The Contribution Of CuO To Catechol Degradation And The Reaction Mechanism Under Ultraviolet-Visible Irradiation

Environmentally persistent free radicals (EPFRs) have caused some environmental and medical researcher’s concern in recent years, due to its longer environmental life, stronger stability in environment and a potential damage to DNA and cardiopulmonary system. On the surface of the particles, the electron transfer and metal reduction interactions occur in the coexist of substituted aromatic compounds (such as phenol and chlorophenol) and transition metals, followed by EPFRs produce. In addition, EPFRs can be generated in air particulate matters and soil, even in the process of pyrolysis and combustion.In most of research systems, the researchers focus on the formation process and potential risk of EPFRs, but the research on the EPFRs environmental behavior is very absent. And the discovery of EPFRs has raised a challenge to the traditional method of assessing the risk of pollutants with concentration. Most studies on CT and CuO have focused on the photocatalytic degradation/photo Fenton degradation, which have no correlation with the possible EPFRs and its effects. Therefore, it is very important to understand the impact of EPFRs on the environmental behavior of pollutants and the generation of new pollutants.Under UV irradiation condition, in N2 and air two gas atmosphere, the formation mechanism and characteristics of EPFRs and its influence on catechol (CT) degradation is mainly investigated in this research, when organic pollutants CT and transition metal Cu coexist. Study found that under UV irradiation condition, compared to CT-SiO2 particles, more stable EPFRs were observed during the interaction and electron transfer between CT and transition metal on the surface of 1% CuO/SiO2 particles, both in N2 and air two gas atmosphere.In N2 atmosphere, the signal intensity of EPFRs is greater than that of Air, while the g factor is less than Air. These EPFRs are mainly semiquinone radicals with a g factor of 2.0045-2.0052, and its environmental life vary from 14 h to 3 d. In addition to health risks, the generation of EPFRs decreased CT degradation in the lower concentration, and thus altered CT environmental behavior and increased its environmental risks, objectively needing to consider EPFRs contribution in the environmental fate of organic pollutants.