In Situ Chemical Stabilization of Arsenic-contaminated Soils Using Ferrous Sulfate

In this paper, a probe into the stabilization effects of ferrous sulfate (FeSO4) came from two aspects-stabilization efficiency and leachate content. Fe/As molar ratio, arsenic pollution intensity, soil pH, reacted time interval, competitive ions, such as sulfate(SO42-), phosphate(PO43-) and zinc ion(Zn2+), were studied in order to discuss their effects on the stabilization of arsenic. Results show that, to all different levels of arsenic contaminated soils, when Fe/As molar ratio reaches 6, arsenic stabilization efficiency exceeds 90%, and arsenic concentration in leachate could also reduce to less than 5 mg/L; in the soil pH range from 8.10 to 8.57, ferrous sulfate has obtained the preferable results, and pH= 8.23 is the optimum value; because of existing of competitive actions, the exogenous adding of SO42-. PO43-and Zn2+ could lead to much poorer performance for FeSO4.