Micellar-enhanced ultrafiltration of cadmium and methylene blue in synthetic wastewater using SDS

Single and simultaneous removal of Cd2+ and methylene blue (MB) with sodium dodecyl sulfate (SDS) by micellar-enhanced ultrafiltration under different experimental conditions was investigated. In single removal process, with initial SDS concentration increasing, the removal efficiency of Cd2+ and MB kept increasing and then decreased. When the initial concentrations of SDS and Cd2+ were 1.0 cmc and 50 mg L−1, respectively, the maximum removal efficiency of Cd2+ was obtained as 99.2%. Removal efficiency of MB could achieve more than 99.9% with initial SDS concentration below 2.0 cmc. As compared with single Cd2+ removal, the removal efficiency of Cd2+ in the presence of MB was slightly higher with initial SDS concentration below 1.0 cmc, while decreased with the SDS concentration above 1.0 cmc. The maximum removal efficiency of Cd2+ was 98.8% when initial concentrations of SDS and MB were 1.0 cmc and 4 mg L−1, respectively. The removal efficiency of MB in the presence of Cd2+ could achieve higher than 96.5%, which was only 3.4% less than the optimum result of the single removal. Meanwhile, effect of pH on removal efficiency of Cd2+ was more significant than that of MB.