Kinetics of the Degradation of Tetracycline Hydrochloride by H2O2 in the Presence of Cu–Fe3O4 Nanoparticles Under Sonication

The kinetics of degradation of tetracycline hydrochloride by H₂O₂ in the presence of Cu–Fe₃O₄ nanoparticles were investigated. Copper-doped Fe₃O₄ nanoparticles were synthesized by mixing the required amount of FeCl₂, FeCl₃ and CuSO₄ solutions and then precipitation by adding the 30% NH₄OH solution dropwise. The dried and washed precipitates were characterized by using EDS, XRD, SEM and FTIR techniques. The EDS indicated the presence of Fe, Cu and O, whereas the XRD showed crystalline nanoparticles with average size of 20–25 nm. The FTIR confirmed the presence of Cu–O and Fe–O bonds. The kinetics of degradation of tetracycline hydrochloride (TC) were studied by spectrophotometrically under sonication at 40 °C. The addition of H₂O₂ and nanoparticles to the tetracycline hydrochloride solution resulted in the disappearance in the absorbance intensity of TC with time. The rate constant values were investigated at different concentrations of TC, H₂O₂, HCl, nanoparticles dosage, surfactants, etc. The peak-like curve was obtained for the plot of rate constant values versus the concentrations of H₂O₂, HCl and nanoparticles dosage. The nanoparticles catalyse the reaction by producing the ^·OH radicals on interaction with H₂O₂. These ^·OH radicals oxidize TC and, thus, helps to eliminate the TC molecules from the wastewater. The kinetics studies carried out in the presence of surface-active molecules like sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB), triton X-100 (TX100), polyvinyl alcohol (PVA), etc. demonstrated that the nanoparticle-H₂O₂ is effective in the degradation of TC in the presence of such contaminants.