ELECTROCHEMICAL OXIDATION OF 4-NITROPHENOL BEARING WASTEWATER

Abstract

The electrochemical oxidation is an effective treatment technology for wastewater treatment. In this method, use of the electrical energy can produce complete oxidation of pollutants on high oxidation potential. In present study, oxide coated metal electrode (Ti/RuO2) was used for the electrochemical oxidation of 4-nitrophenol treatment on laboratory scale under the different experiment condition of current density (j=56.3 to 225.2 A/m2), initial pH (pHo=3-9) and initial electrolyte (NaCl) concentration (m=150 to 500 mg/L) and initial concentration of 4-nitrophenol (Co=50-500 mg/L) within 150 min of treatment. The removal efficiency was determined in terms of chemical oxygen demand (COD) and total organic carbon (TOC). 4-NP was oxidized by both direct (hydroxyl radical generated water electrolysis on anode surface) and indirect (via mediators, hypochlorous acid and active chlorine generated chlorine oxidation in solution) EC oxidation. Various powerful oxidizing species generated during direct and indirect oxidation were capable of rapidly oxidizing 4-NP. Maximum removal COD and TOC efficiencies were found to be 98.87% and 81.92%, respectively, at j=168.9 A/m2, pHo=6, Co=100 mg/L and m=300 mg