Hypochlorite production on Ru‐Sn binary oxide electrode and its application in treatment of dye wastewater

Abstract

AbstractRuthenium‐tin binary oxides [(Ru+Sn)O2] were coated on titanium substrates by thermal decomposition. The surface morphologies and elemental analyses of these electrodes were examined by means of scanning electron microscopy. The electrochemical behaviours were characterized by cyclic voltammetry and linear‐scan voltammetry (LSV) methods. The effects of electrolysis condition for the current efficiency (CE) of hypochlorite production on binary (Ru+Sn)O2 electrodes and the treatment of a high salt‐containing dye wastewater using this hypochlorite were also investigated. The highest CE for hypochlorite production exists on an RS3 (40 to 80 mol% Sn in coating solution) electrode. The major factors influencing CE for hypochlorite production are the electrolyte flow rate, current density, and chloride (Cl‐) concentration. Major factors affecting energy yield are current density, Cl‐ concentration, and electrode distance. For low current density (300 mA.cm−2), high Cl‐ concentration (1 mol.L−1), and 0.45 cm electrode separation, a high specific energy is obtained. The RS3 electrode exhibits the best removal of organics and chromophor groups in the dye wastewater. On this electrode, better removal of organics and chromophor groups is obtained at 300 mA.cm−2. The colour of black‐red dye wastewater becomes light yellow when a charge of 792 A·min was passed, while the chemical oxygen demand (COD) of this wastewater is decreased from 10500 mg.L−1 to 1250 mg.L−1.