吸附材料对钒矿污染土壤重金属的稳定化效果

选用壳聚糖和活性炭两种吸附材料,分别以不同的质量比添加到供试土壤中,固化后进行毒性浸出实验,研究吸附材料对土壤中钒(V)、铬(Cr)的稳定化效果,并通过表征吸附材料的红外光谱(FTIR)和X射线光电子能谱(XPS)探究吸附材料对V、Cr的稳定化机理.结果表明,壳聚糖对V、Cr均有较好的稳定化效果,活性炭对V的稳定化效果不稳定,对Cr的稳定化效果很好.吸附材料添加量的改变对稳定化效果影响不大.稳定化30d时,0.5%壳聚糖对V、Cr的稳定化率分别为74.04%、46.77%;0.5%活性炭对V、Cr的稳定化率分别为1.86%、87.75%.FTIR和XPS表征结果表明,壳聚糖中含活性强的氨基和羟基较多,活性炭中含氨基、羟基较少.因此壳聚糖和活性炭可作为土壤重金属的稳定剂,使钒矿污染土壤得到修复.

Stabilization of V contaminated soils with adsorption materials

Chitosan and activated carbon, with different quality ratio, was added into the tested soil, then toxicity leaching experiments were conducted to study the stabilizing effect of adsorption materials on V and Cr from the tested soil. Besides, FTIR (Fourier Transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy) were performed to explore the stabilization mechanism of the adsorption materials. Chitosan could significantly reduce the leaching concentration of V and Cr from the contaminated soil. The stabilizing effect of activated carbon on Cr was better than that on V from the tested soil, while the stabilizing effect was not affected significantly by the dosage of adsorption materials. The stabilization rate of V and Cr from the tested soil was 74.04% and 46.77%, respectively, by chitosan with the dosage of 0.5% after 30d stabilization; while 1.86% of V and 87.75% of Cr could be stabilized, respectively, when 0.5% of active carbon was used. FTIR and XPS results on the adsorption materials showed that there were numerous of amino and hydroxyl groups in the chitosan, while amino and oxygen-containing groups were limited in activated carbon. Thus, chitosan and activated carbon were promising stabilizers available to remediate the contaminated soil.