钙基固化剂对钒矿污染土壤固化效果的研究

针对国内外对钒矿污染土壤修复研究少的现状,选择氧化钙、氯化钙、羟基磷灰石三种钙基固化剂对钒矿污染土壤进行固化效果研究。结果表明:在中性环境下,三种钙基固化剂分别在0.5%、1%、2%添加量时,对钒(V)的固化率由高到低依次为氧化钙氯化钙羟基磷灰石,对铬(Cr)的固化效果为氧化钙优于氯化钙和羟基磷灰石;除添加2%氯化钙外,其他固化剂的不同添加量均降低了V的伴生重金属Cd、Cu、Pb、Zn的浸出量;在添加量2%、固化3h时,氧化钙对V和Cr的固化率分别达到99.0%和38.6%;氧化钙固化污染土壤后,V的残渣态比例为22.9%,比固化前提高了76.2%。

Immobilizing effects of calcium-based agents on soil contaminated by vanadium ore

There are not many investigations available regarding the remediation of vanadium(V)-contaminated soil. Here three calcium-based immobilizing agents, i.e. calcium oxide, calcium chloride, and hydroxyl-apatite, were employed to investigate their immobilizing effects on V-contaminated soil. Results showed that the efficiency of different agents for immobilizing V exhibited in order of calcium oxide> calcium chloride> hydroxyl-apatite, at a rate of 0.5%, 1%, and 2%, respectively, under neutral-pH conditions. Calcium oxide showed a better immobilizing efficiency for Cr than calcium chloride and hydroxyl-apatite did. In acidic conditions, calcium oxide was still better in immobilizing V than calcium chloride and hydroxyapatite were. Calcium oxide and calcium chloride increased Cr immobilization, but hydroxyapatite promoted Cr leaching under acidic conditions. After 14 d of treatment, the immobilizing efficiencies did not change over time. The releases of other V-accompanied heavy metals, i.e. Cd, Cu, Pb, and Zn, were reduced by all three agents at all rates, expect calcium chloride at 2%. Applying calcium oxide at 2% immobilized V and Cr by 99.0% and 38.6%, respectively, after a 3-h. In calcium oxide treatment, soil residual V was 22.9%, which increased by 76.2% as compared to the untreated soil.