膜科学与技术

DVB改性超疏水纤维膜及其在膜蒸馏中的应用

作者：从硕，董建华，郭飞

单位：大连理工大学能源与动力学院，海洋能源利用与节能教育部重点实验室，辽宁大连 116024

关键词：聚丙烯腈；静电纺丝；疏水改性；膜蒸馏；脱盐

出版年,卷(期):页码： 2018,38(5):104-112

摘要：

本文以安全无毒的低能量单体二乙烯基苯（Divinylbenzene，DVB）取代1H,1H,2H,2H-全氟癸基丙烯酸酯（1H,1H,2H,2H-Perfluorodecyl acrylate，PFDA），作为引发式化学气相沉积的前驱材料，成功将通过静电纺丝技术制备的聚丙烯腈（PAN）纤维膜由亲水膜改性为超疏水膜，并应用于膜蒸馏中。采用扫描电镜、水接触角测量仪、LEP测试装置、原子力显微镜等对改性前后纤维膜的表面形貌、润湿性、水力穿透压、厚度变化等参数进行表征。将改性后的纤维直径在0.23~0.81 μm的PAN纤维膜用于气隙式膜蒸馏实验。结果表明，静电纺丝纤维膜呈无纺结构，疏水化改性后纤维膜形貌无明显变化，料液侧与渗透侧温差为13~59 ℃时，渗透通量为1.5~22 kg/m2/h，脱盐率均在99.9 %以上。随着纤维丝直径减小，孔隙率、水接触角，以及水力穿透压均有增加。纤维直径对膜蒸馏过程中的渗透通量、脱盐率和水力穿透压起到重要作用。

Divinylbenzene (DVB) is a kind of low-energy monomer which is also environmental friendly. In order to replace 1H, 1H, 2H, 2H-perfluorodecyl acrylate (PFDA), DVB was used as the precursor for initiated chemical vapor deposition (iCVD). In this study, Polyacrylonitrile (PAN) fibrous membranes were prepared by electrospinning. The membranes were transferred from hydrophilic to superhydrophobic by iCVD, and successfully applied in membrane distillation. The morphology, wettability, liquid entry pressure (LEP), and thickness of the membranes were characterized by scanning electron microscope, water contact angle measurement instrument, LEP test equipment, and atomic force microscopy (AFM). A set of iCVD treated PAN fibrous membranes with the fiber diameters ranging from 0.23 μm to 0.81 μm were tested for membrane distillation using a lab-scale air gap membrane distillation unit. The electrospun fibers were found to be randomly oriented. The morphology of fibrous membranes after surface modification showed no obvious change. The permeate flux was 1.5~22 kg/m2/h when the temperature difference between the feed solution and condensing plate was 13~59 ℃. The salt rejection ratios were all larger than 99.9 %. With decreasing the fiber diameter, the liquid entry pressure, the water contact angle, and the porosity were observed to increase, from 49 kPa to 128 kPa, from 84 % to 89.5 %, from 137 ° to 147 °, respectively. The results show that the fiber diameter plays an important role in the MD performance in terms of permeate flux, salt rejection ratio, and liquid entry pressure.

第一作者简介：从硕（1994—），男，安徽宿州人，博士研究生，研究方向：薄膜蒸馏。通讯作者：郭飞（1983—），男，教授，博士生导师。研究方向：先进膜材料，碳素纳米材料。 E-mail: feiguo@dlut.edu.cn.

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