Synthesis and application of two types of amine sorbents impregnated on silica from coal fly ash for CO2 capture
Vanessa O. Viola, Thiago Fernandes de Aquino, Sabrina Teixeira Estevam, Beatriz Bonetti, Humberto Gracher Riella, Cíntia Soares, Natan Padoin
Abstract
CO2 capture by adsorption using porous materials synthesized from industrial waste is an economical and environmental alternative aimed at technologies currently being developed in different areas of engineering. This work synthesized silica from coal fly ash by the fusion method followed by acid leaching, with a final surface area greater than 200 m2/g and a pore volume greater than 0.16 cm³/g, without the use of any template agent, forming a better quality and more efficient material when compared to other adsorbents synthesized from wastes. The obtained support was wet impregnated with PEI and TEPA amines in different mass percentages and its performance showed a CO2 adsorption capacity up to three times higher when compared to other results presented in the literature. The best adsorption capacity was found at 85 °C, for adsorbents impregnated with 50 % PEI (1.304 mmol/g) and 60 % TEPA (2.086 mmol/g), confirming the largest layer of TEPA in relation to CO2. The same adsorbents were used in the analysis of 20 adsorption/desorption cycles and the final capacities were 1.128 mmol/g and 1.069 mmol/g, respectively, confirming the better thermal stability of PEI. After 20 cycles, both adsorbents showed the possibility of regeneration and the possibility of application in TSA processes. These results can be improved in the presence of humidity and make the application of the developed adsorbent even more promising, demonstrating the importance of this study.