a purity of over 95% while the CO 2 capacity varied, with Piperazine having the highest. The obtained results demonstrate that the proposed process is a promising technology for the simultaneous capture and utilization of CO 2 using desalination reject brine.

Silver nanoparticle (SNP)-containing ceramic filter (SNP-CF) has been widely investigated for water disinfection but the filters usually lose their antibacterial efficacy after short time because of silver leaching. In this study, the SNP-CF has been successfully prepared by an in-situ reduction method in which silver nitrate was first impregnated into activated carbon, which was then added into ceramic mixture for filter production. Silver nitrate in activated carbon got reduced to metallic silver by thermal treatment. Resulting filters were characterized by various techniques including saturated water method, nitrogen adsorption/desorption, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The utilization of activated carbon as filler produced ceramic filter with high porosity (64%) compared to charcoal (56%) and sawdust (29%), particularly, the porosity of activated carbon ceramic filter was not affected by the addition of SNPs. The SNP-CF having mesopores with pore diameter from 2 to 6 nm and pore volume of 0.02 cm3/g. The SNPs uniformly distributed throughout ceramic structure helps the filter constantly release silver for a long period. Silver concentrations detected in filtrate were 0.04 ppm for SNP-CF prepared by in-situ reduction (0.03 wt% silver) and 0.736 ppm for SNP-coated ceramic filter (0.03 wt% silver). The filter showed a great antibacterial activity with 100% of E. coli and coliform eliminated via filtration for extended period (10 weeks). The success of this work has proposed a novel and facile method to prepare SNP-CF that can be applied for water disinfection.

We studied the effects of various surfactants on the textural properties (BET surface area, pore size, and pore volume) of the silica aerogels prepared at an ambient pressure. A simple surface modification of silica gel prepared at an ambient pressure through hydrolysis and polycondensation of TEOS as a silica precursor was conducted using various structure directing agents. The treatment was found to induce a significant difference in the porosity of the silica aerogel. Highly porous silica aerogels with bimodal porous structures were prepared by modifying the surface of the silica wet-gel (alcogel) with trimethylchlorosilane (TMCS) in order to preserve its porosity. The samples were analyzed by small-angle X-ray scattering and nitrogen adsorption. In this work, a possible new type of highly porous hydrophobic silica aerogel with a bimodal porous structure is presented. A hydrophilic extremely porous (high surface area and large pore volume) silica aerogel was obtained by heating the as-synthesized hydrophobic silica aerogel at 400 °C for 1 h. There was a significant effect of structure directing agent on the textural properties, such as specific surface area, pore size distribution and cumulative pore volume of the silica aerogels.

Aggregation state of silver nanoparticles dispersed in an aqueous solution greatly varies with storage and treatment conditions. In this study, silver nanoparticles synthesized in chitosan solution by a chemical reduction method were hydrothermally treated at different temperatures. The variation in the aggregation state of silver nanoparticles in the solution was observed by UV-Vis spectroscopy and field emission transmission electron microscopy. Results indicated that a phase transition occurred while silver nanoparticles were hydrothermally treated for 5 h at 100 and 120∘C; however, they aggregated and completely precipitated at 150∘C. Mesoporous silver powder obtained by hydrothermal treatment at 150∘C was characterized by using X-ray diffraction technique, BET analyzer, and scanning electron spectroscope.

Soil degradation is an environmental process mainly caused by land use decision-makers that has substantial feedback effects on livelihoods and the environment. To capture these feedback effects and the resulting human-environment interactions, we used an agent-based modeling approach to couple two software packages that simulate soil, water and plant dynamics (LUCIA), and farm decision-making (MP-MAS). We show that such a software coupling approach has advantages over hard-coded model integration as applied by most other comparable studies, as it facilitates combining of increasingly sophisticated individual models and can achieve a well-balanced representation of agricultural systems. Using a numerical application for a small mountainous watershed in northwest Vietnam we show the challenges in model coupling, calibration and partial validation, and explore the properties of the coupled model system. Scenario analysis covering the introduction of low-cost soil conservation techniques indicates that some of these techniques would have an impact on soil erosion, maize productivity and household income levels in the study catchment area under current conditions. However, maize yields and the adoption of soil conservation appear to be sensitive to the price of mineral fertilizers, with lower fertilizer prices impeding the adoption of soil conservation measures. The software coupling approach was able to capture interactions between decision-makers and natural resources, as well as the level of spatial variability, in more detail than the individual models. Still, the greater number of endogenous variables and thus degrees of freedom increased the importance of validation and testing parameter sensitivity of the results.