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RISS 인기검색어
- 검색키워드
- 저자 : Maedeh Mohammadi (검색결과 4 건)
- 무료
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Munirah Md Zain,Maedeh Mohammadi,Naoto Kamiuchi,Abdul Rahman Mohamed 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.10
This study explored the potential of In2O3/ZrO2 catalyst for direct CO2 hydrogenation to methanol. Despite the excellent properties proven by density functional theory (DFT) studies, the experimental works on this catalyst are still very limited. In this study, In2O3/ZrO2 catalysts were synthesized via wetness impregnation (In2O3/ZrO2(WI)), citric acid-based sol-gel method (In2O3/ZrO2(SG)) and deposition-precipitation assisted by urea hydrolysis (In2O3/ZrO2(UH)). Results indicated the impressive effect of preparation method on the catalytic activity where In2O3/ZrO2(SG) presented superior catalytic performance, followed by In2O3/ZrO2(UH) and In2O3/ZrO2(WI), with the CO2 conversion of 16.23%, methanol selectivity of 94.39% and STY of 0.95 gmethanol/gcat·h. To unravel the structure-function relationship, several characterization techniques including XRD, HR-TEM, SEM-EDX, H2-TPR, CO2-TPD, N2 adsorption-desorption isotherm and XPS were implemented to analyze the developed catalysts. The analyses indicated that the excellent performance of In2O3/ZrO2 (SG) was due to its smaller crystallite size, strong metal-support interaction, high reducibility and high concentration of basic sites and oxygen vacancies on the catalyst surface. Time-on-stream stability test showed that In2O3/ZrO2 (SG) catalyst could sustain its high activity and selectivity within 100 h, signifying the high potential of this catalyst for direct hydrogenation of CO2 to methanol with minimum side reactions and deactivation.
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Kasra Pirzadeh,Ali Asghar Ghoreyshi,Mostafa Rahimnejad,Maedeh Mohammadi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.4
The electrochemical route is a promising and environmentally friendly technique for fabrication of metal organic frameworks (MOFs) due to mild synthesis condition, short time for crystal growth and ease of scale up. A microstructure Cu3(BTC)2 MOF was synthesized through electrochemical path and successfully employed for CO2 and CH4 adsorption. Characterization and structural investigation of the MOF was carried out by XRD, FE-SEM, TGA, FTIR and BET analyses. The highest amount of carbon dioxide and methane sorption was 26.89 and 6.63 wt%, respectively, at 298K. The heat of adsorption for CO2 decreased monotonically, while an opposite trend was observed for CH4. The results also revealed that the selectivity of the developed MOF towards CO2 over CH4 enhanced with increase of pressure and composition of carbon dioxide component as predicted by the ideal adsorption solution theory (IAST). The regeneration of as-synthesized MOF was also studied in six consecutive cycles and no considerable reduction in CO2 adsorption capacity was observed.
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Low temperature adsorption of nitric oxide on cerium impregnated biomass-derived biochar
Shahreen Izwan Anthonysamy,Pooya Lahijani,Maedeh Mohammadi,Abdul Rahman Mohamed 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1
This study investigates the catalytic oxidation of NO to NO2 over biomass-derived biochar at ambient temperature. Rubber seed shell (RSS) was used as lignocellulosic waste to develop biochar for NO capture. The NO adsorption capacity of pristine biochar was low, about 17.61mg/g at 30 oC. To enhance the NO uptake capacity of biochar, cerium (Ce) was introduced into the biochar surface through simple impregnation method. Upon this, the NO adsorption capacity of 3 wt% Ce-loaded biochar profoundly increased to 75.59mg/g at the same adsorption condition. This was confidently due to the excellent oxygen storage capacity of ceria which could react with free active sites on the biochar surface to form oxidized cites C(O). Characterization results indicated that the adsorbed species was in the form of -O-N=O, suggesting that the adsorption of NO was followed by reaction with surface oxidized sites to form NO2. Studying the kinetics of the NO adsorption using pseudo-second order, Avrami and Elovich models showed that chemisorption was the chief mechanism that governed the adsorption process and the activation energy for NO adsorption was estimated to be around 45 kJ/mol.
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Removal of melanoidin from molasses spent wash using fly ash-clay adsorbents
Ali Ramezani,Ghasem Najafpour Darzi,Maedeh Mohammadi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4
Removal of melanoidin pigment from molasses spent wash was investigated using a new adsorbent. Solid adsorbents were fabricated from charcoal fly ash and clay. The effect of various molasses concentration (6 to 12 g/l)on removal efficiency was studied. The obtained results revealed that maximum removal efficiency of 82% was achieved at the molasses concentration of 6 g/l and contact time of 7 h. The saturated porous adsorbents were regenerated and reused to conduct similar experiments. The achieved data showed that more than 90% of the capacity of the fresh adsorbent was recovered after regeneration. Various adsorption isotherms of Langmuir, Freundlich, Temkin and Harkins-Jura were applied to interpret the obtained experimental data. The obtained results revealed that the sorption data were well described by the Harkins-Jura model. Also, various kinetic models of pseudo-first order, pseudo-second order,Elovich and intra-particle diffusion were used to predict the characteristic parameters which are useful in process design. It was concluded that the best fit was obtained with pseudo-second order kinetic model at low molasses concentrations.
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