聚酰胺复合纳滤膜去除水中PFOS的研究

利用聚酰胺复合纳滤膜去除水中的PFOS，在0.6MPa操作压力条件下过滤12h，研究PFOS浓度、离子种类、总离子强度以及海藻酸对PFOS截留效果的影响.结果表明，随着PFOS浓度增大其截留率也随之升高；溶液总离子强度越大，PFOS截留率越高，当过滤进行到12h时，溶液总离子强度为150mmol/L时，PFOS的截留率比溶液总离子强度为10mmol/L时仍高2.1%；溶液中加入1mmol/L Ca²⁺时PFOS的截留效果优于加入1mmol/L Na⁺时的效果；并且随着二价离子浓度的增加，截留率上升，过滤结束时，Ca²⁺浓度为3mmol/L的条件下PFOS的截留率约为97.5%，高于1mmol/L Ca²⁺存在时PFOS的截留率（95%）；海藻酸存在时PFOS的截留率显著增高，尤其在1mmol/L钙离子存在条件下，过滤12h后PFOS的截留率仍可达到95%以上，但海藻酸会导致膜污染的发生从而引起膜通量下降.

Removal of PFOS in water by polyamide composite nanofiltration membrane

In this study, PFOS removal was investigated by using polyamide nanofiltration membrane. The effects of PFOS concentration, ionic types, total ionic strength, and alginate on PFOS rejection were investigated through 12h filtration experiments with operation pressure of 0.6MPa. The results showed that PFOS rejection increased with the increase of PFOS concentration as well as total ionic strength. After 12h filtration, PFOS rejection under the total ionic strength of 150mmol/L was 2.1% higher than that of 10mmol/L.Specifically, compared with that of 1mmol/L Na⁺ existing condition, PFOS rejection was larger when 1mmol/L Ca²⁺ existed. Moreover, PFOS rejection increased with the enlargement of divalent ionic strength. After 12h filtration, PFOS rejection was about 97.5% when 3mmol/L Ca²⁺ existed in feed solution, which was greater than 95% of 1mmol/L Ca²⁺ condition.Besides, the existence of alginate resulted in the significant improvement of PFOS rejection, and the removal rate could still reach up to 95% after 12h filtration when calcium ions coexisted. However, alginate could also cause membrane fouling which led to the decline of membrane flux.