膜蒸馏脱盐用超疏水复合膜的研制

Preparation of superhydrophobic composite membrane for membrane distillation desalination

通过溶胶凝胶法和表面涂覆法,先后在PVDF中空纤维膜表面引入亲水SiO_(2)纳米粒子和低表面能PDMS涂层,构建具有高粗糙度、低表面能的超疏水复合膜,并探究SiO_(2)粒径、SiO_(2)溶液涂覆时间、PDMS涂覆时间等条件对复合膜性能的影响。SiO_(2)/PVDF复合膜接触角只有25.8°,而PDMS/SiO_(2)/PVDF复合膜接触角则达到162.3°,膜蒸馏通量约24.5 kg/(m^(2)·h);在60 h质量分数3.5%氯化钠盐溶液膜蒸馏测试中性能稳定,截留率始终保持在99.8%以上.

In this paper,hydrophilic SiO_(2)nanoparticles and low surface energy PDMS coating were successively introduced on the surface of the PVDF hollow fiber membrane through the sol-gel method and the surface coating method to construct a super-hydrophobic composite membrane with high roughness and low surface energy,and explored the effects of SiO_(2) particle size,SiO_(2) solution coating time,PDMS coating time and other conditions on the performance of composite membranes.The contact angle of SiO2/PVDF composite membrane reached 25.8°,the contact angle of PDMS/SiO_(2)/PVDF composite membrane reached 162.3°, and the membrane distillation flux was 24.5 kg/(m^(2)·h).The performance was stable in the 60 h of mass fraction 3.5%sodium chloride solution membrane distillation test,and the rejection rate was kept above 99.8%.