Catalytic wet air oxidation of aqueous solution of phenol in a fixed bed reactor over Ru catalysts supported on ceria promoted MCM-41

Abstract

Catalytic wet air oxidation (CWAO) of phenol was carried out in a fixed bed reactor over a noble metal (Ru) supported on silica MCM-41 material. The addition of small amounts of ceria as a promoter to the MCM-41 material enhanced both the activity and selectivity of Ru in this reaction, with significant conversions of about 99% obtained at 413 K and 18 bar oxygen pressure. The oxidation of phenol required moderate temperature and oxygen pressure, and the oxidizing capacity of the catalyst required adjustment. The activation energy of the oxidation reaction was found to be 33 kJ mol⁻¹ at 413 K using the ceria promoted Ru/MCM-41 catalyst. The supports and catalysts were characterized using the Brunauer–Emmett–Teller (BET) surface area, temperature programmed reduction (TPR), CO chemisorption, temperature programmed desorption (TPD), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and inductively coupled plasma atomic emission spectroscopy (ICP-AES).