Simultaneous stabilization of arsenic and antimony co-contaminated mining soil by Fe(Ⅱ) activated-Fenton sludge: Behavior and mechanisms

Environ Pollut. 2023 Nov 15:337:122538. doi: 10.1016/j.envpol.2023.122538. Epub 2023 Sep 12.

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-FeSO4) 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-FeSO4 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-FeSO4 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-FeSO4 was well fitted by pseudo-second-order kinetic and Langmuir models, while FS-FeSO4 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-FeSO4 was a potentially effective stabilizer for As and Sb co-contaminated soil remediation.

Keywords: Adsorption; As and Sb co-contaminated soil; Fe (hydro)oxides; Fenton sludge; Stabilization.

MeSH terms

  • Antimony / analysis
  • Arsenic* / analysis
  • Ferrous Compounds / chemistry
  • Oxides / chemistry
  • Sewage
  • Soil / chemistry
  • Soil Pollutants* / analysis

Substances

  • Arsenic
  • Antimony
  • Sewage
  • Soil Pollutants
  • Soil
  • Oxides
  • Ferrous Compounds