Simultaneous stabilization of arsenic and antimony co-contaminated mining soil by Fe(Ⅱ) activated-Fenton sludge: Behavior and mechanisms
Yuliang Zhang, Zongwu Hou, Pingfeng Fu, Xiaofei Wang, Tianli Xue, Yuqi Chen
Abstract
Fenton sludge (FS) with high iron contents that discharged from the Fenton process was rarely studied for soil remediation . Herein, a novel Fe(Ⅱ) activated-Fenton sludge (FS–FeSO 4 ) was proposed to stabilize arsenic (As) and antimony (Sb) co-contaminated soil meanwhile disposing FS. Multiple characteristic analyses revealed that the porous structures and rich functional groups of FS-FeSO 4 involved in As and Sb adsorption. Meanwhile, Fe (hydro)oxides played a key role in As and Sb stabilization. Under the optimal application parameters (stabilizers dosage: 5%, incubation time : 60 days), the available As and Sb content decreased by 88.6% and 83.3%, respectively, and the leachability of As and Sb was reduced by 100% and 72.6% for FS-FeSO 4 stabilized soil. Moreover, the mobile As and Sb fractions (F1 and F2) were transformed into the most stable fraction (F5). The adsorption of As and Sb on FS-FeSO 4 was well fitted by pseudo-second-order kinetic and Langmuir models, while FS-FeSO 4 exhibited a better affinity for As than Sb under competition conditions. Poorly crystalline α-FeOOH and amorphous Fe (hydro)oxides provided sufficient active sites for As and Sb, and the generation of Fe–As/Sb and Ca–Sb chemical bonds promoted the stability of As and Sb. This study demonstrated that FS-FeSO 4 was a potentially effective stabilizer for As and Sb co-contaminated soil remediation .