Photocatalytic degradation of tetracycline hydrochloride by FeNi3/SiO2/CuS magnetic nanocomposite under simulated solar irradiation: Efficiency, stability, kinetic and pathway study

In this study, the FeNi3/SiO2/CuS was initially synthesized and characterized using XRD, FTIR, DRS, BET, EDX, VSM, TEM, FESEM and TGA. Then, its efficacy was investigated in the tetracycline photocatalytic degradation process under simulated solar light. The effect of different parameters such as initial tetracycline concentration, catalyst dose, H2O2 concentration, contact time and pH had also been investigated. The maximum degradation efficiency for the photocatalytic degradation phase and photocatalytic heterogeneous Fenton-like phase was obtained at pH = 9 and pH = 5, respectively. The kinetic model of the photocatalytic degradation processes was pseudo-first-order (R2=0.9). Adding hydrogen peroxide to 200 mL at pH = 5 and 0.005 g/L of nanocomposite resulted in the complete removal of tetracycline used in this study at 200 min. The results of the optical catalyst experiments showed that the newly synthesized nanocomposite in this study had the ability to be recycled. Additionally, the degradation pathway of tetracycline in the photocatalytic heterogeneous Fenton-like process manifested the breakdown of the cyclic compound and the simplification of pollutants into linear compounds and finally turned into water and carbon dioxide. Due to the high efficiency of synthesized nanocatalyst in tetracycline degradation by photocatalytic processes, it can be used as an appropriate catalyst for the degradation of resistant organic pollutants.