In this work, zeolite-based sorbents were developed from gasified rice husk. CO2 capture capacity of the sorbents was examined at various temperatures and pressures employing a fixed-bed flow reactor and simulated flue gas. Various physicochemical properties such as thermal stability, pore size distribution, morphology, chemical composition, etc. of the in-house-developed materials were characterized in detail and were also compared with two commercially available zeolites. Tetra-ethylenepentamine was impregnated in the in-house-developed zeolite supports to investigate its suitability to improve the CO2 adsorption capacity. The effects of reactor pressure, temperature, Si/Al ratio, and amine loading on CO2 uptake capacity were examined. A declining trend in CO2 adsorption capacity was observed with the increase in adsorption temperature and amine loading. At 30 °C, zeolite-Y (designated as Z-Y-3, silica to alumina ratio of 2.25) sample exhibited maximum adsorption capacity, and the obtained values were around 114 and 190 mg CO2/g sorbent under atmospheric and 5 bar pressure, respectively. It was also observed that the presence of alkali metal ions influenced the adsorption capacity of the zeolites. The study inferred that the adsorbent was efficient and promising for multiple adsorption–desorption cycles without much deterioration of the capture capacity.

In the present work, adsorbents were prepared from rice husk in order to capture CO2 from a flue gas stream. Various pretreatment processes such as desilicalization, chemical activation, and K2CO3 impregnation were followed to prepare the adsorbents. The physico-chemical characterization of the adsorbents was performed in detail in an elaborated way. A fixed-bed reactor was used to measure the CO2 capture capacity of the in-house developed adsorbents. The effect of various process parameters such as adsorption temperature, moisture content, and loading of active component on CO2 adsorption capacity was studied, and results were compared with a commercially available activated carbon. The maximum adsorption capacity observed for 20K-ARH adsorbent was as high as 67 g of CO2/kg sorbent. The effect of water on CO2 adsorption was critically examined, and formation of KHCO3 was observed in the presence of water during the adsorption process. The optimum operating conditions for the maximum removal of CO2 from a simulated flue gas include a temperature range of 30–40 °C, relative humidity range of 80–90%, and K2CO3 loading of about 20 wt %. It was observed that around 94% of the adsorbed CO2 can be desorbed at 180 °C, and the adsorbent can be reused for multiple cycles without compromising the capture capacity significantly.

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In this study, zeolite-based sorbents were prepared and examined for CO 2 adsorption from a simulated flue gas mixture using a fixed-bed flow reactor. Various amines such as monoethanolamine, ethylenediamine, diethylenetriamine and triethylenetetramine (TETA) were impregnated on support materials to prepare the adsorbents. Also, the effects of various parameters on CO 2 adsorption capacity have been examined in this work. Further, an effort has been made to characterize various physico-chemical properties like surface area, pore volume, chemical composition, etc. of the in-house developed sorbents. Observation showed that the CO 2 adsorption capacity enhanced with amine loading up to a certain concentration. The maximum carbon capture capacity of the 30-TETA-ZSM-5 sorbent is around 53 g of CO 2 /kg of adsorbent. The thermochemical stability of the adsorbents has been tested by reusing the same material for multiple adsorption-desorption cycles, and no significant change in CO 2 adsorption capacities was observed.