Anthropogenic gas of CO2 level was higher than CO2 atmospheric safety limit of 350 ppm since 80’s. It can be assumed that CO2 level growth directly proportional to the population and development. Hence, studies on CO2 capture have been extensively established in between year of 2000-2010. Metal oxide can be a good adsorbent but it has the weakness in surface area and sintered after regeneration process. Thus, activated carbon was used to enhance the surface area which mainly responsible for physical adsorption. Fe2O3 supported on activated carbon (Fe2O3/AC) were prepared by impregnation method and used for CO2 adsorption-desorption studies. The XRD result shows that precursor of ferric nitrate used to impregnated on AC (activated carbon) support was directly dissociated to Fe2O3 metal oxide by thermal treatment under N2 atmosphere temperature at 450 °C. The loading amount of Fe2O3 by weight ratio affect the textural properties and CO2 capturing capacity. The surface area and pore volume of the catalyst decrease with the loading of Fe2O3. Highest Fe2O3 loading shows greater amount chemically adsorbed of CO2. Nevertheless, it drastically reduced the surface area of the AC, which is chiefly responsible for CO2 physisorption, thus decreasing the carrying capacity of ACs at 25 °C. The 20Fe2O3/AC was found to be optimum loading for better physi and chemisorptions of CO2.
Abstract. Silica dioxide catalyst (SiO 2 ) can be modified by impregnating amine-containing compounds to improve the CO 2 adsorption capacity. Four type of amines, i.e., monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA) and octadecylamine (ODA) were supported on silica dioxide particles. The amine-modified samples were characterized using FTIR, BET and FESEM. All the prepared solid sorbents exhibited type IV isotherm with hysteresis loop. Specific surface areas of the sorbents were significantly reduced due to blocking of micropores and mesopores by the amine compounds. Reactivity of solid sorbents towards CO 2 was evaluated using isothermal CO 2 adsorption by BET. CO 2 adsorption capacity increased with the weight percent of amine compounds loaded onto the SiO 2 . 15 and 25 wt % MEA/SiO 2 and 25 wt % ODA/SiO 2 sorbents showed greater CO 2 adsorption capacities compared to the virgin sample (SiO 2 ). This study shows that the order of adsorption capacity for the four types of amines was MEA (4.05 wt % CO 2 /adsorbent) > ODA (2.45 wt % CO 2 /adsorbent) > DEA (1.71 wt % CO 2 /adsorbent) > TEA (0.91 wt % CO 2 /adsorbent). CO 2 uptakes by ODA/SiO 2 sorbents were higher than DEA/SiO 2 and TEA/SiO 2 is mainly due to their smaller pore volume and pore width of the adsorbent, therefore, greater interactions of CO 2 -ODA in pores. MEA/SiO 2 has the highest ability in capturing CO 2 because of the increasing steric hindrance of long chain ODA and alkyl substituent on DEA and TEA.
The priority of success in practical CO2 capture with solid sorbents is dependent on the development of a low cost sorbent and energy consumption for regeneration with high adsorption capacity. In this work, different loading of NiO were evaluated as a potential source of basic sites for CO2 capture, and activated carbon (AC) was used as a preliminary support in order to study the effect of the impregnation. The NiO loading increased the basicity of the adsorbent significantly enhance the CO2 chemisorption. Nonetheless, it drastically reduced the surface area of the AC, which is chiefly responsible for CO2 physisorption, thus decreasing the carrying capacity of ACs at room temperature and pressure.
Porous surface of silica gel (SG) have been modified with long and straight chain fatty amine compounds (octadecylamine, ODA) via wet impregnation process. SG was undergo heat treatment with various temperature which are 100, 200, 400 and 600 °C before continuing with impregnation process. Characterization by XRD of the treated samples were showed no significant different in their diffractograms. The best temperature for heat treatment was 600 °C and it was referred to the ability of the SG600 type adsorbents in adsorbing CO2 resulted from adsorption desorption isotherm of CO2. The 5 and 35 wt. % of ODA supported on the SG (ODA/SG600) was further characterized using XRD analysis which displayed the increasing intensity of crystalline ODA with higher percent amine loaded and shifting of the several crystalline peak of ODA verified the interaction of SG600-ODA. These further strengthen the prevailing dispersion of ODA on the surface of SG600.
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