(139h) The Kinetics of Chlorine Evolution on Dimensionally Stable Anode (DSA) Used in the Chlor-Alkali Industry

The anodic oxidation of chloride in an acid aqueous media on the DSA leads to the chlorine evolution reaction (ClER) [1]. In our research , we investigate the ClER kinetics by means of Voltammetric curves, Tafel lines and reaction order determinations.

The typical structure of electrodes (DSA) used in kinetic studies consists of a flat support (Ti) Coated with a thick layer of metal oxides from Permascand Company as an industrial electrode. A convenient method with three electrodes system , is used for measuring the ClER rate [2] that is following the change of current density in constant overpotential against the concentration of chloride , using linear sweep voltammetry technique with potentiostat/Galvanostat Autolab (Metrohm) model , PGSTAT 30 .The kinetic experiments of the ClER were carried out in pure chloride solutions and To obtain a value of the ClER rate costant , the concentration of chloride ions were ranged between (0.5 - 5 M) and changes in the pH values were performed by addition of HCl and maintained between 2-4 , because of in the limited range , the ClER is the main electrode reaction . The rest potential of the DSA in solution of (H2O + NaCl + HCl) as electrolyte was measured against a saturated calomel electrode (SCE) and was varried out by sweeping potentioal between (0.5?1.2 volt). The activation thermodynamic parameters were determined from the ClER rates measured at temperature range of (30 ? 90 °C ). The mechanism of the ClER on the DSA is complicated by the specific features of the surface [3] ,but on the basis of the experimental result , we tried to propose the mechanism of the ClER on the DSA .