Electrogeneration of Hypochlorite Ions using a Dimensionally Stable Anode-Type (Ti/PtPd(10%)Ox) Electrode

Abstract

<p>The study examined the electrogeneration of hypochlorite ions (ClO<sup>−</sup>) via electrolysis of aqueous NaCl solutions using a dimensionally stable anode-type (DSA-type) electrode based on platinum and palladium oxides supported on titanium mesh (Ti/PtPd(10%)O<sub>x</sub>). The electrogenerated ClO<sup>−</sup> was quantified on the basis of the absorption band at 292 nm (A<sub>λ</sub> = 292) of the UV-Vis spectrum. The effect of initial pH, concentration of NaCl, cell potential difference and electrolysis time were investigated in this study. The results showed that the electrolysis of aqueous NaCl solutions increases the solution pH up to high values (≥ 8.0) that favor the formation of ClO<sup>−</sup> over chlorine or hypochlorous acid. The hypochlorite concentration increases significantly at pH values > 7.0 and shows a linear trend with increasing NaCl concentration and with increasing cell potential difference. When the cell potential and NaCl concentration are held constant, the maximum hypochlorite value during electrolysis depends on both the cell potential and NaCl concentration. The Ti/PtPd(10%)O<sub>x</sub> anode favors the production of hypochlorite ions, making this anode a promising material for use in electrochemical oxidation of wastewater via an indirect mechanism.</p>