KINETICS OF COMBINED CATHODE PROCESSES IN AQUEOUS NACL SOLUTION

Abstract

Investigation of the kinetics of combined cathode processes in the electrochemical synthesis of sodium hypochlorite. Intensification of the process of molecular oxygen reduction in aqueous NaCl solution to improve the electrochemical synthesis of sodium hypochlorite using a gas diffusion cathode. Investigation of the effect of the gas diffusion regime on the kinetics of cathode processes, determination of the ranges of potentials and current densities of combined cathode reactions. Cyclic voltammetry for the study of kinetic parameters of the cathode process using the MTech PGP-550M pulse potentiostat. Iodometric titration to determine the concentration of sodium hypochlorite. ranges of potentials of combined cathode processes in conditions without air supply and with air supply through a gas diffusion electrode the possibility of depolarization by air oxygen of the cathode process using the gas diffusion mode of operation of a porous graphite electrode is shown. total and partial reductions (oxygen reduction and hydrogen evolution) polarization dependences without air supply and with air supply in an aqueous solution of 3 mol/dm³ NaCl are constructed to better understand the effect of air supply on the course of combined cathode processes. The obtained polarization dependences prove that the air supply to the gas diffusion electrode leads to an increase in the limiting density of the oxygen reduction current from 2 to 8 mA/cm², which indicates the prospect of using a gas-diffusion cathode. Changing the nature of the cathode process can significantly reduce the difference in electrode potentials, and by controlling the oxygen supply rate, ClO^– can be impeded to the cathode surface. For the field of electrochemical production, it consists in improving the electrochemical synthesis of sodium hypochlorite by increasing the current efficiency and reducing specific electricity consumption. By changing the nature of the cathode process of hydrogen evolution for the reduction of oxygen brought to the cathode-electrolyte interface using a gas diffusion cathode, the problem of cathode reduction of ClО^– will be solved without contamination of the final solutions of sodium hypochlorite.