改性聚氯乙烯膜对酸性染料的抗污染性能和清洗效果研究

ANTIFOULING PROPERTY AND CLEANING EFFECT OF MODIFIED PVC MEMBRANE ON DIFFERENT ACID DYES

采用ATRP法将烯丙基聚乙二醇（APEG）单体接枝到聚氯乙烯（PVC）分子链上,NIPS法制备PVC及改性膜,泡点-流速法测定膜的孔径分布,水接触角表征膜的亲水性,同时研究成膜对酸性媒介红S-80、酸性媒介漂蓝B、酸性媒介蓝A3R染料的过滤性能,并分别用水、酸、碱对污染膜进行清洗,以膜通量的恢复率表征清洗效果;高效液相色谱法测定PVC及改性膜材料对染料的吸附性能。结果表明,膜的孔径分布在0.14-0.30μm,改性后PVC膜的初始水接触角从80.6°降至63.4°;改性PVC膜材料对3种染料的吸附作用明显减小,而改性PVC膜仅对酸性媒介漂蓝B的抗污染性有显著提高;实验还显示浓差极化作用是影响PVC及改性PVC膜过滤通量的主要因素,浓差极化阻力占到总阻力的50%-70%;水对改性PVC膜具有良好的清洗效果,膜通量恢复率达到80%。

APEG macromonomer was grafted to PVC molecular chain via ATRP method. NIPS method was applied to prepare the unmodified and modified PVC membrane. The membrane pore size distribution was measured by Bubble point-mean flow method and the hydrophilicity of membrane was characterized by water contact angle measurement. The acid dye solution of Acid Mordant Red S-80, Acid Mordant Light Blue B and Acid Mordant Blue A3 R were filtrated with PVC membrane to characterize the membrane fouling property. The polluted membrane was cleaned with water, acid and alkali solution, respectively, and the cleaning effect was determined by the recovery rate of membrane flux. HPLC method was used to measure the adsorption performance of unmodified and modified PVC membrane materials on dyes. The results showed that the pore size distribution of PVC membrane was in range from 0.14~0.30 μm. The initial water contact angle of unmodified PVC membrane was 80.6°and modified PVC membrane decreased to 63.4°.The adsorption of modified PVC membrane material on the three kinds of dyes decreased obviously, but the anti-pollution performance of modified PVC membrane increased significantly only on Acid Mordant Light Blue B. The experiment results showed that the concentration polarization was the main factor that affected the filtration flux of unmodified and modified PVC membrane. The concentration polarization resistance accounted for 50%~70% of total resistance. The cleaning effect of water on modified PVC membrane was better than acid or alkali solution. The recovery ratio of membrane flux reached 80%.