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This study evaluated the feasibility of low-cost nanoporous catalysts, such as dolomite and red mud, on the production of aromatic hydrocarbons via the catalytic pyrolysis of polyethylene terephthalate (PET). Compared to the non-catalytic pyrolysis of PET, catalytic pyrolysis over both dolomite and red mud produced larger amounts of aromatic hydrocarbons owing to their catalytic cracking efficiency and decarboxylation efficiency. Between the two catalysts, red mud, having a larger BET surface area and higher basicity than dolomite, showed higher efficiency for the production of aromatic hydrocarbons.

This study focuses on analyzing the effects of the SiO2/Al2O3 ratio of a support on the physico-chemical properties of bead-type CoMo/HZSM-5 catalysts and on the catalytic performance during the hydrocracking reaction of PFO. CoMo/HZSM-5 catalysts were prepared by an incipient wetness method. Subsequently, binder-added catalysts were molded into the bead type catalysts. The N2 adsorption-dersorption results clearly indicate that the nanoporous structure was well developed in the bead-type CoMo/HZSM-5 catalyst. The CoMo/HZSM-5(30) catalyst not only possessed the highest number of acid sites but also showed the highest ratio of strong acid to weak acid sites. Moreover, the Lewis acid/Brönsted acid site ratio is highest with the CoMo/HZSM-5(30) catalysts. A hydrocracking reaction of PFO over the bead-type CoMo/HZSM-5 catalysts was conducted at 400 °C and under 40 atm in a fixed-bed reactor. The bead-type CoMo/HZSM-5(30) catalyst showed the highest BTXE yield with a sum of BTXE outcome of 43.0% in the catalytic cracking reaction of PFO, which is attributed to the synergistic combination of suitable acidity and hierarchical porosity.

The demand for alternative energy is increasing rapidly because of global warming and the depletion of fossil fuels. Gasification is a technology that produces gaseous fuels through the incomplete combustion of waste or biomass. The introduction of a catalyst during gasification may increase the production of H2 and reduce tar formation. In this study, the catalytic gasification of rice hulls was carried out using a fluidized gasifier. To improve the gas yield and reduce tar, municipal solid waste incineration bottom ash (IBA) having nanoporosity was introduced as a substitute for the fluidized bed material. Gasification was carried out at 800 °C, and the flow materials were silica sand, dolomite, and incineration bottom ash. The equivalence ratio, which is the ratio of oxygen supplied to oxygen required for complete combustion, was set to 0.3. The application of alternate fluidized bed materials (dolomite and incineration bottom ash) was effective in improving the hydrogen yield and tar reduction. This was attributed to the high Ca and Mg contents in dolomite and incineration bottom ash. Therefore, it is expected that IBA can be utilized as a catalytic fluidized bed material to replace silica sand.

The objective of this study is to evaluate the catalytic performance of pellet-type Ru/γ-Al2O3 as a catalyst during liquid-phase hydrogenation of the aromatic hydrocarbon. The Ru/γ-Al2O3 catalyst was prepared using a wet impregnation method. After adding a binder to Ru/γ-Al2O3, a pellet-type catalyst was obtained through an extrusion method. Nanoporous structures are well developed in the pellet-type Ru/γ-Al2O3 catalyst. The average pore sizes of the Ru/γ-Al2O3 catalysts were approximately 10 nm. The catalytic performance of the pellet-type Ru/γ-Al2O3 catalyst during ethylbenzene hydrogenation was evaluated in a trickle-bed reactor. When the ruthenium loading increased from 1 to 5 wt%, the number of active sites effective for the hydrogenation of ethylbenzene increased proportionally. In order to maximize the conversion of ethylbenzene to ethylcyclohexane, it was necessary to maintain a liquid phase hydrogenation reaction in the trickle bed reactor. In this regards, the reaction temperature should be lower than 90 °C. The conversion of ethylbenzene to ethylcyclohexane on the Ru(5 wt%)/γ-Al2O3 catalyst was highest, which is ascribed to the largest number of active sites of the catalyst.

