摘要
采用"挤出-压延-拉伸"法,通过改变纵向拉伸倍数,制备出平均孔径为0.25～0.80μm,孔隙率为46.9%～78.3%的4种疏水PTFE平板微孔膜。制备得到的PTFE平板微孔膜具有"纤维-结点"的网状微孔结构。随着纵向拉伸倍数的增加,微孔膜结构中的结点变小,纤维变细,孔径和孔隙率增大,孔隙分布更均匀。分别以茶多酚水溶液和CaCl2溶液为进料液和渗透液,进行渗透蒸馏浓缩实验。研究了膜孔径、渗透液和进料液的浓度、流速等对渗透通量和截留率的影响。结果表明,增大PTFE平板微孔膜孔径、提高渗透液的浓度以及进料液和渗透液的流速可提高渗透通量。整个实验过程中,4种PTFE平板微孔膜对茶多酚的截留率均能保持在99.9%以上,且不受操作条件的影响。
Polytetrafluoroethylene （PTFE） hydrophobic flat-sheet membranes were prepared through a cold pressing method including paste extrusion, rolling and stretching. The mean pore diameters and porosities of the prepared PTFE fiat-sheet membranes varied from 0.25 to 0.80 μm and from 46.9% to 78.3%, respectively. The PTFE fiat-sheet membranes showed the microstructures of nodes interconnected by fibrils. The nodes became small and the diameters of fibrils decreased with the increase of stretching ratio. Increasing stretching ratio increased the pore size and porosity of the PTFE flat-sheet membrane. The effects of pore size, the concentrationsof osmotic solution and feed, and the flow rate of osmotic solution and feed on flux and tea polyphenols rejection were investigated in the experiment of osmotic distillation with the solution of tea polyphenols and CaCI2 as the feed and osmotic solution, respectively. The results indicated that the increase of pore size of PTFE fiat-sheet, concentration of osmotic solution, and flow rate of osmotic solution and feed can improve the permeation flux. In this study, the tea rejection achieved 99.9% for all the PTFE flat-sheet membranes with four stretching ratio. The operation conditions have little effects on the tea rejection.
出处
《水处理技术》
CAS
CSCD
北大核心
2014年第1期43-46,共4页
Technology of Water Treatment
基金
国家科技支撑计划(2013BAC01B01)
国家高技术研究发展计划(863)项目(2013AA065003)
教育部新世纪优秀人才支撑计划(NCET-10-0980)
浙江省重大科技专项重大社会发展项目(2012C13006-2)
浙江理工大学博士启动基金(1113808-Y)
关键词
PTFE平板膜
渗透蒸馏
茶多酚
PTFE fiat-sheet membrane
osmotic distillation
tea polyphenols
