一步法制备Janus中空纤维膜及其膜蒸馏性能研究

Preparation of Janus hollow fiber membrane via one-step strategy and study on its membrane distillation performance

利用亲水改性材料与聚偏氟乙烯共混配制铸膜液,通过正丙醇水两次凝胶调控相转化过程,促进亲水性聚合物向中空纤维内表面偏析,从而改变了膜两侧亲疏水性结构,制备出具有非对称浸润性的Janus中空纤维膜,考察亲水性聚合物添加量等因素对膜性能的影响.所制备的Janus中空纤维膜外侧水接触角超过135°,内侧水接触角约为55°.在原料液温度60℃、渗透液温度10℃情况下,直接接触式膜蒸馏(DCMD)过程渗透通量约为35kg/(m^(2)·h).200 min连续实验中盐截留率始终保持在98%以上.

The hydrophilic material is blended with polyvinylidene fluoride to prepare the membrane casting solution.By regulating the phase inversion process,promoting the segregation of hydrophilic polymer to the inner surface,changing the structure of both sides of the hollow fiber membrane,the Janus hollow fiber membrane with asymmetric wettability was prepared,and the influence of the concentration of hydrophilic material added in the membrane casting solution was explored.The prepared Janus hollow fiber membrane has an outer side water contact angle of more than 135°,and an inner side water contact angle of about 55°.When the temperature of feed water is 60℃and the permeate water is 10℃,the permeation flux of the direct contact membrane distillation(DCMD)process is about 35kg/(m^(2)·h),and the salt rejection rate is 99.9%.In the 200-min continuous DCMD experiment,the salt rejection rate of Janus hollow fiber membranes always remained above 98%.