Effect of copper ion-exchange on catalytic wet peroxide oxidation of phenol over ZSM-5 membrane

Abstract

Cu-ZSM-5 zeolite membrane catalysts prepared by ion exchange method were synthesized on paper-like sintered stainless fibers (PSSFs) with three-dimensional net structure for the catalytic wet peroxide oxidation (CWPO) of phenol in structured fixed bed reactor. The experimental results exhibited that the BET of optimal catalyst was 165 m2/g with the ion exchange concentration of 0.1 M and time of 24 h, respectively, at temperature of 40 °C and one time ion exchange. The FT-IR results illustrated that band intensity was the lowest, and original Cu+ species and lattice oxygen were predominant in optimal catalyst according to the XPS results. Then, the effects of ion exchange concentration, time, temperature and times on catalytic performance of phenol were also investigated in structured fixed bed. It was found that the phenol was completely removed, TOC conversion (around 76.6%), high CO2 selectivity (about 78%) and low copper leaching rate (about 30%) were achieved with only 1.91 wt% copper loading over the optimal catalyst. Finally, a reasonable reaction mechanism occurring in the presence of H2O2 for CWPO of phenol was proposed by analyzing the HPLC results, which indicated Fenton-like reactions were mainly based on the HO· production by catalytic decomposition of hydrogen peroxide with Cu+ species.