新型Janus膜的制备及其膜蒸馏性能研究

Preparation of novel Janus membrane and study on its distillation performance

针对传统的静电纺丝纳米纤维膜(ESNM)容易被污染且存在机械稳定性低和膜通量不高的问题,采用静电纺丝和层层组装的方法制备了一种一侧呈超疏水性、另一侧呈亲水性的不对称结构蒸馏膜(Janus膜),其中超疏水层由表面包覆聚二甲基硅氧烷(PDMS)的SiO_(2)微球堆叠而成,其接触角为151°;亲水层由偏聚氟乙烯(PVDF)与聚乙烯醇(PVA)溶液静电纺丝出的纳米纤维组成,其接触角为17°。拉伸实验结果表明,该Janus膜在弹性范围内能承受的最大负荷是未进行表面改性的PVDF膜的3.6倍。直接接触式膜蒸馏实验(DCMD)结果表明,Janus膜的膜通量为29.9 L/(m^(2)·h),截留率为99.9%。

Conventional electrospinning nanofiber membrane(ESNM)is prone to be contaminated,and has the problems of low mechanical stability and low membrane flux.An asymmetric structure distillation membrane(Janus membrane)is prepared through electrospinning and layer-by-layer assembling processes.The superhydrophobic side of the membrane is formed by stacking SiO_(2)microspheres coated with polydimethylsiloxane(PDMS),which has a contact angle of 151°.The hydrophilic side of the membrane is composed of nanofibers electro-spun from a mixed solution of polyfluoroethylene(PVDF)and polyvinyl alcohol(PVA),which has a contact angle of 17°.Tensile test result shows that the maximum load that the Janus membrane can withstand in the elastic range is 3.6 times that of PVDF membrane without surface modification.Direct contact membrane distillation experiment shows that the membrane flux of Janus membrane is 29.9 L/m^(2)·h,and the rejection rate is 99.9%.