Multiple reinforcement of chloride ion on oxidizing acetaminophen with zero-valent copper particles: In-site formation and catalysis of hydrogen peroxide

Zero-valent copper particles (Cu 0 ) used to degrade pollutant due to its in-site generation and activation of hydrogen peroxide (H 2 O 2 ), while the disproportionation of Cu + limited the efficacy. In this study, spiking chloride ion (Cl − ) into zero-valent copper (Cu 0 ) system (Cl − /Cu 0 system) enhanced greatly acetaminophen degradation. The addition of Cl − not only reduced the dismutation reaction of Cu + , but also helped the comproportionation reaction of Cu 0 and Cu 2+ , leading to much generation of Cu + and H 2 O 2 . Hydroxyl radical ( OH) and reactive chlorine species were identified as the dominant reactive oxidants in the Cl − /Cu 0 system with its contribution ratio of degrading acetaminophen being respectively 73.4 % and 23.8 %. In the Cl − /Cu 0 system, Cu + was released by H + corrosion from Cu 0 , and then Cu + coupled with Cl − forming Cu-Cl complexes; Meanwhile, the reaction of O 2 and the species of Cu + (e. g. Cu-Cl complexes and Cu + ) produced H 2 O 2 and, then the species of Cu + catalyzed H 2 O 2 to form OH; Thereinto, partial OH was shifted by Cl − to reactive chlorine species. Except for fulvic acid , coexisting substrates such as sulphate, nitrate and phosphate ions had no obvious inhibition impact on oxidizing acetaminophen in the Cl − /Cu 0 system. Furthermore, the Cl − /Cu 0 system presented a good removal rate of acetaminophen in three actual water samples. Moreover, three kinds of dyes and painkillers was removed over 78 % in the Cl − /Cu 0 system. The residual total dissolved copper was under II-level of environmental quality standards for surface water in China by alkali precipitation and filtration after reaction. Therefore, the study provided a new idea to enhance Cu 0 for the purification of pollutants.