煤化工含盐废水纳滤分盐效果研究

Research on the effect of nanofiltration and salt separation in wastewater from coal chemical industry

针对煤化工行业中废水“零排放”的问题,为避免末端产生危废杂盐,对其中一价盐与二价盐进行有效分离是关键所在。对两种国产纳滤膜与两种进口纳滤膜进行了综合评价;结果表明,在进水水质pH为中性、n(Cl^-):n(SO4^2-)的比例在2∶1~1∶1、运行压力为低压条件下,国产A膜对SO4^2-的截留率在98.5%以上,对Cl-的截留率小于0,水通量在可接受范围内,对总硅的截留率在10%~40%,可达到与进口膜基本相同的分盐效果。

This article addresses the problem of"zero discharge"of wastewater in the coal chemical industry,to evade the generation of miscellaneous salts belonging to hazardous waste at the end,and effectively separating the monovalent and divalent salts.It accomplishes a comprehensive evaluation of the inlet water quality and operating parameters in salt separation.Besides,a comprehensive evaluation of two domestic and two imported nanofiltration membranes is carried out.The outcomes reveal that when the pH of the incoming water is neutral,the ratio of n(Cl-)∶n(SO 2-4)is between 2∶1~1∶1,and operating pressure at low pressure,the retention rate of SO 2-4 by the domestic A membrane is higher than 98.5%.Thus,the retention rate of Cl-is lower than 0,and the water flux is within the acceptable range,and the retention rate of whole silicon is 10%to 40%,which can accomplish roughly the same salt separation effect of imported membranes.Consequently,the domestic membrane can be used instead of the imported membrane from the prospect of diminishing investment costs.