Chemical vapor deposition of CuO on ZSM-5 membrane for catalytic wet peroxide oxidation of phenol in a fixed bed reactor

Abstract

CuO over ZSM-5 zeolite membrane was prepared by chemical vapor deposition (CVD) for catalytic wet peroxide oxidation (CWPO) of phenol in a fixed bed reactor. Firstly, Cu-ZSM-5/PSSFs catalysts with Cu loading of 2 wt%, 4 wt% and 6 wt% were prepared and characterized by XRD, XPS, SEM, EDS, N₂ adsorption–desorption and TPR (H₂), respectively. Compared with CuO deposited directly onto PSSFs, the CuO supported on ZSM-5/PSSFs tended to be more regular with smaller crystal size. Then, several parameters affecting H₂O₂ consumption and phenol oxidation such as reaction temperature, Cu loading, and different supports were investigated in the CWPO of phenol with a high concentration (1 g L⁻¹ phenol and 5.1 g L⁻¹ H₂O₂). Experimental results revealed that Cu-ZSM-5/PSSFs (6%) showed better activity for the oxidation of phenol than Cu-ZSM-5/PSSFs catalysts with lower Cu loading and CuO/PSSFs with same theoretical loading. A complete reduction of phenol and a high TOC removal around 60% had been achieved over Cu-ZSM-5/PSSFs (6%) at the temperature of 80 °C, feed flow rate of 2 mL min⁻¹ and catalyst bed height of 2 cm. Finally, the possible oxidation pathway of phenol was studied based on the by-products detected by high-performance liquid chromatography (HPLC).