Fenton-like degradation of methyl orange by alumina-supported Cu–Co catalysts at neutral pH: Optimization by the Taguchi method

Abstract

Fenton oxidation is considered to be an effective method for removing non-biodegradable organic materials from industrial wastewater. However, several challenges need to be overcome for its utilization in industrial-scale applications. A series of alumina-supported Cu–Co samples were prepared via a simple sol–gel method, and their utility for Fenton-like degradation of methyl orange (MO) at neutral pH was assessed. In addition, various catalyst synthesis parameters, namely (Cu + Co)/Al molar ratio, Cu/Co molar ratio, water content, and treatment conditions, were optimized by the Taguchi method. The parameters were selected in three levels, and L9 from the orthogonal array design was used. The optimum synthesis parameters for the catalyst included a (Co + Cu)/Al molar ratio of 0.08, a Co/Cu molar ratio of 1/3, an H2O/Al molar ratio of 6, a calcination temperature of 400°C, and a calcination time of 8 h. Furthermore, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed reduction were employed to characterize the physical and chemical properties of the samples. The results revealed that the optimized catalyst achieved a 94% removal efficiency of MO and a 75% removal efficiency of total organic carbon. Compared to the data reported in similar previous studies, the catalyst prepared herein demonstrated promising development potential.