UiO-66-NH_(2)与季铵盐协同改性正渗透膜及其对染料废水分离性能

Synergistic modification of forward osmosis membrane with UiO-66-NH_(2) and quaternary ammonium salt and its separation performance for dye wastewater

为了提高正渗透(FO)膜对染料的分离与抗污染性能,采用共混相转化法将聚对氯甲基苯乙烯(PCMS)引入聚偏氟乙烯(PVDF)多孔支撑底膜中,经UiO-66-NH_(2)与PCMS上的氯甲基的亲核取代反应,使UiO-66-NH_(2)均匀地固定在膜表面,进一步通过改进的界面聚合工艺即在其水相溶液中添加苯基三甲基氯化铵(TMPAC),制备同时具有高渗透性能和抗污染性的FO复合膜。对支撑底膜和FO膜的结构和性能进行分析表征,并通过FO装置测试FO膜渗透分离和抗污染性能。结果表明,UiO-66-NH_(2)的引入有效提升了FO膜的亲水性、荷电性及渗透性能,界面聚合工艺中季铵盐的加入极大提升了FO膜的分离和抗污染性能。改性后的FO膜(M2-T)纯水通量可达到22.4 L×m^(-2)×h^(-1),对染料废水中罗丹明6G和橙黄G的截留率可达97.82%和99.84%,经过6 h的罗丹明6G运行后,归一化通量衰减率仅为10.18%,纯水通量恢复率仍有95.66%。

In order to improve dye separation and antifouling performance of forward osmosis(FO)membranes,polychloromethylstyrene(PCMS)was introduced into polyvinylidene fluoride(PVDF)porous supported membranes by a blending phase inversion method,and UiO-66-NH_(2) was evenly fixed onto the membrane surface by nucleophilic substitution reaction between UiO-66-NH_(2) and chloromethyl of PCMS.Moreover,an improved interfacial polymerization process to fabricate FO composite membranes with high permeability and separation performance was performed by adding trimethylammonium chloride(TMPAC)to its aqueous solution.The structure and property of the supported membrane and FO membrane were analyzed,and the permeability separation and antifouling properties of the FO membrane were tested using a forward osmosis device.The results show that the introduction of UiO-66-NH_(2) effectively improves hydrophilic,charge and permeation properties of FO membranes.Meanwhile,the introduction of quaternary ammonium salt in the interfacial polymerization process greatly improves the separation and antifouling performance of the FO membrane.The pure water flux of the modified FO membrane(M2-T)was 22.4 L×m^(-2)×h^(-1),and its rejection to Rhodamine 6G and Orange G in dye wastewater were 97.82%and 99.84%,respectively.The normalized flux decay rate was only 10.18%after 6 hours of Rhodamine 6G separation,and the pure water flux recovery rate still remained 95.66%.