Zn-CNTs-Cu catalytic in-situ generation of H2O2 for efficient catalytic wet peroxide oxidation of high-concentration 4-chlorophenol

Abstract

4-chlorophenol (4-CP) with high concentration is difficult to degrade thoroughly by traditional treatment methods due to its high biotoxicity and refractory to bio-degradation. A novel catalytic wet peroxide oxidation (CWPO) system based on Zn-CNTs-Cu catalysts through the in-situ generation of H2O2 was constructed and investigated for the degradation of high-concentration 4-CP for the first time. Zn-CNTs-Cu composite was prepared by the infiltration melting-chemical replacement method. The operational factors effect, mechanism, and pathways of Zn-CNTs-Cu/O2 system for high concentration of 4-CP degradation were systematically performed and discussed. At the optimal experimental conditions, the degradation efficiency of 4-CP through CWPO system with Zn-CNTs-Cu/O2 achieved 100 %, which was 689 % higher than that of wet oxidation system with O2 alone. According to the mainly in-situ generated H2O2, the strong oxidative OH radical and wet-oxidation effect of O2, high concentration of 4-CP degraded into small molecular organic matter, even been mineralized into carbon dioxide and water in the Zn-CNTs-Cu/O2 based CWPO system. Overall, Zn-CNTs-Cu/O2 CWPO system can efficiently degrade high-concentration 4-CP through the in-situ generation of H2O2 without extra replenishment, and it provides a novel method and strategy to the efficient treatment of refractory chlorophenols wastewater.