Three-Dimensional Electrochemical Oxidation System with RuO 2 -IrO 2 /Ti as the Anode for Ammonia Wastewater Treatment

In this study, a three-dimensional electrochemical oxidation system was constructed to treat ammonia nitrogen wastewater generated from the tail gas absorption of a methionine producer by using a homemade MAC mixed with a GAC at a mass ratio of 1:2 as the particle electrode, with a RuO 2 -IrO 2 /Ti polar plate as the anode and a stainless steel plate as the cathode. The effects of current density, initial pH value of wastewater, plate spacing, NaCl concentration and particle filling amount on COD Cr and NH 4 + -N removal were investigated through single-factor experiments, and the removal pathways of COD Cr and NH 4 + -N under the system were initially explored via cyclic voltammetry curves, scanning electron microscopy and tertiary butanol quenching experiments. The experimental results showed that the average removal rate of COD Cr was 91.03% and that of NH 4 + -N was 98.89% after electrolysis for 5 h under the conditions of a current density of 40 mA/cm 2 , no pH adjustment, the spacing of the electrode plates of 8 cm, the NaCl dosing concentration of 1 g/L, and the particle filling amount of 400 g/L. Under this experimental condition, the removal of COD Cr occurred mainly through the indirect oxidation of active chlorine and ·OH, and the removal of NH 4 + -N mainly through the indirect oxidation of active chlorine.