利用低浓度表面活性剂胶团强化超滤处理含锌废水

REMOVAL OF ZINC IONS FROM AQUEOUS SOLUTION USING MICELLAR-ENHANCED ULTRAFILTRATION AT LOW SURFACTANT CONCENTRATIONS

利用低浓度的阴离子表面活性剂十二烷基硫酸钠(SDS),对含Zn2+废水进行了胶团强化超滤(MEUF)研究。结果表明:进料液的静置时间为3h时,Zn2+在SDS胶团上的吸附达到平衡状态。当Zn2+的浓度一定时,由于发生在膜表面的浓差极化现象的影响,在进料液中投加浓度低于1倍临界胶束浓度(CMC)的SDS,不但在很大程度上降低了SDS的用量,而且亦可获得较高的Zn2+截留率和渗透通量,Zn2+的截留率主要受膜表面SDS浓度的影响。随着进料液中SDS浓度的升高,渗透通量逐渐降低,而渗透液中SDS的浓度随之不断增大,但无论进料液中SDS浓度有多大,渗透液中SDS的浓度都不会高于1倍CMC(2.25g/L),所以渗透液中的SDS的损失相对较小。Zn2+截留率随进料液中Zn2+浓度逐步增大而逐渐减小,基于低浓度表面活性剂的胶团强化超滤技术适宜处理低浓度含Zn2+废水。

Micellar-enhanced ultrafiltration （MEUF） of zinc cations （Zn^2＋） from aqueous solutions using anionic surfactant sodium dodecyl sulfate （SDS） at low concentrations was investigated. The Zn^2＋ adsorption to SDS micelle reached equilibrium after 3h. When the initial concentration of Zn^2＋ was constant and the initial concentration of SDS was below the critical micelle concentration, not only the dosage of SDS could be reduced but also the of Zn^2＋ and the permeate flux were high. The retention rate of Zn^2＋ is a function of the SDS concentration at the surface of the membrane. With the increases of the initial SDS concentration, the permeate flux decreased gradually and the permeate concentration of SDS increased. Whatever was the concentration of SDS in the feed, the SDS concentration in the permeate,was lower than CMC. Consequently the loss of SDS was small. The retention rate of Zn^2＋ decreased with the increases of the initial Zn^2＋ concentration. The removal of Zn^2＋ at low Zn^2＋ feed concentrations was very efficient using micellar-enhanced ultrafiltration at low surfactant concentrations.