化学
环境化学
连二亚硫酸钠
环境修复
土壤水分
溶解有机碳
铁质
溶解
连二亚硫酸钠
金属
硫酸盐
吸附
铵
总有机碳
污染
无机化学
环境科学
酶
生物化学
有机化学
生物
土壤科学
生态学
物理化学
作者
Shui‐Wen Chang Chien,Hsiou-Hsuan Wang,Yueming Chen,Ming-Kuang Wang,Cheng‐Chung Liu
标识
DOI:10.1016/j.jhazmat.2020.123549
摘要
General acid washing is commonly used to treat heavy metal-contaminated soils, but it is sometimes difficult to achieve remediation aims in severely polluted soils. If we expose the surfaces of Fe oxide minerals to reductive dissolution during washing treatment, more of the metals initially adsorbed to these surfaces will be liberated, which may encourage the removal of heavy metals. Initially, the metal extraction capabilities of nine chemical reductants were compared in ten soil samples polluted by Cr, Cu, Zn, and Ni. Sodium dithionite (Na2S2O4) and ferrous sulfate (FeSO4) were screened for subsequent intensive research. In summary, the Na2S2O4 solutions had higher Cr, Cu, and Zn removal rates than either the FeSO4 or acid solution. Application of dissolved organic carbon (DOC) further increased the removal of heavy metals by complexation. About 15%, 86%, 32%, and 52% of the Cr, Cu, Zn, and Ni, respectively, were removed from the representative soil (M-2) by two-stage washing using 0.2 M Na2S2O4 coupled with 1,500 mg L−1 DOC solution at pH 2.0. Meanwhile, most soil fertility was preserved: ammonium nitrogen was increased 3.9 times; the increase in exchangeable potassium was 33%; and the reduction in available P was only 10%.
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