influence of operational parameters and kinetic modelling of catalytic wet air oxidation of phenol by al/zr pillared clay catalyst

Single and mixed oxide al/zr-pillared clay (al/zr-pilc) catalysts were synthesized and tested for catalytic wet air oxidation (cwao) of aqueous phenol solution under milder conditions, in a semi-batch reactor. the catalysts were synthesized from natural bentonite clay using ultrasonic treatment during the aging and intercalation steps and were characterized using high resolution scanning electron microscopy-energy dispersive angle x-ray spectrometry (hrsem-edx), powder x-ray diffraction (p-xrd), nitrogen adsorption/desorption, fourier transforms infrared (ft-ir) spectroscopy and zeta potential. successful pillaring of aluminum and zirconium oxides into the clay was confirmed by p-xrd with increased basal spacing (1.92 nm) and higher specific surface area (230 m^2/g). the influence of stirrer speed (200-1000 rpm), catalyst dosage (1-3 g/l), initial ph (1-3), initial phenol concentration (500-1500 mg/l), the effect of temperature (80-150 °c) and oxygen pressure (5-15 bar) was evaluated on phenol conversion and their reaction kinetics. at the optimum conditions of initial ph of 3, catalyst dosage of 2 g/l, initial phenol concentration of 1000 mg/l, reaction temperature of 100 °c and oxygen pressure of 10 bar, the complete removal of phenol was achieved by al/zr-pilc within 120 min. the cwao process was well-described by the first-order power rate law kinetics model. the apparent activation energy of the reaction calculated by arrhenius equation was 21.306 kj/mol.