Catalytic oxidation of SO2 by novel Mn/copper slag nanocatalyst and optimization by Box‑Behnken design

In this research, the oxidation of sulfur dioxide ( SO2) gases is investigated by Mn/copper slag nanocatalyst (Mn/CS) as a novel catalyst at low temperatures. The removal of SO2 gas from industrial exhaust is important to reduce environmental pollution. The SO2 gas in aqueous solution was oxidized and converted to sulfuric acid as an energy source by Mn/CS in the semi-batch reactor (SBR). The characterization of the catalyst was studied using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR), simultaneous thermal analysis (thermogravimetry/differential thermal analysis) STA (TG/DTA) techniques, X-ray fluorescence microscopy (XRF) and BET surface area. A Box-Behnken design (BBD) was used for the optimization of influencing factors such as the amount of nanocatalyst, the temperature and the reaction time in the oxidation of SO2. The graphical counter plots and response surface were used to determine the optimum conditions. The results showed that the nanocatalyst had the most significant effect on SO2 oxidation compared with the other two variables. Temperature = 283 K, Mn/CS amount = 6 g/L and Time = 60 min were determined as maximum efficiency for oxidation of SO2.