Study of the processes of electrochemical synthesis of alkaline oxidizing agent – sodium ferrate

Summary

Internationally in the process of purifying industrial wastewater containing organics resistant to oxidation advanced oxidation technologies that provide for the use of oxidizing agents that possess extended oxidizing potential are gaining around. Alkaline sodium ferrate solution is one of the most active oxidizing chemicals. Laboratory studies were carried out to investigate the process of sodium ferrate production by electrolytic treatment of strong sodium hydroxide solution (30–40%) in a membrane electrolyzer with a steel anode. It is shown that in the process of 40% solution of sodium hydroxide activation in the membrane electrolyzer with the laminar steel anode for five hours (anode current density 100 А/m², specific quantity of electricity 20.5 A.h/l) the concentration of sodium ferrate in the anolite reached 7.2 g/l. The current efficiency of sodium ferrate output changed from 0.54 during the starting period of the electroactivation treatment to 0.28 at the end of the process. It was determined experimentally that during the storage of sodium ferrate for seven days its concentration in 40% sodium hydroxide solution dropped from 7.2 to 1.8 g/l. The use of sodium ferrate, alkaline oxidizing agent possessing extended oxidizing potential in the process of industrial wastewater disruptive treatment will provide for the significant reduction of resistant to oxidation organics present in it.

Key words

industrial wastewater , physical and chemical treatment , sodium ferrate , membrane electrolyzer , поверхностный сток , electroactivation , sodium hydroxide