Catalytic peroxidation of acrylonitrile aqueous solution by Ni-doped CeO2 catalysts: characterization, kinetics and thermodynamics

Acrylonitrile is one of the major pollutants of acrylonitrile-butadiene-styrene resin industry wastewater present in high concentration. In the current study, the treatment of acrylonitrile from aqueous solution was performed by catalytic peroxidation using Ni-doped CeO2 catalysts. Various catalysts with different loadings of nickel were synthesized by co-precipitation method and further characterized by X-ray diffraction, Fourier transform infrared spectroscopy, liquid nitrogen adsorption-desorption technique, transmission electron microscopy, scanning electron microscopy with energy-dispersive X-ray, thermogravimetric analysis and X-ray photoelectron spectroscopy. The effects of various parameters such as catalyst dose, pH, nickel loading, H2O2/acrylonitrile molar ratio, initial concentration of acrylonitrile, temperature and reaction time on acrylonitrile removal were studied. Maximum acrylonitrile removal of 84.12% was observed at optimum operating conditions of pH = 6.5, catalyst dosage = 500 mg/L, nickel loading = 2.5 wt.%, stoichiometric molar ratio (H2O2/acrylonitrile) = 1, temperature = 298 K and reaction time = 3 h. Acrylonitrile degradation kinetics was investigated using power law model and non-competitive Langmuir-Hinshelwood model in which non-competitive Langmuir-Hinshelwood isotherm model better fitted for acrylonitrile degradation using Ni-doped CeO2 catalyst. Thermodynamic study of the parameters has also been presented.