Increase in current efficiency during the reduction of chromate ions

This article highlights the influence of glycerol on the current efficiency of chromium during the electrolysis of waste solutions and the determination of the optimal process conditions. Being highly toxic waste, hexavalent chromium ions are formed in wastewater from metallurgical, galvanic, leather industries. The reduction of ions of relatively toxic hexavalent chromium is carried out by various methods, which are divided mainly into two large groups: chemical and electrochemical. Relatively effective methods of purification from chromium (VI) compounds should be recognized as reagent methods based on redox processes. However, these methods also have a number of significant disadvantages: they are characterized by high consumption rates of reagents, are accompanied by the formation of large amounts of sludge deposits and require significant material costs for measures to protect process equipment from corrosion, since they are carried out in a highly acidic environment. Methods of electrochemical treatment of chromate-containing wastewater and solutions, in turn, are divided into cathodic reduction, electrodialysis and electrocoagulation. At the same time, it should be noted that during the electrochemical reduction of chromium ions, the current efficiency of chromium is very low (14-16%), therefore it is advisable to carry out wastewater treatment by the recommended method in hard-to-reach areas, with the formation of wastewater up to 50 m3/h, where it is difficult to regularly import chemicals. The electrochemical method of wastewater and waste solutions treatment is compact and efficient, but with the electrochemical reduction of chromium (VI) ions, the current efficiency of chromium is very low (15-16%), at the same time, this method can purify wastewater from impurities to TLV. In the process of metal reduction, the bulk of the energy is spent on such undesirable processes as ion polarization, precipitation of certain impurities in solution, and electrolyte resistance. In this work, we have carried out studies to increase the degree of reduction of hexavalent chromium ions in the presence of polyhydric alcohols such as xylitol, sorbitol and glycerol. Of these, relatively positive results were shown by trihydric alcohol - glycerol.

Перевод пока недоступен