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).