氧化石墨烯改性PVDF/PET复合膜的制备及其抗污染性能

Preparation and antifouling performance of graphene oxide modified PVDF/PET composite membrane

采用PET编织管作为复合膜的结构层,将PVP和氧化石墨烯(GO)分别作为制孔剂和改性剂与PVDF基材混合,通过涂覆-浸没凝胶相转化法制备得到具有亲水性的高强度PVDF/PET编织管复合膜。观察复合膜的断面结构和表面形貌,测定其纯水通量、表面基团以及接触角等性能参数,并将不同浓度GO改性复合膜应用于序批式膜生物反应器(SMBR)中。利用原子力显微镜(AFM)及自制的污染物胶体探针测定了溶解性微生物产物(SMP)与膜面之间的微观作用力,考察改性复合膜的抗污染特性。在40 d的反应器运行实验中,GO改性复合膜的清洗周期较改性前延长了20%~40%,该结果说明改性复合膜能够有效抑制膜面对污染物的吸附,且GO质量分数为0.5%时清洗周期最长。AFM测试结果显示,复合膜中GO质量分数为0.5%时,SMP与膜面之间的黏附力最小,抗污染能力最强。

The poly（vinylidene fluoride） （PVDF）/PET composite membrane with high-strength and hydrophilicity was prepared by coating and immersion phase-inversion method. The PET fiber woven tube was used as supporting layer of the composite membrane. Polyvinylpyrrolidone （PVP） and graphene oxide （GO） were used as pore-forming agent and hydrophilization modifier, respectively. Cross-section structure and surface morphology were observed through SEM and AFM images, respectively. Other performance parameters including pure water flux, surface functional groups and contact angle were also determined. The modified composite membranes with different GO concentration were used in the sequencing membrane bioreactor （SMBR）. To investigate the anti- fouling properties of the composite membrane further, the adhesion force between SMP and membrane surface were determined by atomic force microscope （AFM） equipped with self-made foulant probes. During 40 days running, the cleaning cycle of modified composite membrane was extended by 20% to 40%. The results showed that the modified composite membrane can effectively inhibit the adsorption of SMP on membrane surface. The longest cleaning cycle was obtained when the mass fraction of GO in the composite membrane was 0.5%. Also, the lowest adhesion force between SMP and modified composite membrane was observed through AFM test results, indicating the strongest antifouling ability.