Research On Improving Cathodic Reduction Of Oxygen For In-situ Production Of Hydrogen Peroxide

Hydrogen peroxide has strong oxidizing property, and could generate hydroxylradicals under the activation of Fe2+or ultraviolet, so it has widely used in theenvironmental fields. It is very necessary to produce high concentration of hydrogenperoxide in situ, because hydrogen peroxide is expensive, unfavorable long-distancetransportation and unstable.In this paper, cathodic reduction of oxygen was used to produce hydrogen peroxide,and the experimental device was designed and manufactured by myself. Drawinglessons from the fuel cell method, the gas diffusion cathode was put forward and gotsome improvements, also explored the production process. At the same time, thecathode performance was studied, and found that the new cathode had a domesticationprocess, and what was more, the voltage was under a fluctuating status during theoperation. To improve the cathode performance, the four main production conditionswas optimized, and for the damaged cathode, it was necessary to study the method ofcathode recycle because of the high cost. The cathode performance was significantinfluenced by operating conditions of the experimental device, so it was needed to studyevery operating condition under the best production conditions, and the operatingconditions included Nafion117membrane, current density, electrode spacing, initial pH,electrolyte concentration and air flow. At last, it was studied the effect of long-runningcycle electrolysis under the best operating conditions.From the results of cathode operating, it could be seen that the cumulativeconcentration of hydrogen peroxide was increasing with the electrolysis time extending,but the rate of increase was smaller and smaller, and finally tended to a stable value inthe vicinity. At the same time, the current efficiency was gradually decreased with theelectrolysis time extending.From the results of cathode production conditions, the cathode performance wasbest under the conditions of hot-pressing pressure10MPa, calcination temperature300?, PTFE dosage30%and no pore-forming agent additive, and the cumulativeconcentration of hydrogen peroxide was increased to11923.03mg/L, the currentefficiency was gradually decreased to43.90%after60min electrolysis under theseconditions.From the results of cathode recycle, high temperature calcination method wasbetter, and the cathode performance was close to a new one, and the cumulativeconcentration of hydrogen peroxide was increased to11765.02mg/L, the currentefficiency was gradually decreased to43.29%after60min electrolysis under these conditions.From the results of the electrolytic device operation parameters, the best conditionswere existing Nafion117membrane, current density60mA/cm2, electrode spacing1cm,initial pH=0.5, electrolyte concentration0.10mol/L and air flow40mL/min. Thecumulative concentration of hydrogen peroxide was increased to20096.05mg/L, andthe current efficiency was gradually decreased to63.37%after60min electrolysis underthe best conditions.From the results of the long-running cycle electrolysis, the best circular flow was15mL/min, and after12h electrolysis, the cumulative concentration of hydrogenperoxide was increased to46042.43mg/L, and the current efficiency was graduallydecreased to43.21%.