Electro-catalytic Oxidation Of Organic Pollutants

In order to solve the problems of refractory,high toxicity and serious pollution of phenol wastewater in the industry,this paper adopts an advanced electro-catalytic oxidation method,which uses Ti/IrO2-RuO2 as anode and titanium plate as cathode to treat phenol wastewater.In this paper,the optimal experimental conditions for electro-catalytic oxidation of phenol xwere obtained by changing the different conditions.The final chemical oxygen demand(CODcr)under the optimal reaction conditions was calculated.The reaction process kinetics was studied based on the single factor experimental data.Study the influence of different conditions on the rate constant k.The kinetic model of the rate constant k was simulated.The intermediate products in the process of electrolyzing phenol were detected,and the reaction process and mechanism were inferred.The whole energy consumption was calculated.The concentration of phenol wastewater and the CODcr after the final reaction were under the national primary discharge standard.The main research contents and conclusions are as follows:(1)The single factor experiment was carried out by changing the different conditions and the CODcr of the wastewater was determined by the potassium dichromate method.The results showed the optimum reaction conditions of electro-catalytic oxidation of phenol were that the initial concentration of ph enol was 50 mg/L,the current was 4 A,the concentration of electrolyte Na2SO4 was 0.05 mol/L,the pH was 6,and the reaction time was 3.5 h.The removal rate of phenol was up to 96.09%,the final CODcr can reach 36.33 mg/L.(2)The kinetics of the electrocatalytic oxidation of phenol was investigated.The results show that when the reaction conditions are different,the reaction order has zero and one order;when the reaction accords with the zero-order reaction kinetics,I can f-ound that increasing the current value can increase the rate constant k;with the increase of the electrolyte Na2SO4 concentration,the rate constant k value increased firstly and then decreased,the increase o f initial concentration of phenol can increase the rate constant k;the pH value of the solution has little effect on the reaction.Finally,the kinetic model of k was established,and due to the order of the kinetic model's indexes,the effect size of different reaction conditions was:initial concentration of phenol>current>electrolyte Na2SO4 concentration.(3)The intermediate products by were detected by high performance liquid chromatography and inferred speculation of possible reaction processes and reaction mechanisms.The results showed that the main intermediate product was benzoquinone.There are two main mechanisms of the oxidation of phenol.One is that the hydroxy compound attacks the phenol to form a benzene ring by a hydroxyl radical;the other is that a phenolic oxygen radical combines with a hydroxyl radical to form a benzene ring.(4)Analysis of voltage and energy consumption.It was found that the voltage was stable after 90 minutes of reaction;the energy consumption of the reaction was 0.0005444(kW·h mg-1).