CO2 capture using biochar derived from conditioned sludge via pyrolysis

To reduce pollution and simultaneously mitigate carbon emission. Biochar samples were prepared via the py-rolysis of sludge after conditioning with K2FeO4 and cationic polyacrylamide (CPAM) or chitosan (CTS), and their CO2 capture performance was compared. The optimal preparation conditions were 600 degrees C and 80 mg/g dry solid (DS) for K2FeO4, 20 mg/L for CPAM, and 1 mg/g DS for CTS. The results showed that the CO2 capture capacity of the biochar with K2FeO4 (K2FeO4-B) increased from 75.69 mg/g to 81.68 mg/g compared to RSB, the CO2 capture capacity of the biochar with PF + CPAM (K2FeO4-CPAM-B) was 94.81 mg/g, and the CO2 capture capacity of the biochar with PF + CTS (K2FeO4-CTS-B) was 86.56 mg/g. The CO2 capture capacity of the biochar (K2FeO4-CTS-B) was 86.56 mg/g. The main reason for this improved capacity is that the addition of K2FeO4 and CPAM enhanced chemical properties of the biochar surface (carbon content, N-H content, etc.). Additionally, the biochar conditioned with K2FeO4 and CPAM demonstrated better cyclic adsorption performance and economic efficiency than the other samples. It has the prospect of engineering application. This study provides a reference for the selection of conditioning agents for wastewater treatment plants and a new solution for sludge disposal.