Hypochlorite generation on Ru-Pt binary oxide for treatment of dye wastewater

Ruthenium-platinum binary oxides [(Ru + Pt)O-x] were coated on titanium sub strates by thermal decomposition. The surface morphologies and elemental an alyses of these electrodes were examined by means of scanning electron micr oscopy. The electrochemical behaviour was characterized by cyclic voltammet ry (CV) and linear scanning voltammetry (LSV). The effects of electrolyte c onditions on the current efficiency (CE) of hypochlorite production on bina ry (Ru + Pt)O-x electrodes and the treatment of a high salt-containing dye wastewater using this hypochlorite were also investigated. The highest CE f or hypochlorite production occurred on the RP1 (20 mol% Pt in precursor) el ectrode. The major factors influencing CE for hypochlorite production were the electrolyte flow rate, current density and chloride ion (C1(-)) concent ration. The RP1 electrode exhibited the best removal of organics and chromo phoric groups in the dye wastewater. On this electrode, better removal of o rganics and chromophoric groups was obtained at 300 mA cm(-2). The colour o f black-red dye wastewater became light yellow when a charge of 13.2 A h wa s passed while the COD of the wastewater decreased from 10 500 to 1250 mg L -1.