Improving the technology of sodium hypochlorite production by seawater electrolysis

Summary

An alternative method of low concentrated sodium hypochlorite production by seawater electrolysis in substitution for sodium hypochlorite produced by the traditional technology from table white salt solution is considered. The results of studying sodium hypochlorite production by electrolysis of the natural Black Sea water, model Black Sea water in comparison with 3% table white salt solution are presented. The effect of physical and chemical parameters of seawater electrolysis on the amount of generated active chlorine was experimentally investigated. The chemical composition and structure of cathodic deposits formed with time during the electrolysis of seawater, decarbonated seawater and 3% table white salt solution were determined. Comparative evaluation of corrosion and electrochemical characteristics of metal-oxide anode coatings (oxide ruthenium-titanium anodes and oxide iridium-ruthenium-titanium anodes) at seawater and 3% NaCl solution is presented. The expediency of producing sodium hypochlorite by seawater electrolysis was experimentally confirmed and the optimal process conditions were determined. The optimal composition of metal-oxide anode coatings used in low concentrated sodium hypochlorite by seawater electrolysis was determined. Based on the results of research and experimental studies the recommendations for the selection of process flow schemes of sodium hypochlorite production by seawater electrolysis in circulating and flow operation modes were prepared, and the sound fields of their application were justified. The technical and economic assessment of the recommended technology was carried out.

Key words

disinfection , sodium hypochlorite , electrolysis , sea water , gaseous chlorine , oxide ruthenium-titanium anode , iridium-ruthenium-titanium anode