Abstract:
Objective The effects of four stabilization materials (alkaline boron sludge, acidic boron sludge, kaolin and iron modified biochar) on the simultaneous stabilization and remediation of cadmium-arsenic (Cd-As) combined contaminated soil were investigated.
Method Alkaline boron sludge, acidic boron sludge, kaolin and Fe-modified biochar were added to the soil contaminated by Cd and As at the ratio of 0.5%, 1%, 2% and 5%, respectively, for constant temperature and humidity culture. The effects of different stabilization materials on soil pH value and available contents of Cd and As were studied.
Result Except alkaline boron mud, the other three materials all reduced the soil pH value. The 5% iron modified biochar significantly decreased the soil pH value, by 3.12 units after 21 days treatment. The 5% Fe-modified biochar has the best stabilization effect on As, the stabilization efficiency was 57.17%, followed by 5% kaolin and 5% acidic boron sludge, the stabilization efficiencies were 40.40% and 33.37%. The 5% Fe-modified biochar also had the best stabilization effect on Cd, with the stabilization efficiency of 35.03%, followed by the 5% alkaline boron sludge with 28.20%.
Conclusion Considering the effects of simultaneous stabilization of Cd and As in soil, the effects of Fe-modified biochar were better than the other three stabilized materials.