The Study Of Recovery Of Cd²⁺ By An Electrolytic Process From The Concentrated Solution Of Micellar Enhanced Ultrafiltration

The high toxicity of metal cadmium on human,plangts and animals can be extremely harmful. Wast waters containing dissolved cadmium come from many sources such as electroplating industries, nonferrous metals smelting,mine tailing. Micellar enhanced ultrafiltration(MEUF) is a new method which is based on the surfactant of the unique characteristic of parental molecular structure that can remove low concentration heavy metals in the water.It is a technology that combined the surface active agent with ultrafiltration. Compare with the traditional ultrafiltration, MEUF has many advantages.Such as lessen cost, and more effective removal of cadmium ions.Meanwhile,MEUF compared to the method of adsorption,distillation and extraction that has low energy consumtion and no intercsction.The most important is the treated water from MEUF can be directly recycled. But the concentrated solution by dealing with the MEUF contains high concenttation of heavy meatal ions and surface active agent,so it must be need to further processing for revovering heavy metals and recycling surface active agent.In this study, the electrolysis method was employed to recovery Cd2+ from the concentrated solution of MEUF..Effects of type of electrode, electrolysis voltage(U) and time(t),solution pH, surfactant to Cd2+ molar ratio ([SDS]/[Cd2+]) on Cd2+ reconery efficiency were investigated.And these five factors were optimized. The optimum experimental conditions were obtained:stainless steel(anode)- graphite(catho-de),U=2V,t=100min,pH=4,[SDS]/[Cd2+]=5.And the recovery efficiency of Cd2+ in the concentrated solution was 50.26%.This research also further studied the electrolyte of various substances on the process of electrolysis. The study found that the surfactant has some effect of resistance to electrolysis process. The same conditions in electrolysis, the recovery efficiency of Cd2+ was 50.26% that the solution containing SDS but 72.11% without SDS. Impact on the SDS in the electrolysis experiments,the experimental results showed that SDS concentration had a certain decrease under the action of electrolysis. But did not affect the SDS reuse. Added to the concentrated liquid electrolyte NaCl to enhance the recovery efficiency of Cd2+ experiments, the recovery efficiency of Cd2+ is 60.05% when the concentration of electrolyte NaCl is 0.3mol/L. The recovery efficiency of Cd2+ from 50.26% to 60.05% by adding electrolyte NaCl.