Remediation of Cd and Zn contaminated soil by zero valent iron (Fe0): A field trial

Remediation of contaminated soil is a long-term challenge faced by human beings. The in-situ remediation was carried out using zero valent iron (Fe 0 ) with the rotation pattern of soybean-rape the near a smelter influenced by atmospheric subsidence. The results showed that the total contents of Cd and Zn in rhizosphere soils with Fe 0 treatment were lower than that in the control. The biomass of soybean and rape increased by 55.4 ∼ 64.9% and 6.2 ∼ 42.8%, respectively with the addition of Fe 0 . And Fe 0 decreased the availability of Cd and Zn and the accumulation of Cd and Zn in plant roots. The Cd and Zn contents of the iron-rich substances separated from soil were much high, reaching 155.8 mg/kg and 29525 mg/kg, respectively and the total Cd and Zn in the remaining soil decreased by 28.5% and 44.6%, respectively. XRD and XPS analysis of the separated substance implied that the new production of iron oxides ( γ -FeOOH and γ -Fe 2 O). The existence of CdO and CdS were obversed and the main forms of Zn were ZnS, ZnO and ZnCO 3 through the immobilization of iron oxides. This work suggested the feasibility of Fe 0 in the contaminated soil. Using retrievable materials from soil to remove permanently pollutants should be considered in the future remediation practice. • The in-situ remediation effect of zero valent iron (Fe 0 ) on Cd and Zn was explored. • Fe 0 decreased the contents of Cd and Zn in crop roots. • The iron-rich substance had high contents of Cd and Zn. • The iron-rich substance was retrieved successfully from soil.