苹果酸型端羧基超支化聚酯对矿区重金属污染土壤的淋洗效果

Effects of malic acid carboxyl-terminated hyperbranched polyester washing agents for heavy metal removal from soil

以苹果酸为AB2型共聚单体,三羟甲基丙烷(TMP)为中心核,通过酯化反应,成功制备了苹果酸型端羧基超支化聚酯(HBP-COOH),通过1HNMR和FT-IR对其结构进行了表征,并采用恒温振荡淋洗法,系统研究了HBP-COOH在不同使用浓度、pH值、淋洗时间及液固比条件下对矿区重金属污染土壤中Zn、Cd和Cu的淋洗效果。结果表明,相比于苹果酸而言,HBP-COOH对矿区土壤中Zn、Cd和Cu具有更好的淋洗效果,而且,HBP-COOH在质量浓度为1.5%(质量分数),液固比为25∶1,淋洗时间t=100min及溶液pH值=4时,HBP-COOH对Cu和Zn的去除率达到84.9%和93.8%;HBP-COOH在质量浓度为1.5%(质量分数),液固比为25∶1,淋洗时间t=140min及溶液pH值=3.0时,对Cd的淋洗效果最佳,达到95.2%。且经HBP-COOH淋洗后,矿区土壤的理化性质基本维持不变。

The malic acid carboxyl-terminated hyperbranched polyester (HBP-COOH) was successfully prepared by esterification with trimethylolpropane as core and malic acid as AB 2 monomer.Its structure was characterized by FTIR and 1 H NMR.And the HBP-COOH was applied to remove heavy metal from soil.The effects of HBP-COOH on removal of Zn,Cd and Cu from soil were investigated by batch experiments.The results showed that compared with malic acid,HBP-COOH had better leaching effect on Zn,Cd and Cu from the soil of mining area.Moreover,for HBP-COOH leaching agents,the removal efficiencies of Cu and Zn reached 84.9% and 93.8% at pH=4,liquid-solid ratio=25∶1,t =100 min and the concentration of 1.5wt%,respectively,and the maximum removal efficiency of Cd was 95.2% at pH=3,liquid-solid ratio=25∶1,t =140 min and the concentration of 1.5wt%.And the HBP-COOH had less effects on basic physical-chemical properties of soil.