3种环保型淋洗剂对重金属污染土壤的淋洗效果

采用振荡淋洗法研究衣康酸(IA)、丙烯酸-2-丙烯酰胺-2-甲基丙磺酸共聚物(AA/AMPS)和衣康酸-丙烯酸共聚物(IA-AA)在不同因素影响下对污染土壤Cd、Pb和Zn的淋洗效率。结果表明：3种淋洗剂对土壤Cd、Pb和Zn的去除率随其浓度增加而快速上升，随pH增加呈迅速下降和先升高后降低2种趋势，随淋洗时间总体呈上升趋势；3种淋洗剂在浓度为0.15 mol·L-1且pH为3时，对Cd和Zn去除率最高（39.34%~65.65%）；在相同浓度和pH为5条件下对Pb的去除率最高（22.05%~50.62%）。其中IA-AA对Cd、Pb和Zn的去除率分别可达65.65%、50.62%和44.92%。它们去除的主要重金属组分为酸溶态、可还原态和部分可氧化态，且经IA和IA-AA淋洗的土壤养分损失相对较小。因此，IA-AA是修复Cd、Pb和Zn复合污染土壤有工程应用前景的淋洗剂。

Effects of different environmentally friendly washing agents on removal of soil heavy metals

The effects of three eco-friendly materials including itaconic acid (IA), acrylic acid-2-acrylamido-2-methylpropane sulfonic acid copolymer (AA/AMPS), and itaconic-acrylic acid copolymer (IA-AA) on the removal of Cd, Pb and Zn from contaminated soil were investigated by batch experiments. Results showed that the soil Cd, Pb and Zn removal efficiencies increased dramatically with increasing the concentrations of washing agents, while decreased sharply or augmented at the beginning and then declined quickly with the increase of pH levels. However, they kept increasing over contact time. For three leaching agents, the removal efficiencies of Cd and Zn reached from 39.34 to 65.65% at pH 3 and the concentration of 0.15 mol·L-1, and the removal efficiency of Pb was from 22.05 to 50.62% at pH 5. Among of them, IA-AA had an excellent ability for Cd (65.65%), Pb (50.62%) and Zn (44.92%) removal. The exchangeable, reducible and part of oxidizable fractions of Cd, Pb and Zn decreased markedly after washing. IA and IA-AA had less effects on soil nutrients compared with AA/AMPS. Therefore, IA-AA could be as a potential material to remediate heavy metal contaminated soil.