Degradation of azo dye by an UV/H2O2 advanced oxidation process using an amalgam lamp

Abstract

AbstractThe discharge of dyes into water is an ecological problem that can be alleviated by advanced oxidation processes (AOPs), such as UV/H2O2 treatments. Searching for more efficient light sources is a way to improve AOPs’ efficiency. This work tested the efficiency of an amalgam lamp on the degradation of an azo dye, studying the effect of dye and H2O2 concentrations and pH, and the influence of some salts on the decolouration rate of methyl orange. Actinometry showed that the amalgam lamp system was able to provide a high incident photon irradiance (6.30·10−5 mol/cm2 s). The amalgam lamp‐driven AOP was able to decolourize the dye at pseudo‐first‐order rates of 0.654–4.008 1/min, with increasing rates at low dye concentration and low pH and at high H2O2 concentrations until a maximum value is reached. The results show that the amalgam lamp can be an alternative light source for fast dye degradation by AOPs.