[Inhibition and Remediation of Methylmercury Contaminated Soil by Use of Modified Montmorillonite].

ABSTRACT

Montmorillonite was modified by 3-mercaptopyl trimethoxysilane and chitosan. The modified montmorillonite was characterized by XRD technology. The effects of thiol montmorillonite and chitosan montmorillonite on the inhibition and remediation of methylmercury contaminated soil under different water conditions were studied using laboratory simulation. XRD results showed that both thiol and chitosan were successfully loaded on the montmorillonite. The results of simulation tests showed that the addition of the remediation material to soil contaminated with methylmercury produced a better remediation effect. Compared with the blank control, the content of methylmercury in the soil was reduced by 82.10% (thiol montmorillonite) and 45.20% (chitosan montmorillonite), respectively, in the flooded condition. Under dry/wet alternation, the content of methyl mercury in soil decreased by 66.70% (thiol montmorillonite) and 49.79% (chitosan montmorillonite), respectively. Under drought conditions, the content of methylmercury in soil decreased by 44.66% (thiol montmorillonite), and the concentration of methylmercury in soil decreased by 54.37% after adding chitosan montmorillonite for 4 weeks. Compared with single modified montmorillonite, the repair effect of combined modified montmorillonite and lime treatment was not improved significantly.