正渗透去除地表水中DOM的效能研究

Study of DOM removal in surface water by forward osmosis

采用经砂滤处理后的滆湖水作为原料液,氯化钠溶液作为汲取液,在不同影响因素条件下进行正渗透试验,并对试验后的膜片进行清洗,探究膜污染的可逆性.结果表明:提高汲取液浓度、运行温度及膜面流速均可有效增加膜通量;正渗透对滆水体中的溶解性微生物代谢产物、类色氨酸、类富里酸和腐殖酸四种主要DOM成分均有较好的去除效果,DOC、UV_(254)截留率均在96%以上;短期运行通过水力清洗几乎可以完全恢复膜通量,而长期运行通过超声清洗可以基本恢复全部膜通量,通过分析膜清洗液可知造成膜污染的主要物质为类色氨酸类和类富里酸类物质.

Forward osmosis(FO)filtration was carried out with influent from Ge Lake after sand filtration,and draw solution of sodium chloride.Different factors influencing FO performance were examined and the cleaning process of the fouled membrane was also conducted to investigate the reversibility of the FO membrane fouling.The results showed that increasing the concentration of the draw solution or the operation temperature and membrane surface velocity could enhance the permeate flux.In addition,the FO could effectively remove the main four types of dissolved organic matters(DOM)in Ge Lake,i.e.the soluble microbial metabolites,tryptophan-like substances,fulvic acids and humic acids,with DOC and UV_(254)removal ratios both above 96%.Furthermore,the membrane cleaning performance exhibited that the flux of the fouled membrane in a short-term filtration can be almost fully recovered with just hydraulic washing,while that in a long-term filtration couldn’t be generally recovered with hydraulic washing,but with ultrasonic cleaning.Finally,the membrane elution was analyzed and it was found that the tryptophan-like substances and fulvic acids were key membrane fouling contributors.