ELECTROCHEMICAL OZONE GENERATION FOR PALM OIL MILL WASTEWATER TREATMENT USING NICKEL/ANTIMONY DOPED TIN OXIDE ANODES

Abstract

Ozonation have been employed in organic matter degradation and discoloration process of wastewater. In this study, nickel-antimony doped tin oxide (NATO) anode was employed to generate ozone for palm oil mill effluent (POME) wastewater treatment. NATO was synthesized varying Ni concentrations and calcination temperatures. The materials were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) techniques. All materials showed rutile structure. The electrode displayed a smooth cracked mud surface morphology. Regarding the oxidation state, the binding energies of the Sb 3d3/2 peak were observed at 540.62 eV and 541.51 eV corresponding to Sb3+ and Sb5+, respectively. The key findings show that increasing calcination temperature increases ozone current efficiency obtained from the absorbances of dissolved ozone in liquid phase and current density, which decreases with increasing Ni content. The highest current efficiency and current density (i.e. ca. 30% and 0.18 Acm-2 in 1 M H2SO4 at 2.7V) was achieved at 2%mole ratio Ni content calcined at 650°C. Regarding POME treatment, discoloration and degradation efficiency increased with electrolysis time from the initial chemical oxygen demand (COD) and total organic carbon (TOC) of 1,780 and 96 mgL-1, respectively under the aforementioned conditions. The highest removal efficiency of 80% was achieved within 10 min discoloration and 15 min for TOC and COD. The electrochemical ozone generation using NATO anode have shown high efficiency in the POME treatment due to •OH radicals and O3. NATO is a promising electrocatalyst candidate for wastewater treatment.