Synthesis and characterization of carbon xerogel based iron catalyst for use in wet air oxidation of aqueous solution containing 2, 4, 6–trichlorophenol

Abstract

Carbon xerogels were prepared using tannic acid, resorcinol and formaldehyde as precursors. The water content of the wet organic xerogels was replaced with t-butanol as a solvent to prevent pore collapse during ambient drying and the carbon xerogels were modified using o-phosphoric acid to improve its surface and textural properties. The xerogels and the carbon xerogel based iron catalyst were characterized for surface, textural and physico-chemical properties using various techniques. The catalytic wet air oxidation (CWAO) of aqueous solution containing 2, 4, 6-trichlorophenol (TCP) was performed using modified carbon xerogel based iron catalyst and the results were interpreted in terms of TCP and chemical oxygen demand (COD) removal efficiencies. The effect of various operating parameters on the TCP and COD removal efficiencies was studied and the maximum TCP and COD removal efficiencies of 74.49% and 24.31%, respectively were obtained at the optimum value of operating parameters. The kinetics of the degradation of TCP was studied. The reusability of the catalyst was explored by repeating CWAO experiments three times with washing and thermal treatment of used catalyst after each cycle. The leaching of iron metal from the catalyst was studied by determining the iron metal content in the CWAO effluent.