The complete oxidation of toluene (as a model volatile organic compound) was studied to determine the influence of adding a transition metal (Mn, Cr, Fe, Co, and Ni) to the 5 Cu/Al catalyst. The physcochemical properties of the catalysts were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD) analysis, field emission transmission electron microscopy (FE/TEM), and hydrogen temperature programmed reduction (H2-TPR). The catalytic activity of the supported bimetallic catalysts followed the order: 5Cu-5Mn/Al > 5Cu-5Cr/Al > 5Cu-5Fe/Al > 5Cu-5Co/Al > 5Cu > 5Cu-5Ni/Al, based on the temperature for T90 of toluene conversion (T90). Two different reaction mechanisms (mixing and the synergistic effect) were operative in the supported bimetallic catalysts except for the 5Cu–5Mn/Al and 5Cu–5Ni/Al catalysts, on the basis of the reaction temperature. The difference between the electronegativity of copper and the added transition metal was associated with the catalytic activity.

In this study, molybdenum oxide/carbon nanocomposites (MOCNCs) were prepared by precipitating molybdenum oxide nanoparticles on activated carbon powder using liquid phase plasma process. The molybdenum oxide nanoparticles were impregnated on the AC surface and the amount impregnated was dependent on the concentration of the molybdenum precursor. MoO3 nanoparticles were predominantly precipitated and their size was about 20–80 nm. The specific capacitance of MOCNCs was increased with increasing the amount of molybdenum nanoparticles. Moreover, the resistances of MOCNCs were reduced than that of bare AC.

The activity of Ni silicates having different Ni/Si molar ratio (0.5 and 1) and Ni/silica were tested on biomass gasification. Ni silicate (Ni/Si= 0.5) and Ni/silica produced the higher gas yield than Ni silicate (Ni/Si = 1.0). The larger amount of H2 and CO were produced over Ni silicate (Ni/Si = 0.5) and Ni/silica compared those over Ni silicate (Ni/Si = 1.0). The catalysts were characterized using BET and XRD analysis. Ni silicate (Ni/Si = 0.5) showed promising activity for the production of syngas at higher temperature and can be employed in gasification.

The catalytic oxidation of benzene and toluene (VOCs) was carried out in order to assess the properties and catalytic activities of spent vanadium-based catalyst and that modified with copper and manganese. The properties of the prepared catalysts were characterized by the Brunauer Emmett Teller (BET) surface area method as well as X-ray diffraction (XRD), Attenuated total reflection-Fourier transform infrared (ATR-FTIR), and Scanning electron microscopy-Energy dispersive X-ray (SEM-EDX) analyses. The experimental results showed that oxalic acid treatment significantly affected the activity of the spent vanadium-based catalyst, ultimately attributing to the removal of catalyst poison such as sulfur and the even redistribution of catalyst components. Moreover, the addition of copper or manganese to the spent vanadium base catalyst treated with oxalic acid (SVO) enhanced its catalytic activity.

The HDO reaction was carried out using anisole at 300 °C in hydrogen under atmospheric pressure. Ni/meso-SiO2 and Nickel silicate catalysts with high nickel contents were used. The yield of hydrocarbons in the HDO reaction over the nickel silicate catalyst was high compared to that over the Ni/meso-SiO2 catalyst. In addition, the stability of the nickel silicate catalyst was excellent.

Hydrodeoxygenation (HDO) reactions under low/atmospheric pressure of hydrogen should be studied to solve the problem of the economics of the high-pressure hydrogen upgrading process. Therefore, in this study, the catalytic HDO reaction of m-cresol in atmospheric hydrogen pressure was evaluated using Ni/silica and Nickel silicate (Ni-MCM-41) catalysts. The Ni-MCM-41 catalyst exhibited higher conversion of m-cresol than Ni/silica. The high activity of the Ni-MCM-41 catalyst was due to the large specific surface area and the high nickel loading.

