Mitigation of arsenic accumulation in arugula (Eruca sativa Mill.) using Fe/Al/Zn impregnated biochar composites

Arsenic (As) contamination of aquatic and soil environments is a global concern, highlighting the importance of As removal via high-efficiency and low-cost removal technologies. In the present study, novel trimetallic biochar was developed through pyrolyzing corn straw impregnated with inexpensive metal Fe/Al/Zn (hydr)oxides. The results of SEM, FTIR, and XRD verified the formation of metal oxyhydroxides on the surface of the modified biochars, and the modification increased the specific surface area (SSA), total pore volume (TPV), and surface charge of the Fe/Al/Zn (hydr)oxides modified biochar (FAZ-CB). Compared with the original biochar, higher sorption rates and capacities was observed for the FAZ-CB. The maximum As (V) adsorption capacities of FAZ-CB reached 82.9 mg g^-1. A pot experiment showed that application of FAZ-CB decreased bioavailable As fractions in the red soil significantly reduced the uptake of As by arugula in edible part and root (42.6 and 56.8%, respectively). The present study demonstrated the superiority of FAZ-CB in the As(V) immobilization in red soil, suggesting that it is a promising candidate for practical application for As immobilization. Therefore, FAZ-CB can be used as a promising functionalized biochar to remediate As contaminated red soil.