单面超疏水单面亲水Janus-CA纤维膜的制备及其油水分离性能

Preparation of superhydrophobic/hydrophilic Janus-CA fibrous membrane and its oil-water separation performance

传统油水分离装置能耗高、操作复杂,针对这一问题,采用等离子体气相接枝的方法,将八甲基环四硅氧烷(D4)聚合于静电纺丝制备的醋酸纤维(CA)膜表面,制备单面超疏水单面亲水的Janus型CA纤维膜。利用场发射扫描电子显微镜(FESEM)、X射线光电子能谱仪(XPS)及视频接触角测试仪等对纤维形貌、元素组成及表面接触角进行表征。结果表明:当纺丝液浓度为20 wt%,推注速度为0.20 mm/min,电压为13 kV,接收距离为20 cm时,制备所得纤维较细且粒径分布较为集中;当等离子体处理时间为8 min,功率为80 W时,Janus-CA纤维膜疏水面接触角为150.5°;将8 min、80 W等离子体处理得到的Janus-CA纤维膜用于去离子水和1,2-二溴乙烷混合液的分离,分离率达97.02%±1.25%,且膜通量达(592.59±23.40) L/(m^2·h),在经历5次分离后膜通量仍为(507.94±8.23) L/(m^2·h),分离率为85.06%±0.52%,表明其具有良好的重复利用性。该Janus纤维膜制备工艺简单,分离过程方便,可有效解决油水分离问题。

The traditional oil-water separation device has the disadvantages of high energy consumption and complex operation. To solve these problems, The Janus cellulose acetate(CA) fibrous membrane featured with one superhydrophobic side and the other hydrophilic side was prepared with plasma gas phase grafting by polymerizing octamethylcyclotetrasiloxane(D4) onto the CA membrane prepared by electrostatic spinning. The morphology, elemental composition and surface contact angle of the membrane were characterized by field emission scanning electron microscopy(FESEM), X-ray photoelectron spectroscopy(XPS) and video contact angle tester. The results show that the CA fibers are fine with concentrated particle size distribution under the following conditions: spinning solution concentration 20 wt%, injection speed 0.20 mm/min, voltage 13 kV, and receiving distance 20 cm. The contact angle of the hydrophobic surface of CA fibrous membrane is 150.5° when the plasma grafting time is 8 min and the power is 80 W. The Janus-CA fibrous membrane treated by 80 W plasma for 8 min was used to separate deionized water and 1,2-dibromoethane mixture. The separation rate was 97.02%±1.25%, and the membrane flux was(592.59±23.40) L/(m^2·h). After five separations, the membrane flux of Janus-CA was(507.94±8.23) L/(m^2·h), and the separation rate was 85.06%±0.52%, showing that the membrane has good reusability. The Janus fibrous membrane has simple preparation process and convenient separation process, which can effectively solve the problem of oil-water separation.