疏水改性多孔陶瓷管在膜蒸馏中的应用及传质分析

Application and Mass Transfer Analysis of Hydrophobically Modified Porous Ceramic Tubes in Membrane Distillation

中文关键词: 陶瓷管  疏水改性  膜蒸馏  传质

英文关键词: ceramic tube  hydrophobic modification  membrane distillation  mass transfer

中文摘要:

      以全氟癸酸丙烯酸酯(PFDA)为反应物单体,以过氧化二叔丁基为引发剂,采用引发式化学气相沉积技术对Al₂O₃陶瓷管进行疏水化处理。并利用钨灯丝扫描电镜、水接触角测定仪、LEP测试装置等对改性陶瓷管进行表征。结果表明,镀层成功聚合到陶瓷管表面,改性陶瓷管表面达到超疏水级别；疏水改性前后陶瓷管表面形貌和结构没有发生明显变化。疏水改性后的陶瓷管应用于气隙式膜蒸馏实验,随着料液侧与渗透侧温差的增大,渗透通量呈指数型增长。水蒸气在陶瓷管孔隙内的传质系数实验值与理论值相符。

英文摘要:

      The porous ceramics were rendered hydrophobic via initiative chemical vapor deposition (iCVD), applied by a conformal coating of poly(1H,1H,2H,2H-Perfluorodecyl acrylate) (PFDA). The scanning electron microscope (SEM) confirmed that the morphology and structure were kept the same when comparing the images of the modified porous ceramics with those of the corresponding original ceramics. The water contact angle values of the modified porous ceramics were 154 °, which showed superhydrophobic character. The results of the air gap membrane distillation (AGMD) tests showed that the hydrophobic porous ceramics can be applied in membrane distillation. With the increase of the feed temperature, the permeate flux increased exponentially. The higher permeate flux (3.5 kg/m2/h) was achieved at the feed temperature of 80 ℃, the flow rate 1.2 L/min. The permeate flux remains nearly constant and salt rejection rate larger than 99.9% within 20 h operation process of the system. The experimental value of the mass transfer coefficient of water molecules in the pores of the ceramic membrane agreed with the theoretical value.