甲醇对多氯联苯在低密度聚乙烯膜上解吸动力学的影响  

The effect of methanol on desorption of polychlorinated biphenyl in low density polyethylene

作　　者：冯伟昊 鲍恋君[1] 曾永平[1] 

机构地区：[1]中国科学院广州地球化学研究所,有机地球化学国家重点实验室,广州510640 [2]中国科学院大学,北京100049

出　　处：《环境化学》2014年第1期108-114,共7页Environmental Chemistry

基　　金：国家自然科学基金项目(41121063;21277144);广东省自然科学基金项目(S2012020011076)资助

摘　　要：通过分别用纯水和甲醇-水溶液作为预吸附液使单个多氯联苯(PCB-52、PCB-185和PCB-209)分配到低密度聚乙烯膜后,再在纯水中解吸(解吸时间2—110 d),运用交换速率常数和解吸百分比来确定甲醇对目标物解吸动力学的影响.实验结果显示,目标物在两种预吸附方法的交换速率常数没有显著性差异(PCB-52:P=0.96;PCB-185:P=0.19;PCB-209:P=0.46),但负值的交换速率常数暗示:本实验中可能不适合用其来评价甲醇对目标物解吸的影响.而PCB-52在采用纯水与甲醇-水溶液作为预吸附液时所得解吸百分比之间没有显著性差异(P=0.37),但PCB-185和PCB-209的解吸百分比均存在显著性差异(P<0.01),故甲醇可能影响PCB-185和PCB-209的解吸动力学.因此,在应用以低密度聚乙烯膜为吸附相的被动采样器,并以行为参考物校正法作为定量依据测定水体中疏水性有机物时,需谨慎使用以甲醇作为助溶剂的预吸附液将强疏水性的行为参考物分配至吸附相.Three polychlorinated biphenyl （PCB） congeners,i.e.,PCB-52,PCB-185 and PCB-209,were impregnated into low density polyethylene （LDPE） films in high purity water and methanol-water mixture,and then desorbed in high purity water from 2 to 110 d,respectively. The effect of methanol as co-solvent on the desorption kinetics of the target compounds in high purity water was determined by comparing the exchange rate coefficients （ke） and percentages of desorption for two preloaded methods.No significant differences were found between two preloaded methods for all target compounds （PCB-52： P=0.96,PCB-185： P=0.19,and PCB-209： P=0.46）,but the negative values for ke implied that ke was probably not suitable for assessing the effects of methanol on the desorption of the target compounds.On the other hand,significant differences were found between the percentages of desorption of PCB-185 and PCB-209 （P 〈 0.01） preloaded by two preloaded methods except for PCB-52 （P=0.37）.These results suggested that methanol as co-solvent may impact the desorption kinetics of PCB-185 and PCB-209.Therefore,it should be cautious in using methanol as a co-solvent for impregnating performance reference compounds with strong hydrophobicity into LDPE films in passive sampling of hydrophobic organic chemicals.

关 键 词：低密度聚乙烯膜 甲醇 疏水性有机物 解吸动力学 

分 类 号：TB383.2[一般工业技术—材料科学与工程]