基于膜蒸馏技术的PTFE中空纤维膜处理印染反渗透浓水

VACUUM MEMBRANE DISTILLATION FOR TREATMENT OF REVERSE OSMOSIS CONCENTRATES GENERATED IN DYE WASTEWATER BY USING PTFE HOLLOW FIBER MEMBRANE

通过调节挤出头的尺寸和拉伸倍数,制备出4种不同壁厚和孔径的聚四氟乙烯(PTFE)中空纤维膜。采用真空膜蒸馏(VMD)技术处理印染反渗透(RO)浓水,研究了壁厚和孔径、料液温度、浓缩倍数等对处理效果的影响;并进行了连续运行20 d测试。结果表明,减小膜丝壁厚、增加膜孔径和料液温度均可增加产水通量,浓缩倍数增加会降低产水通量;产水通量随工作时间的延长而减小,膜丝经HCl水溶液清洗后,产水通量能恢复至初始通量的95%以上;产水TDS、COD和色度的去除率均保持在95%以上。

Four kinds ofpolytetrafluoroethylene （PTFE） hollow fiber membranes with different wall thicknesses and pore sizes were prepared through changing the parameters of extrusion head and stretching ratios in this paper. The effects of wall thickness, pore size, feed temperature and concentration times on the permeate flux and production indicators were investigated by means of vacuum membrane distillation （VMD）. The experimental results showed that the permeate flux increased with the decrease of wall thickness. Increasing the pore size of PTFE hollow fiber membrane and feed temperature were positive for the permeate flux. However, the permeate flux decreased with the increase of concentration time. The continuous tests in 20 d showed that the permeate flux decreased with the extension of working time. However, the permeate flux recovered to over 95% of the initial permeate flux after washing by the HCl solution. The rejections of TDS, COD and chroma in the permeate were more than 95%.