膜法海水提溴用PVDF中空纤维膜的研制

Preparation of PVDF hollow fiber membranes for bromine extraction from seawater

采用相转化法制备海水提溴用疏水性聚偏氟乙烯中空纤维膜,考察聚合物浓度、无机复合添加剂浓度、膜干燥方式及后处理方法对膜结构和性能的影响.结果表明,无机复合添加剂能有效提高膜机械性能,同时不影响膜疏水性;溶剂置换法不能完全避免膜收缩,从而直接影响膜孔结构和透气性能.物理后处理方法可显著提高膜透气性能,氮气通量为8.62 m3/(m2.h),孔隙率为63.31%,膜断裂强度可达到1.64 cN/Tex,膜断裂伸长率为79.10%.

Hydrophobic PVDF hollow fiber membranes for the bromine extraction from seawater were prepared by phase inversion method. The effects of membrane preparing conditions, such as PVDF concentration, composite inorganic additive concentration, drying methods and post-treatments on membrane structure and performance were investigated. The results show that composite inorganic additive nearly would not affect membrane hydrophobicity, but could improve membrane mechanical property. Solvent-replacement methods could not completely prevent membrane shrinkage, which directly affecting membrane pore structure integrity and membrane permeability. Physical post-treatment was used to improve membrane permeability apparently. The Membrane N2 flux and porosity were 8. 62 m3/（m2 - h） and 63.31% respectively, breaking strength was 1.64 cN/Tex and breaking elongation was 79.10%.