木糖醇型端羧基超支化聚酯/L35复合淋洗剂对矿区污染土壤中重金属的淋洗效果

Effects of xylitol hyperbranched polyester/L35 compound eluent for heavy metal removal from contaminated soil in mining area

以木糖醇为中心核,柠檬酸为共聚单体,采用熔融聚合成功制备了木糖醇型端羧基超支化聚酯(HBP-COOH),并采用振荡淋洗法研究了在不同条件下所制备的HBP-COOH及其与L35复配后对尾矿库区污染土壤Cd、Pb和Zn的淋洗效果。实验结果显示:HBP-COOH的使用浓度及淋洗时间与淋洗效果呈现出正相关性。且在浓度c=2.5%、t=120 min且pH=4时,HBP-COOH对Pb和Zn的去除率最高;在浓度c=2.5%、t=150 min和pH=3时对Cd的去除率最高。而且HBP-COOH对Cd的淋洗效果比对Pb和Zn的淋洗效果更好。另外,相对于HBP-COOH而言,HBP-COOH/L35复配后有更加优异的淋洗效果,且HBP-COOH/L35复合淋洗剂对污染土壤具有良好的生态效应。研究结果表明,HBP-COOH/L35复合淋洗剂可以用于尾矿库区重金属污染控制的绿色淋洗剂。

With xylitol as the core and citric acid as the AB3 comonomer, xylitol carboxyl-terminated hyperbranched polyester(HBP-COOH) was successfully prepared by melt polymerization method, and the leaching effect of heavy metals by using HBP-COOH and its combination with L35(HBP-COOH/L35) as eluant on soil of mine tailings under different factors was studied by the oscillatory leaching method. The results showed that: when using HBP-COOH as eluant, the removal rates of Cd, Pb and Zn, increased with the increase of the concentration of HBP-COOH and the extension of the leaching time;at the concentration of 2.5%, t=120 min and pH=4, the removal rates of Pb and Zn were the highest;at the same concentration, t=150 min and pH=3, the removal rate of Cd was the highest, and HBP-COOH had the best removal efficiency on Cd. In addition, compared with HBP-COOH, HBP-COOH/L35 had a better removal efficiency on heavy metals, and the basic physical and chemical properties and microbial changes of soil of mine tailings were relatively small. Making this comprehensive consideration, HBP-COOH/L35 compound eluent can be used as environmentally friendly eluent for Cd, Pb and Zn in polluted soil of mine tailings.