Preparation of CuO/HZSM-5 catalyst based on fly ash and its catalytic wet air oxidation of phenol, quinoline and indole

Abstract

Abstract This work aims to use fly ash and the organic template of tetrapropyl ammonium bromide (TPABr) to synthesize the catalyst carrier of HZSM-5 and prepare the catalyst of CuO/HZSM-5 for catalytic wet air oxidation (CWAO) of phenol, quinoline and indole in aqueous solution. The carrier and the catalyst were characterized by x-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and Brunauer-Emmett-Teller (BET) tests and the results indicate HZSM-5 zeolite and CuO/HZSM-5 catalyst have been successfully synthesized. The specific surface area of catalysts with copper loading from 0 to 15% decreased from 310.1 m2 g−1 to 253.8 m2 g−1. The results of catalyst performance showed that the catalyst of CuO/HZSM-5 with copper loading of 10% has the best removal effect on the mixed aqueous solution containing phenol, quinoline and indole. When the total concentrations of phenol, quinoline and indole are 200 mg.l−1 (namely 120 mg phenol·l−1, 60 mg quinoline·l−1 and 20 mg indole·l−1), the catalyst with the copper loading of 10% can remove these organic matters with 100% efficiency after reaction for 4 h at 200 °C and the COD removal rate is more than 75%. Under the same experimental conditions, if the reaction temperature drops to 120 °C, the COD removal rate will rise to 86.2%. The CWAO experiments showed the optimum reaction temperature range for the Cu-10% catalyst is from 120 °C to 150 °C.