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.