Remediation of polymetallic contaminated soil with modified chitosan materials
With the rapid development of industry,especially the rapid expansion of mining and smelting industries,serious soil heavy metal pollution has been caused.In order to realize the simultaneous remediation of soil contaminated by heavy metals,the farmland soil around a lead-zinc mine in southern Sichuan was taken as the research target.Through soil cultivation experiments,the effects of different ratios of chitosan(CS)and four modified chitosan materials on the basic physicochemical properties of polluted soil,the DTPA effective state and distribution form of heavy metals(Cu,Pb,Zn,Cd)in soil,and the migration characteristics of heavy metals were investigated to select the best material for the target heavy metal passivation.The study found that using different ratios of CS and modified chitosan materials resulted in an increase in soil pH,organic matter(OM)and cation exchange capacity(CEC)in farmland soil contaminated with Cu,Pb,Zn and Cd.The increase in these parameters showed an upward trend with increasing addition.The application of a certain proportion of CS increased the content of available Cu and Pb,while the four modified chitosan materials reduced the content of available Cu,Pb,Zn and Cd,reducing the bioavailability and mobility of heavy metal pollution.Meanwhile,the addition of all five materials could effectively promote the transformation of Cu,Pb,Zn and Cd from the weak acid extraction state to the stable residue state in the soil,and the best passivation effect was achieved when ECS-B was added to the soil with a mass ratio of 2.5％.This study indicated that ECS-B material was effective in passivating Cu,Pb,Zn and Cd contaminated soil,and had potential application for remediation in the field of heavy metal contaminated soil.
万方数据
维普
