[Remediation Effect of Iron-manganese Composite-modified Biochar from Different Biomasses on Cd-contaminated Alkaline...

To investigate the remediation effect of iron-manganese-modified biochar from different biomasses （FM-BC） on Cd-contaminated alkaline soil, FM-BC was prepared using branches of Robinia pseudoacacia, durian shells, and corn stalks. The characteristics of FM-BC, the adsorption of Cd（Ⅱ） in water, and the available, fraction of Cd in alkaline soil were studied using bath adsorption and soil culture experiments. The results showed that the specific surface area, total pore volume, and oxygen content of FM-BC were significantly improved. The maximum Cd（Ⅱ） adsorption capacity of FM-BC in water was 50.71-98.09 mg·g^-1, which was 1.61-4.27 times higher than that of BC. After adding 0.5%-3% FM-BC, the content of DTPA-Cd was reduced by 11.77%-37.73%, and the carbonate-bound fraction and iron-manganese oxide-bound fraction of Cd were increased by 8.61%-13.72% and 6.74%-35.05%, respectively. The remediation of Cd-contaminated alkaline soil by FM-DBC was significantly better than that of FM-RBC and FM-YBC. The characterization results showed that CO₃^2-, C-O, Fe-O, and Mn-O in FM-DBC were the main adsorption sites, which immobilized Cd through precipitation and complexation. The above results indicated that FM-DBC has application potential for Cd-contaminated alkaline soil remediation.