Qualitative and quantitative correlation of physicochemical characteristics and lead sorption behaviors of crop residue-derived chars

Abstract This study investigated the key physicochemical characteristics of char that control its ability to absorb Pb 2+ . Three type of crop residue-derived chars and their ball milled powder were characterized using multiple approaches. The Pb 2+ sorption mechanisms of biochar were caused mainly by coprecipitation reactions, which were governed by ionic minerals on chars instead of mineral crystallization (e.g., SiO 2 and Al 2 O 3 ), while coprecipitation reactions and π electronic interaction were the dominant mechanisms of activated carbon. Pearson analysis showed that adsorption quantity (Q) highly correlated with the cation exchange capacity (CEC) (P  2  ＞ 0.8)/OFGs (R 2  ＞ 0.7) were established. CEC and OFGs of chars are the key factors controlled Pb 2+ sorption. These results may promote the development of low-cost, engineered biochar with superior sorption qualities for environmental remediation.