Study On The Electro-Catalytic Oxidation Treatment Of Organic Wastewaters With Ni-Carbon Aerogels Electrodes

In recent years, electro-catalytic oxidation technology has been widely applied to treat organic wastewaters because of its distinctive advantages, such as wide range of applications, high removing rate, simple equipment, safety, easy to use, environmental compatibility, no secondary pollution and so on. Especially for three-dimensional electrode reactor, it has a wide prospect in application of refractory organic pollutants treatment because of its large aera of effective working electrode, good effect of mass transfer, high treatment quantity of wastewater.The preparation and structural properties of carbon aerogels doped with metal nickel (CA-1) has been studied in this paper. We selected graphite and stainless steel plates, which had a good performance but relatively cheap, as the main anode and cathode, CA-1 as particle electrode, composing the three-dimensional electrode reactor. The treatment process of simulated phenol wastewaters and methyl orange wastewaters using CA-1 as particle electrode in a three-dimensional electrode reactor, which was situated on a magnetic stirrer in order to acquire effective dispersion, has been experimentally studied. Factors affecting the removal efficiency were investigated, including voltage, current density, operating time, anode-cathode distance, pH, particle electrode dose, particle electrode type, electrolyte concentration, electrolyte type and initial concentration of the solution. We also analysed the electrochemical oxidation of organic pollutants through chemical and instrumental analysis methods. In addition, we discussed the removal efficiency of different electrolysis reactors. Finally, we got the optimal conditions of electro-catalytic oxidation treatment. We also did repeat cycle experiments in order to test the electrochemical stability of CA-1 in the treatment process.The results showed that the Ni-modified carbon aerogels can improve distinctly its pore volume and specific surface area and enhance greatly capability of electro-catalytic oxidation treatment to phenol wastewaters and methyl orange wastewaters. Under the optimal conditions of electro-catalytic oxidation treatment, the removal efficiency of the initial phenol concentration and chemical oxygen demand (COD) could arrive at 97.4% and 91.3%, respectively, after 50 cycle experiments, the removal efficiency of the initial phenol concentration could still arrive at 95%. While the removal efficiency of the initial methyl orange concentration and chemical oxygen demand (COD) could reach 98.9% and 95.1%, respectively, after 50 cycle experiments, the removal efficiency of the initial methyl orange concentration could still reach 98%. Under the optimal conditions of electro-catalytic oxidation treatment, the removal efficiency of the initial phenol concentration could arrive at 97.4% and 79.2% of three-dimensional electrode reactor and two-dimensional electrode reactor, respectively, which indicated that the removal efficiency of three-dimensional electrode reactor was much better than that of two-dimensional electrode reactor.