Metal oxide nanofluids on heavy metals removal by the electrochemical method from refinery wastewater

The electrochemical coagulation process, or EC, is an electrochemical process that direct electrical current was used to remove pollutants from solution. In this paper, the effect of nanofluids of iron, copper, and zinc metal oxides on electrochemical reaction of heavy cobalt metal removal from the refinery wastewater was investigated. Different tests were performed to achieve the best performance with maximum efficiency. In the meantime, the best performance was achieved at 30 volts and 60 minutes having efficiency up to 52%. In the next step, the tests were performed using iron, copper, and zinc nanoparticles oxides that they could been reduced cobalt values to 73%, 87% and 61% of the initial amounts, respectively. Between used metal oxides, the results show iron oxide nanoparticles could reached to maximum cobalt removal from the wastewater, and after that copper and zinc oxides nanoparticles have high removal efficiency, respectively. Surface response method used to determining the optimum cobalt removal conditions. A quadratic statistical model was presented in terms of experimental parameters. The statistical model predictions from experimental design are in good agreement with experimental data for cobalt removal in this work.