不同内径超滤膜处理海水的分离性能及清洗方案的研究

STUDIES ON THE PERFORMANCE OF UF MEMBRANE WITH DIFFERENT FIBER DIAMETERS FOR SEAWATER PRETREATMENT AND MEMBRANE CLEANING

采用相同截留相对分子质量(100×103)、不同内径(1.2mm和1.0mm)的聚氯乙烯中空纤维超滤膜Ⅰ和Ⅱ处理青岛近海域海水,对极端操作条件下(死端模式和无反冲过滤)的膜分离性能以及不同清洗方案和效果进行了对比试验。结果表明,相同操作条件下,膜Ⅱ具有膜污染程度小、膜通量大、清洗效率高等优势;可逆污染去除率R表明,超声波和碱-EDTA的清洗效率更显著,且2者对膜Ⅱ的清洗效率均比膜Ⅰ高。采用扫描电镜和红外光谱分析膜样品,发现膜Ⅰ比Ⅱ膜污染严重;超声波清洗仍无法完全去除膜污染,污染物含有类脂、多糖、腐殖质和木质素等物质。

Experiments of ultrafiltration （UF） for seawater pretreatment were conducted to evaluate the performance and cleaning efficiency of different UF membranes under critical operational conditions including dead-end mode and no backwash. The tested UF I and UF II membranes were characterized the same membrane material （PVC） and molecular weight cut-off （MWCF 100×103） but different fiber inner diameters （1.2 mm and 1.0 mm）. For the seawater collected in Qingdao,the PVC hollow fiber with fiber inner diameter of 1.0 mm has the better performance during filtration with ultrasound and NaOH-EDTA cleaning when compared to the other cleaning protocols and another membrane,and it was proven by the results of R. SEM and FTIR were applied to characterize the membrane fouling and the results showed that membrane fouling of UF I was more obvious than UF II. Membrane fouling can not be removed totally by ultrasound cleaning,and lipoid,polysaccharide,humics and lignin were the main components of membrane fouling.