The desilication effect of Beta on the catalytic pyrolysis of polyethylene terephthalate (PET) was investigated in this study. Compared to parent Beta, desilicated Beta revealed the higher aromatics formation efficiency due to its larger pore size allowing the efficient diffusion of PET pyrolysis intermediates to the catalyst pore. Compared to the in-situ catalytic pyrolysis, ex-situ catalytic PET pyrolysis over desilicated Beta produced a larger amount of aromatics. The desilicated catalyst could be re-used without catalyst regeneration due to the small extent of catalyst deactivation.

The aim of this study is to elucidate the influence of an iridium loading strategy over hexaaluminate on the catalytic performance during the decomposition of liquid monopropellants based on ammonium dinitramide (ADN). Powder-type and pellet-type Ir/hexaaluminate catalysts were prepared and their chemico-physical properties were characterized by N₂ adsorption, XRD, XRF, and SEM. There were considerable differences in the Ir amounts present on the surface according to the impregnation method employed. The catalytic activities of three types of Ir/hexaaluminate catalysts to decompose the ADN-based liquid monopropellant were compared using a semi-batch type of reactor. Pellet-type Ir/hexaaluminate catalyst, which formed hexaaluminate into a pellet and where iridium was impregnated during the last stage, showed the lowest onset temperature during the decomposition of the ADN-based liquid monopropellant, having the effect of lowering the decomposition onset temperature by around 60 °C compared to that without a catalyst. This was due to the pellet-type Ir/hexaaluminate having a larger surface area and a large number of Ir active sites on its surface.

Catalytic combustion of benzene, toluene, and hexane (BTH) was carried out to investigate in this study the effect of palladium precursor on the property and performance of 1 wt.% Pd/γ-Al₂O₃. Properties were characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET) surface area, temperature programmed reduction (TPR), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses. When palladium precursor was used to prepare the catalyst, it had a great effect on the property and performance of the supported palladium catalyst. Total acidity, size of palladium particle, and oxidation state of palladium were associated with catalytic activity of the catalyst. Higher total acidity of the catalyst and larger particle size of palladium favorably affected the catalytic activity. In addition, palladium species with high oxidation state might be useful to increase catalytic activity in BTH combustion.

Lignocellulosic biomass, principally consisting of cellulose, hemicellulose and lignin, is a main renewable source for the production of biofuels and valuable chemicals. For instance, the polyaromatic structure of lignin fraction of biomass makes it a high potential feedstock for the production of valuable aromatic chemicals such as phenolic compounds. In this work, selective conversion of the organosolv lignin-derived pyrolyzates to alkylphenols was carried out using Ce-MCM-41 as In-Situ catalyst. Catalytic fast pyrolysis of the organosolv lignin was carried out on a tandem micro-pyrolyzer coupled with gas chromatography and mass spectrometry (GC-MS) detectors. The refined pyrolytic vapor was mainly consisting of phenolics (phenol, alkylphenols, guaiacol and alkylguaiacols), monoaromatic hydrocarbons (benzene, toluene and xylenes), esters (formic acid ethyl ester, acetic acid methyl ester and hexadecanoic acid methyl ester), aldehydes (formaldehyde and methylbenzaldehyde), acids (hydroxyacetic acid and benzoic acids), furans (2-methylfuran and dihydrofuran) and ethanol. Our data showed that the selectivity of products was influenced by pyrolysis temperature (500, 550 and 600 °C). Maximum selectivity of alkylphenols (10.3%) was obtained at 550 °C. Besides In-Situ pyrolysis of organosolve lignin, the In-Situ upgrading of the cellulose-derived pyrolyzates was carried out using Ce-MCM-41 at 550 °C. In-Situ pyrolysis of cellulose using Ce-MCM-41 could obtain high selectivity of aldehydes (11.4%), furans (9.6%) and ketones (3.2%).

Catalytic hydrodeoxygenation (HDO) of cork oak pyrolysis oil was performed using a high pressure batch type reactor. Cork oak pyrolysis oil, obtained from the fast pyrolysis of cork oak, was upgraded into high quality oil under HDO conditions (260 °C, 80 bar) over 20 wt.% Ni/Al-MCM-41. Compared to the cork oak pyrolysis oil, HDO oil had a smaller oxygen content, increased heating value, and improved viscosity and acidity due to the high contents of esters and hydrocarbons.

