Modification of waste sugarcane bagasse fly ash for CO2 capture application

Abstract

CO2 capture is a promising approach to aid in the mitigation of the global environmental crisis caused by greenhouse gas emissions. The efficiency of adsorbents is critical to the success of this approach. Sugarcane bagasse fly ash (SBA) was used in this study as a support to increase the CO2 adsorption capacity of CaO. The physical and chemical characteristics of SBA treated with various reagents (HCl, H3PO4, CH3COOH, NaOH, NH3, and H2O2) were investigated. The CaO was then loaded at 10–50 wt% on the support surface, and the modified adsorbent was tested for its potential to adsorb CO2. According to the results of the experiments, the acidic reagent increased the surface area of SBA, whereas the base reagents provided SBA with a higher pore volume and a larger pore size. The different surface characteristics of the modified SBA had a direct impact on its CO2 adsorption capacity. The adsorbent with NaOH-pretreated SBA and 50% CaO loading had the highest CO2 adsorption capacity, which was 27% higher than that of unsupported CaO due to the decent distribution of CaO found on the NaOH-treated SBA surface. For a better understanding, a graphical model was finally proposed to describe the aforementioned changes in surface characteristics and adhesion of CaO on the SBA support. These findings show that SBA, a valueless bagasse-incinerating waste material, can be used as a support to increase the CO2 adsorption capacity of adsorbents, transforming it into a more valuable and environmentally sustainable material. Graphical abstract: [Figure not available: see fulltext.]