Removal of Cefixime Using Heterogeneous Fenton Catalysts: Alginate/Magnetite Hydroxyapatite Nanocomposite

In this study, alginate, magnetite, and hydroxyapatite were used to fabricate alginate-hydroxyapatite (Alg-Hap), alginate-Fe3O4 (Alg-Fe3O4), and alginate-magnetic hydroxyapatite (Alg-mHap) using ferric chloride (III) crosslinker to remove cefixime from an aqueous solution. FTIR, SEM, VSM, BET, and XRD tests were used to determine the functional groups, morphology, magnetization behavior, surface area, and crystallinity of catalysts, respectively. The optimal pH for the Fenton reaction was determined to be 3.3 for Alg-Hap and Alg-Fe3O4 catalysts and 4 for Alg-mHap catalysts. Increases in the concentration of hydrogen peroxide (1 to 3 mM) and the amount of catalyst (50 to 90 gr/L) increased the percentage of degradation to approximately 8% and 6%, respectively. The degradation efficiency of cefixime by using Alg-mHap as the best catalyst in the Fenton process was achieved 91%, at optimum condition (pH of 4, catalyst amount of 90 gr/L, initial cefixime concentration of 5 mg/L, H2O2 concentration of 3 mM within 90 min). Moreover, the second-order kinetic equation fits the experimental data for cefixime degradation for all three catalysts. Furthermore, not only did the catalysts display a negligible iron leaching (0.92 mg/L for Alg-mHap) but also after three consecutive cycles, the catalysts indicated long-term stability. Comparison between synthesized catalysts and other methods proved its effectiveness.