Ni/spent FCC catalyst was applied as the catalyst on the catalytic pyrolysis and gasification of yellow poplar (YP). Larger amount of gas (CO, CO₂, H₂, C1~C₄) was produced by applying Ni/spent FCC catalyst to the catalytic pyrolysis and gasification of YP. Ni/spent FCC catalyst also increased the selectivity of phenols and aromatic hydrocarbons in oil product during the pyrolysis and gasification of YP. Overall catalytic performance of Ni/spent FCC catalyst was similar level with that of Ni/γ-Al₂O₃, suggesting its potential use.

Chromium oxide/carbon nanocomposites (COCNC) were synthesized by using a liquid phase plasma process, and the electrical properties of the supercapacitor electrode were investigated. Spherical chromium oxide (Cr₂O₃) nanoparticles with the size of 100-150 nm were dispersed uniformly on activated carbon powder surface. The quantity of chromium oxide nanoparticle precipitate increased with increasing LPP reaction time and the specific capacitance of COCNC increased with increasing LPP reaction time.

Desilicated Beta (DeBeta) was applied as the catalyst to the catalytic pyrolysis of waste lignin for the formation of aromatic hydrocarbon, and its performance was compared with that of the unmodified Beta. Large amounts of oxygen containing pyrolyzates were efficiently converted to stable aromatic hydrocarbons over both Beta and DeBeta catalysts. Compared to Beta, DeBeta exhibited the higher performance for the formation of aromatic hydrocarbons due to the enhanced diffusion efficiency through the mesopore.

Catalytic pyrolysis oil (CPO) was produced from lignin using the ex-situ mechanism and nanoporous HZSM-5 (SiO2/Al2O3 = 50) as a catalyst. The oil contained phenolics, esters, acids, and benzene derivatives as the major constituents. The emulsification of CPO in diesel was tested with several emulsifier combinations such as Span 80 and Tween 60, Span 80 and Atlox 4916, and Atlox 4916 and Zephrym PD3315 in the HLB range of 5.8–7.3. The HLB value of 5.8 using the combination of Span 80 and Atlox 4916 and the CPO:emulsifier:diesel ratio of 5:2:93 (wt%), provided a stable emulsion for 10 days. The physiochemical properties of that emulsion were comparable to diesel. Hence, emulsions of CPO and diesel can potentially be used as a diesel engine fuel.

In this study, the effect of Ru-Mn bimetallic catalysts in combination with a zeolite support on the removal of toluene in the presence of ozone at room temperature was investigated. Desili-cated HZSM-5 (DZSM) was fabricated and applied as a Ru-Mn support for the removal of toluene (100 ppm) in the presence of ozone (1000 ppm) at room temperature. The surface area, pore volume, and average pore size of Ru-Mn with a DZSM support (RuMn/DZSM) were measured and compared with those of Ru-Mn/HZSM-5 (RuMn/HZSM). The pore size of RuMn/DZSM (69 Å) was much larger than that of RuMn/HZSM-5 (5.5 Å). In addition, the pore volumes of RuMn/DZSM and RuMn/HZSM were 0.64 and 0.25 cm3/g, respectively. Furthermore, the ratios of Mn3+/Mn4+ and Ovacancy/Olattice of RuMn/DZSM were larger than those of RuMn/HZSM-5. The removal efficiency of toluene of RuMn/DZSM was higher than that of RuMn/HZSM due to its larger pore volume, pore size, and the increased ratios of Mn3+/Mn4+ and Ovacancy/Olattice.

This study examined the catalytic effects of Al-MCM-41 on the pyrolysis of wood plastic composite via the thermogravimetric analysis (TGA) and model-free kinetic analysis. Al-MCM-41 containing nanopores, with a high BET surface area (633 m2/g) and acidity (SiO2/Al2O3:25), reduced the decomposition temperature of wood and plastic mixtures (PE and PP) in a wood-plastic composite. The average activation energy for the catalytic pyrolysis of wood plastic composite, which was calculated via a model-free kinetic analysis method (Ozawa) of TGA, was also lower at all conversions than those of non-catalytic pyrolysis. This suggests that the pores of Al-MCM-41 and its high cracking efficiency allow the effective diffusion of wood plastic composite components.

