离子交换树脂对水中全氟羧酸的吸附去除

Removal of Perfluorocarboxylic Acids from Water by Anion Exchange Resins

分别在超纯水配水和饮用水源水中,考察了4种结构与性质不同的阴离子交换树脂对具有不同碳氟链长度的全氟羧酸的吸附特性。在pH和离子强度分别为7.2和0.002 mol/L的超纯水中,凝胶型聚苯乙烯强碱树脂B和大孔型聚苯乙烯强碱树脂C对全氟羧酸的吸附去除效果最好,其中树脂B对初始浓度为500 ng/L的全氟戊酸、全氟己酸、全氟庚酸和全氟辛酸的去除率均达到80%以上,对亲水性最强的全氟己酸去除率达到75%以上。碳氟链长度对离子交换树脂去除水中全氟羧酸的效果影响较大,碳氟链长度越短,全氟羧酸的亲水性越强,离子树脂对其的去除率越低。根据实验结果,水中一定量的NOM能够显著促进离子交换树脂对全氟羧酸的吸附去除,在超纯水的实验中,树脂A对亲水性较强的全氟己酸去除率仅为18%,在含有一定浓度的NOM的饮用水源水的实验中,树脂A对全氟己酸的去除率升高至70%。

Perfluorocarboxylic acids （PFCAs） with different C-F chain-length were removed by four ion exchange resins with ultrapure water and drinking water respectively. Among the resins applied in the experiments, the strong base resin B and C exhibited the most efficient removal on PFCAs from ultrapure water. When the pH and ion strength were 7.2 and 0.002 mol/L, more than 80% of the initial 500 ng/Lperfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid and perfluorooctanoic acid were removed from ultrapure water, thus 75% ofperfluorobutanoic acid, the most hydrophilic compound in the experiment, was removed. Due to the less hydrophilicity, removal of PFCAs with longer C-F chain length was higher than PFCAs with shorter chain length. The removal of PFCAs could be enhanced by NOM in water. Accouding to the experiments results, resin A removed 18% of initial perfluorobutanoic acid from the ultra pure water reaction system, while 70% of initial perfluorobutanoic acid was removed from drink water by resin A.