Photocatalytic Degradation of Ethylbenzene in Aqueous Solutions by ZnFe2O4 Nanoparticles Supported on the Copper Slag: Optimization, Kinetics and Thermodynamics Studies

ZnFe2O4/copper slag (CS), an environmentally friendly and cost-effective catalyst, was produced by co-precipitation methods and a thermal process. The synthesized catalyst was characterized by XRD, SEM, EDX and BET surface area analyses. The X-rays diffraction pattern confirmed that the crystal structure of ZnFe2O4 after stabilization on CS zeolite has not changed. The SEM images showed that despite their varying sizes, the particles all have the same shape. Photocatalytic activity of the catalyst was tested for the degradation of ethylbenzene (EB) in water by UV + H2O2 method in a reverse-flow packed bed photo reactor. The process optimization and modeling were performed using the full factorial method. The best conditions were found to be 30 ppm the initial EB concentration, pH = 9, and 15 ppm the initial H2O2 concentration. Under ideal process conditions, the removal efficiency of EB was greater than 99.5%. The validity of the Langmuir-Hinshelwood kinetics model was confirmed using EB photocatalytic degradation experimental results. The values of ΔH# and ΔS# for the photocatalytic degradation of EB by ZnFe2O4/CS catalyst in the UV + H2O2 process were calculated based on the transition state theory and gave 1.67 kJ mol^-1 and -263.057 J K^-1 mol^-1, respectively.