The objective of this study is to evaluate the catalytic performance of pellet-type Ru/γ-Al₂O₃ as a catalyst during liquid-phase hydrogenation of the aromatic hydrocarbon. The Ru/γ-Al₂O₃ catalyst was prepared using a wet impregnation method. After adding a binder to Ru/γ-Al₂O₃, a pellet-type catalyst was obtained through an extrusion method. Nanoporous structures are well developed in the pellet-type Ru/γ-Al₂O₃ catalyst. The average pore sizes of the Ru/γ-Al₂O₃ catalysts were approximately 10 nm. The catalytic performance of the pellet-type Ru/γ-Al₂O₃ catalyst during ethylbenzene hydrogenation was evaluated in a trickle-bed reactor. When the ruthenium loading increased from 1 to 5 wt%, the number of active sites effective for the hydrogenation of ethylbenzene increased proportionally. In order to maximize the conversion of ethylbenzene to ethylcyclohexane, it was necessary to maintain a liquid phase hydrogenation reaction in the trickle bed reactor. In this regards, the reaction temperature should be lower than 90 °C. The conversion of ethylbenzene to ethylcyclohexane on the Ru(5 wt%)/γ-Al₂O₃ catalyst was highest, which is ascribed to the largest number of active sites of the catalyst.

In this study, the physicochemical properties of modified biochar using different methods, such as physical (CO2, steam) and chemical (KOH and H3PO4) methods, were estimated by X-ray diffraction, N2 adsorption-desorption, field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The performance of chars was evaluated using a Cr adsorption performance test. Among various chars modified in this study, CHC-P modified by H3PO4 showed the highest chromium adsorption efficiency. The adsorption efficiency was affected by the high nano-porosity, large surface area, and surface oxygen-containing functional groups.

This study examined the thermal and catalytic pyrolysis of waste

The effect of seawater aging on the thermal and catalytic pyrolysis of polypropylene (PP) was investigated using a thermogravimetric analyzer and pyrolyzer-gas chromatography/mass spectrometry. Although the surface properties of PP were of the oxidized form by seawater aging, the decomposition temperature and non-catalytic pyrolysis products of PP were relatively unchanged largely due to seawater aging. The catalytic pyrolysis of seawater-aged PP over all the catalysts produced smaller amounts of aromatic hydrocarbons than that of fresh PP due to catalyst poisoning caused by the residual inorganics. Among the catalysts, microporous HZSM-5 (SiO2/Al2O3:23) produced the largest amount of aromatic hydrocarbons followed in order by microporous HY(30) and nanoporous Al-MCM-41(20) from seawater-aged PP due to the high acidity and appropriate pore size for the generation of aromatic hydrocarbons.

The change in the crystallinity of Ce–Ti oxide nanocatalysts with different water contents was investigated in terms of the local atomic structure and the surface atomic concentration. The crystallization of TiO2, which was induced by the hydrolysis of the Ti precursor, was observed in the catalyst synthesized via a liquid phase reaction employing a mixture of ethanol and distilled water as the solvent. The hydrolysis reaction of the Ti precursor was impeded in the solvent mixture of ethanol and anhydrous ethanol. CeO2 nanocrystallization occurred due to the suppression of the TiO2 crystal growth. Low crystallinity of the catalyst synthesized in a single anhydrous ethanol solvent was observed through the broadened X-ray diffraction (XRD) peak and the diffused ring pattern in transmission electron microscopic (TEM) images. In addition, the Ce–O and Ce–Ce bond lengths of the catalyst synthesized using the single solvent decreased beyond those of the catalysts synthesized in the mixed solvent, indicating the amorphization of the catalyst. It was also verified that the inhibition of the precursor crystallization during the synthesis led to the enhanced dispersion of the nanocatalyst, compared to the stoichiometry of the surface atomic concentration.

