几种土壤及黏土矿物对多氯联苯吸附特性的研究

采用批量平衡试验,研究了不同土壤及长黏土矿物对多氯联苯吸附特性。结果表明:多氯联苯浓度范围为0.25~5.0mg L-1时,不同土壤及黏土矿物对多氯联苯的吸附均能用Freundlich方程很好地拟合,随着溶液中多氯联苯浓度的增加,土壤及黏土矿物对多氯联苯的吸附量增加;几种土壤对多氯联苯吸附量大小顺序为:红壤>黄褐土>砂姜黑土,土壤有机质、粘粒等对多氯联苯吸附起主要作用,土壤更易吸附高氯代PCB77;黏土矿物对多氯联苯吸附量大小顺序为:纳米蒙脱石>纳米SiO2>凹凸棒石,黏土矿物吸附多氯联苯能力的大小与黏土矿物的比表面积、粒径、层状结构等有关;多氯联苯本身分子的大小影响其在黏土矿物上的吸附;土壤中添加黏土矿物可以提高对多氯联苯的吸附。

Adsorption Charcteristics of PCBs in Soils and Clay Minerals

Adsorption characteristics of PCBs in soils and clay minerals were studied using the batch equilibration technique.Results showed that the adsorption of PCBs conformed to the Freundlich equation when the concentrations of PCBs were from 0.25 mg L-1 to 5.0 mg L-1,and the adsorption of PCBs in soils and clay minerals increased with the increase of initial concentration.The adsorption capacity of soils for PCBs followed the order red soil > yellow brown soil > shajiang black soil.The contents of organic matter and clay in soil governed adsorption of PCBs,and the high chlorine of PCBs were easier to be absorbed by soils.The adsorption capacity of clay minerals for PCBs followed the order nanometer-sized montmorillonite > nanometer-sized SiO2 > attapulgite.The adsorption ability of clay minerals for PCBs related to the surface area,diameter and layered structure of clay minerals.The molecular size of PCBs also affected the adsorption.Adding clay minerals to soil could improve the adsorption ability.