纳滤膜对邻苯二甲酸二(2-乙基己基)酯截留行为的研究

Research on the rejection of di-(2-ethylhexyl) phthalate by NF

采用聚酰胺复合纳滤膜(BDXN-90)处理地表水中微量邻苯二甲酸二(2-乙基己基)酯(DEHP),研究了有机物、离子强度等因素对其截留行为的影响;探讨了在有机物共存的条件下,纳滤膜截留DEHP的机理.结果表明:BDXN-90纳滤膜能有效截留地表水中微量邻苯二甲酸二(2-乙基己基)酯,其截留率在98%以上,并且长时间运行稳定;膜过滤过程中,刚开始由于DEHP与膜表面之间的吸附截留率较高,当吸附趋于饱和截留率下降,最后随着膜污染的逐渐形成导致膜通量下降和截留率上升;影响截留行为的主要因素是离子强度和有机物:离子强度中和膜表面静电将膜基质压实,有机物与膜表面产生吸附导致膜污染.

Studies were conducted to investigate the effect of organic matters and ionic strength on the rejection of trace DEHP in polyamind composite nanofiltration membrane （BDXN- 90） filtration process, and mechanism of rejection by NF under containing organic matters. Experimental results indicated that the trace DEHP in sur- face water could be rejected very effectively by BDXN - 90 NF membrane, the rejection efficiency is above 98 % and the NF operation circulates steadily during long time. First, the rejection is high because of the adsorption between DEHP and membrane surface. Second, the rejection is declined due to the adsorption reaches saturation. Finally, the membrane permeate flux is decreased and rejection is increased by the membrane fouling. The rejection is influenced mainly by ionic strength and organic matter, the effect on membrane rejection is attributed to a compaction of the membrane matrix resulting from charge neutralization at the membrane surface and adsorption between organic matter and membrane.