Photodegradation of cresol red by a non-iron Fenton process under UV and sunlight irradiation: Effect of the copper(II)-organic acid complex activated by H2O2

Abstract

The copper(II)-organic acid complex activated by H2O2 was known to be a non-iron Fenton process. In this work, photodegradation of cresol red (CR) by a non-iron Fenton process (Cu(II)-Ox- H2O2) using Cu(II)-Oxalic acid (Ox) complex as catalyst was investigated. The results demonstrate that the combination of light and Cu(II)-Ox complex in situ generates H2O2 by producing reactive oxidants through the reaction of Cu(I) with H2O2. The second part, dedicated to the study of capacity of Cu(II)-Ox- H2O2 system to induce the degradation of CR. Kinetics experiments showed that the external supply of H2O2 to the Cu(II)-Ox system was found to further enhance the effectiveness of CR. Here, we further investigate the synergistic effect in different systems (two-component system UV/Cu(II)-Ox, and three-component system UV/Cu(II)-Ox-H2O2 with CR under the same conditions. Parameters such as pH, the initial concentrations of Cu(II), oxalic acid (Ox) and H2O2 were all investigated. Furthermore, the radical scavenging activity studies indicated that •OH was the dominant active species responsible for CR removal, and O2–• could promote CR degradation in Cu(II)-Ox-H2O2 system. These result strongly confirmed the feasibility of non-iron Fenton process (Cu(II)-Ox- H2O2) under excitation by sunlight.