溶剂对水处理用PVDF微孔膜结构性能影响

利用N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)、磷酸三乙酯(TEP)和二甲基亚砜(DMSO)4种溶剂制备PVDF微孔膜,考察溶剂对成膜性能的影响,除了测试膜结构、孔隙率、清水通量等常规指标外,增加膜污染速率指标,研究4种溶剂成膜在实际膜-生物反应器(MBR)内的运行情况,得到4种溶剂成膜结构不同,具有贯穿性指状孔的DMSO溶剂成膜具有最高的孔隙率,高清水通量,并在MBR内表现出最低的污染速率,最适于制备水处理用的PVDF膜;具有海绵状孔的TEP溶剂成膜具有最高的清水通量,高的孔隙率,在MBR内污染速率较低;DMF、DMAc溶剂成膜结构类似,具有不贯穿的指状孔,孔隙率及清水通量均较低,膜污染速率高,不适于水处理MBR用膜。

EFFECTS OF DIFFERENT SOLVENTS ON STRUCTURES AND PERFORMANCES OF PVDF MEMBRANES USED FOR WATER TREATMENT

Poly(vinyldiene fluoride)(PVDF) membranes using four solvents N,N-dimethylforamide(DMF),N,N-dimethylacetamide(DMAc),Triethyl phosphate(TEP) and dimethylsulfoxide(DMSO) were prepared by phase inversion process.The membrane structures,porosity and pure water flux were tested,together with the membrane fouling rate in an membrane bioreactor(MBR).It was found that prepared membranes had different structures due to the different solvents.The membrane prepared from DMSO showed the highest porosity and pure water flux which had a finger-like structure throughout the cross-section.That membrane was considered as the most appropriate membrane used for water treatment because it had a lowest fouling rate in an MBR.In addition,the membrane prepared from TEP had a sponge-like structure and also showed a high porosity and pure water flux.Meanwhile,the TEP membrane had a relatively low fouling rate.As for the membranes prepared from DMF and DMAc,they both presented a similar structure,the finger-like hole existing near membrane surface.Meanwhile,the porosity and pure water flux of both membranes were low and a high fouling rate was showed in an MBR.Therefore,the membranes prepared from DMF and DMAc were not suit for water treatment in an MBR.