Chloride behaviour in electromembrane treatment of brine issued from desalination plants

Abstract

In this work, the chloride behavior through an electrochemical treatment of brines is examined using ion exchange membranes like in electrodialysis. All experiments have been performed using solutions of NaCl before an application on real brines issued from an Algerian desalination plant. After checking oxidation parameters of chloride oxidation by electrolysis, ion exchange membrane have been introduced to control both the pH and the species migrated. The effect of current density and the membrane nature has been studied. The electrochemical treatment described in this work allows transforming the brines in useful products as NaOH, HCl and Cl₂. The pH and the salt concentration are varied and the products obtained at the electrodes were identified and analyzed. It was shown that we can get chlorates according to the current density applied and the fixed pH. This fact gives rise to an economical process where valuable products can be obtained using only the chloride oxidation current. Results were linked to the Pourbaix diagram and allow the prediction of the process efficiency.