Experimental study on micellar-enhanced ultrafiltration (MEUF) of aqueous solution and wastewater containing lead ion with mixed surfactants

We studied the performance of single and mixed surfactants for removal of Pb2+ from aqueous solution and wastewater by MEUF. Anionic surfactant, SDS and 2 nonionic surfactants, TX-100 and NP12 were used. The experiments were carried out using a flat sheet module with polyethersulfone membrane (MWCO 10 kDa).Single surfactants, SDS gave high Pb2+ rejections but low SDS rejections while TX-100 and NP12 showed opposite results. The use of mixed surfactants between SDS and nonionic surfactants can effectively enhance both Pb2+ and surfactant rejections. The optimum amount of nonionic surfactants added was at mole fractions of 0.1 for both SDS/TX-100 and SDS/NP12 systems in which the highest Pb2+ rejection can be achieved. At this mole fraction (1.37 mM) of TX-100 and NP12 with 12.3 mM of SDS, the Pb2+ rejections were higher than 98.4%. High rejections of SDS (80%), TX-100 and NP12 (> 99%) were also obtained. The MEUF showed promising results of real wastewater tested.The analysis of transport resistances showed that polarization resistance was dominant and fouling was very low for both single and mixed surfactants. Fouling resistances of mixed surfactants were higher than that of pure SDS but lower than those of pure nonionic surfactants.