Kinetics study of catalytic wet oxidation of phenol over novel ceria promoted mesoporous silica supported Ru-Fe3O4 catalyst

Abstract

A novel catalyst was synthesized via excess solution impregnation (ESI) of Ru and Fe3O4 nanoparticles (NPs) on ceria-loaded mesoporous SiO2 and mesoporous SiO2 was synthesized using sol-gel method. Degradation of phenol and effluent containing phenol from resin industry was performed over Ru-Fe3O4/CeOx-SiO2 (Ce3+/Ce4+, x = 1.64) catalyst in an autoclave reactor at 423 K and 14 bar oxygen pressure. Effective phenol degradation of 95% for the model aqueous solution of phenol and 92% for industrial effluent containing phenol were achieved when the both ruthenium and iron loadings were 0.25 wt% under optimized reaction conditions. The close contact between ruthenium and Fe3O4 nanoparticles facilitated the oxidation of phenol at very low temperature, whereas ceria NPs act as a promoter for oxidation reaction. The kinetics insights of oxidation reaction were studied and the catalysts were characterized thoroughly using BET, TPD, XRD, SEM, HR- TEM, ICP-AES, XPS and CO chemisorptions techniques. High surface area and large mesopores of silica facilitated the fine dispersion of the active catalytic sites and oxygen vacancy as supported by the DFT study for catalytic activity. Optimal process conditions could render much higher phenol degradation efficacy in comparison with previous scientific investigations.