A facile coagglomeration method for preparing a long alkyl chain modified graphene oxide (MGO)/MgCl2-supported Ti-based Ziegler-Natta catalyst was reported. The effects of MGO on the catalyst morphology and activity for ethylene polymerization were examined. The resultant polyethylene (PE)/MGO nanocomposites exhibited a layered morphology, with the MGO fillers being well dispersed and exhibiting strong interfacial adhesion to the PE matrix. The thermal stability and mechanical properties of the PE were significantly enhanced with the introduction of a small amount of the MGO filler. Thus, this work provides a facile approach to the production of high-performance PE.

Zinc oxide/activated carbon nanocomposites were synthesized by impregnating zinc oxide nanoparticles onto activated carbon powder using liquid phase plasma (LPP) method. Zinc oxide nanoparticles on the surface of activated carbon were fabricated rapidly by the LPP method due to reducing the zinc ion in aqueous solution. The obtained zinc oxide/activated carbon nanocomposites were characterized by XPS, HRTEM, and EDS. The amount of zinc oxide nanoparticles impregnated increased with increasing initial precursor concentration. Approximately 150~300 nm sized spherical shaped nanoparticles were uniformly dispersed on the surface of activated carbon powder.

The catalytic pyrolysis of waste Korean pine nut shell (KPNS) over mesoporous Al2O3 was investigated by thermogravimetric analysis (TGA) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). TGA results showed that the thermal and catalytic pyrolysis of KPNS over mesoporous Al2O3 has the same decomposition temperature. On the other hand, the maximum decomposition for the catalytic pyrolysis of KPNS over commercial-Al2O3 shifted to a higher temperature. The Py-GC/MS results indicated that large amounts of oxygen-containing pyrolyzates, such as acids, furans, levoglucosan, and phenols, were produced by the non-catalytic pyrolysis of KPNS. These oxygen-containing pyrolyzates were upgraded efficiently into aromatic hydrocarbons by applying Al2O3 catalysts. Between the two Al2O3 catalysts, mesoporous Al2O3 showed better performance on the formation of aromatic hydrocarbons via the catalytic pyrolysis of KPNS than commercial Al2O3 because of its uniform larger pores.

The estrogenicity of octyl glucoside was studied with its preparation method using microporous zeolites. Its estrogenicity was estimated using E-assay method to confirm the possibility as non-endocrine disruptive surfactant. The octyl glucoside was synthesized from D-glucose with 1-octanol by direct glucosidation. The high conversion of D-glucose was obtained on H-FAU zeolite which has a mild acid strength. The conversion and yield were improved with increasing of acid site amount of the zeolite catalysts. The octyl glucopyranoside is more hydrophilic than nonylphenol and has a high wettability. The octyl glucosides represented extremely lower estrogenic cell proliferation compared with nonylphenol.

Catalytic oxidation of toluene was carried out to investigate the effect of consecutive run on the catalytic property and performance of 1 wt.% Pt/γ-Al2O3 and the reduced 1 wt.% Pt/γ-Al2O3. The properties were characterized by X-ray diffraction (XRD), the Brunauer Emmett Teller (BET) surface area, temperature programmed reduction (TPR), and transmission electron microscopy (TEM) analyses. In consecutive experiments the second catalytic run resulted in a significant increase of the toluene conversion compared to the first catalytic run, but the toluene conversion in the third catalytic run was similar to that of the second catalytic run. In addition, the reducing treatment of the catalyst led to an increase in the catalytic activity. The increasing catalytic activity in consecutive runs was dependent on the platinum particle size and the oxidation state of the platinum. The increase in platinum particle size during reaction and the reduction in the oxidation state of platinum by hydrogen pretreatment were responsible for the increase in the catalytic activity.

The liquid phase plasma (LPP) synthetic process has been exploited to synthesize nickel oxide nanoparticles doped TiO2 photocatalyst (NOTP) that can respond to visible light. The physicochemical properties of NOTPs were studied by several analysis instruments. The nickel oxide nanoparticles precipitated uniformly on the TiO2 powder are mostly NiO. The band gap energy of the NOTP measured was 2.99 eV, which was smaller than that of bare TiO2, 3.12 eV. The NOTP synthesized in this work showed high photoactivity under visible blue light.