烷基硅烷自组装中空纤维膜及膜蒸馏脱盐性能

Alkylsilane Self-Assembled Hollow Fiber Membranes and Membrane Distillation Performance

采用浸没沉积法,借助浸没液中聚偏二氟乙烯(PVDF)的黏结性,将纳米SiO_(2)沉积在膜表面。利用SiO_(2)表面的硅羟基与十八烷基三甲氧基硅烷(OTMS)水解后的硅羟基进行自组装反应,制备了超疏水膜蒸馏用膜。研究了浸没液中PVDF浓度、SiO_(2)含量对膜性能的影响。当PVDF的质量分数为0.3%、纳米SiO_(2)质量分数为0.5%时,改性膜的性能最佳,扫描电镜结果表明,膜表面由PVDF微晶和纳米SiO_(2)组成了多孔连续粗糙结构,接触角达到156.5°,经过180 min超声处理和48 h强碱浸泡,膜表面依然具有超疏水性能。在NaCl和十二烷基硫酸钠(SDS)混合溶液、NaCl和腐殖酸(HA)混合溶液的DCMD测试中,改性膜具有稳定的通量和截留,而原膜在污染物SDS和HA的影响下,通量和截留下降,改性膜具有良好的抗润湿性能和抗污染性能。

The immersion deposition method was used to deposit nano-SiO_(2) on the surface of the membrane with the aid of the adhesion of PVDF in the immersion liquid.The self-assembly reaction between the silanol on the surface of SiO_(2) and the silanol hydrolyzed by octadecyltrimethoxysilane(OTMS)was used to prepare a superhydrophobic distillation membrane.The effects of PVDF content and SiO_(2) in the immersion liquid on the properties of the modified membrane were studied.When the mass fraction of PVDF is 0.3%and SiO_(2) is 0.5%,the performance of the membrane is the best.The SEM results show that the surface of the membrane is composed of PVDF microcrystals and nano-SiO_(2) to form a porous continuous rough structure with a contact angle of 156.5°.After 180 min of ultrasonic treatment and 48 h of strong alkali immersion,the surface of the membrane still has superhydrophobic properties.In the DCMD test of NaCl and SDS mixed solution,NaCl and HA mixed solution,the modified membrane has the stable flux and rejection.Under the influence of pollutants SDS and HA,the flux and retention of the original membrane decrease,and the modified membrane has good anti-wetting and anti-fouling performance.