Investigation Of The Mechanisms Of The Simultaneous Removal Of Organic Matter And Heavy Metals Via Micellar Enhanced Ultrafiltration With Mixed Surfactants

The organics and heavy metals in the water body have posed great threat to theenvironment and human health. Micellar enhanced ultrafiltration (MEUF) is a newmethod of membrane treatment, which can remove organic contaminants and heavymetals simultaneously. In this study, a kind of organic matter methylene blue (MB)and a kind of heavy metal cadmium ion (Cd2+) were removed simultaneously viaMEUF to study its feasibility and efficiency. The mechanisms were studied deeply.The results showed that the critical micelle concentration (CMC) of mixed surfactantswas lower than that of using single SDS, and the more amount of TritonX-100led tolower CMC value. But at the same time, more amount of TritonX-100tended to causelower permeate flux and server membrane fouling. In a certain range, using mixedsurfactants obtained higher rejection of both MB and Cd2+due to lower CMC andhence more micelles in the solution for MB to solublized in and Cd2+to bind on.However, too much of TritonX-100would decrease the rejection of MB and Cd2+as aresult of micelle transformation caused by excessive amount of micelles. Higherrejections of MB and Cd2+were obtained when removing them simultaneously thanthat of removing them separately. The addition of Cd2+could reduce the CMC valuesof the surfactants and hence increase the micelle amount in the solution, which led tohigher distribution coefficient of MB. The addition of MB in the solution can also ledto increased distribution coefficient of Cd2+.The study results turned out that it isfeasible to remove MB and Cd2+simultaneously via MEUF, and the coexistence ofMB and Cd2+had no negative influence on the removal of each other; on the contrary,it can promote the removal of each other.The use of mixed surfactants can not only reduce the usage of the amount ofsurfactants, decreasing the cost, but also reduce the surfactant concentration in theretentant, reducing the second pollution caused by the surfactants. Simultaneouslyremoval of organic matter and heavy metals is of significance, which laid a solidfoundation for the application of MEUF in real water treatment, and provides thetheoretical foundation for simultaneous removal of organic matters and heavy metals.