Rapid oxidation of acetaminophen with zero-valent copper induced hydrogen peroxide process in presence of ferric ion and chloride ion

Abstract

Zero-valent copper-triggered hydrogen peroxide (Cu0/H2O2) process was widely used for the degradation of pollutants, while its oxidation efficacy was restrained by the interaction of Cu+ with O2 as well as the dismutation of Cu+. In this study, both ferric ion (Fe3+) and chloride ion (Cl−) were introduced into the Cu0/H2O2 (Fe3+/Cl−/Cu0/H2O2) system, and the removal of acetaminophen was immensely enhanced. In the Fe3+/Cl−/Cu0/H2O2, Fe3+ was converted to Fe2+ via the reaction of Fe3+ with Cu0 and Cu+, and the reaction between Cu+ and Fe3+ receded the reaction of Cu+ with O2, promoting the formation of reactive oxygen species; Cl− integrated with Cu+ to form the Cu-Cl chelate, and Cl− helped the comproportionation of Cu0 and Cu2+ to form CuCl, which decreased the reaction of Cu+ with O2 and promoted the generation of reactive oxygen species. Both the addition of Fe3+ and Cl− in the Cu0/H2O2 process greatly improved the utilization of Cu0. •OH, Various reactive oxygen species such as •OH, FeIVO2+ and reactive chlorine species were identified in the Fe3+/Cl−/Cu0/H2O2 process. There into, Fe2+ stimulated H2O2 to form •OH and FeIVO2+, and Cu+ triggered H2O2 to form •OH rather than Cu3+, and partial •OH was transferred to reactive chlorine species via the interaction of •OH with Cl−. After increasing the solution pH to > 7.0 and leaching solution, the total copper of reaction solution was below 0.455 mg/L. These results suggested that the Fe3+/Cl−/Cu0/H2O2 process was feasible, effective and environmentally safe, and the research offered a theory instruction for the application of Fe3+ and Cl−-enhanced Cu0/H2O2 process in pollutants decomposition.