Leaching release behavior of soil Cd(Ⅱ)under the magnetic nano-S-ZnFe2O4
A soil column leaching test was carried out to study the leaching release behavior of Cd(Ⅱ)in cadmium-contaminated soil under the S-ZnFe2O4 magnetic nanomaterials.The results showed that S-ZnFe2O4 had a superior passivation effect on soil Cd.Cd(Ⅱ)leaching release from contaminated soil with Cd content of 5.69 mg·kg-1 was reduced by 96.02％compared with that of the blank group,when the leaching solution pH was 5,and the dosage of S-ZnFe2O4 was 1.5％(wt),and the average effective recovery with magnetic separation recovery of S-ZnFe2O4 could reach 77.94％.The adsorption of soil Cd(Ⅱ)by S-ZnFe2O4 was mainly through surface complexation,ion exchange,and electrostatic attraction,a large amount of cadmium with high activity in the soil was transformed into Fe-Mn oxides-bound forms and organic matter-bound forms,and the proportion of cadmium in exchangeable forms and carbonate-bound forms decreased by 34.13％and 22.65％,respectively.The coexistence of Pb(Ⅱ),Zn(Ⅱ),Cr(Ⅲ),and Ni(Ⅱ)ions promoted the immobilization of Cd(Ⅱ)of the material,while Cu(Ⅱ)increased the leaching of Cd(Ⅱ)by 12.92％.The as-prepared S-ZnFe2O4 magnetic nanomaterials have the advantages of being highly adsorptive,recoverable by magnetic separation and simple preparation method,which can greatly reduce soil Cd(Ⅱ)activity and lower the risk of groundwater contamination by soil Cd release.This study provides valuable insights for the remediation of cadmium-contaminated soil.
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