Study On The Preparation Of Chlorine Dioxide By Electrochemical Chemical Coupling Method

Chlorine dioxide disinfectant has been widely used in urban drinking water,military,air haze prevention,agriculture,medicine,food processing,paper making,etc.This paper presents a novel method for the preparation chlorine dioxide:electrochemical-chemical coupling method,which uses oxygen cathode electrolysis to generate H2O2 and react with sodium chlorate dissolved in sulfuric acid solution to prepare chlorine dioxide,which can reduce the transportation and storage costs of hydrogen peroxide and eliminate safety hazards.The main research contents include:(1)The MN/C porous carbon prepared by template method was used as the cathode catalyst for the electrochemical production of hydrogen peroxide.The optimal conditions for preparation were the choice of metal salt(NH4)6MO7O24·4H2O,the content of ammonium molybdate in the raw material,the mass percentage of Mo element in C was 20%,the addition amount of dicyandiamide was 0.1 g,and the choice of calcination temperature was 850?.The optimal catalyst MoN/C-(10)has a minimum electron number of 2.71.(2)Conductive carbon black 72R was modified by hydrothermal method,and the optimal hydrothermal reaction conditions were determined as follows:50 mg 72R carbon powder,2 g glucose and 10.1 g KOH reacted at 180? for 8 h.Infrared and XPS analysis of the obtained catalyst confirmed that hydrothermal reaction increased the oxygen-containing functional groups on the surface of the carbon material.Electrochemical test results showed that under alkaline conditions,the cyclic current density could reach 0.84 mA/cm2,the initial potential was 40 mV earlier than 72R,and the number of electrons transferred was n=2.41.(3)The catalysts prepared by the two methods were applied to the electrolytic cell.The Faraday efficiency of MoN/C-(10)prepared by template method could reach 60.3%under the alkaline condition and 46.9%under the neutral condition.Under O-72R alkaline condition,the efficiency of electrolysis Faraday can reach 97.0%and 91.2%under neutral condition.At the same time,O-72R was tested in a cycle and for a long time.The Faraday efficiency could be maintained above 95%after 5 cycles of the same electrode,and above 90%after a long test at 50 h,which provided the possibility for industrial application.(4)Chlorine dioxide was prepared by electrochemical-chemical coupling method,and O-72R was used as the cathode catalyst for electrolysis experiment.When the optimal temperature was 50?,the ClO2 production rate reached 176.4 mg/h,and the tank pressure was 2.31 V.When the optimal current density is 150 mA/cm2,the ClO2 production rate can reach 319 mg/h.Finally,24 h long time experiment was conducted to investigate the stability.The electrolytic cell pressure could maintain the stability for 24 h,and the cumulative ClO2 production was 10.64 g,with an average generation rate of 443 mg/h,providing a new idea for the industrial production of ClO2.