FeNi3/SiO2 magnetic nanocomposite as an efficient and recyclable heterogeneous fenton-like catalyst for the oxidation of metronidazole in neutral environments: Adsorption and degradation studies

In present research, firstly, FeNi3/SiO2 magnetic Nano composite was synthesized and then used in the presence of H2O2 as a heterogeneous Fenton-like catalytic process for removing the antibiotic metronidazole. The morphology and the other properties of the synthesized nanocomposite were characterized by XRD, FESEM, TEM, FTIR and VSM techniques. The present study was conducted in batches (with pH values of 3, 5, 7, 9, and 11), in nanocomposite doses (ranging 0.005-0.1 g/L), in metronidazole concentrations of 10-30 mg/L, and a hydrogen peroxide concentration range of 50-200 mg/L. The results were read by the device (Spectrophotometer UV/Vis T80(+)) and showed that by increasing the dose of Nano catalyst synthesized from 0.005 to 0.1 g/L, the percentage of pollutant removal increased from 40.96 to 80.29% in 180 min. Also with increase of the concentration of metronidazole from 10 to 30 mg/L the percentage of deletion decreased markedly (95.32-63.14%). with the elevation of H2O2 concentration from 50 to 150 mg/L, the percentage of metronidazole degradation increased from 64.73% to 80.29%. This issue can be attributed to the point that with the elevation of H2O2 concentration from 50 to 150 mg/L, the concentration of hydroxyl radicals increased as did the metronidazole removal percentage. Owing to hydroxyl radical scavenging and the recombination of the hydroxyl radical, however, with the elevation of H2O2 concentration to 200 mg/L, the removal percentage dropped to 03/75%. Furthermore, the kinetics of the degradation rate of metronidazole followed the pseudo-first-order equation (R-2 > 0.9) and the constant rate of degradation of this reaction was obtained as 0.0044 1/min. In this study, the efficiency and the reusability of the synthesized magnetic nanocomposite were examined in the removal of metronidazole. The findings suggest that after 6 cycles of performance of this Nano catalyst, had no significant decrease so that the removal efficiency from the first cycle to the last cycle showed a decrease of about 7.99%. The present research showed that the heterogeneous Fenton-like catalytic process of FeNi3/SiO2/H2O2 had very good efficiency in removing metronidazole antibiotic contamination from aqueous solutions.