Ultrasonic-assisted synthesis of α-Fe2O3@TiO2 photocatalyst: Optimization of effective factors in the fabrication of photocatalyst and removal of non-biodegradable cefixime via response surface methodology-central composite design

Abstract

Environmental pollution becomes a major worldwide issue that threatens the entire biosphere.On the other hand, visible-light photocatalysis technology is one of the most effective approaches to wastewater treatment due to its superb removal efficiency, facile process, and ecological friendliness.Herein, a highly efficient α-Fe2O3@TiO2 nanocomposite was synthesized using a rapid sonochemical technique and a conventional wet impregnation route for the elimination of cefixime. Towards achieve the optimal photocatalyst, the influences of operational parameters including calcination temperature (300–600 °C), and Fe2O3 loadings (1-5 wt%) were examined utilizing the Response Surface Methodology (RSM). Additionally, two important factors, irradiation time (3–8 min) and power (50–90 W) of ultrasonic waves, were investigated to optimize the efficiency, dimension, and structure of the photocatalyst. Then, the manufactured nanocomposites were characterized with the aid of techniques TEM, XRD, BET, FE-SEM, EDS-map, FTIR, and UV–Vis band gap analysis. The optimal photocatalyst (3.09 wt%, 439.34 °C, 70 W, and 8 min) was used to study the effect of four efficacious variables on cefixime removal by RSM. Maximum cefixime degradation (98.8%) occurred at optimum conditions (cefixime concentration = 20.5 mg/L, pH = 4.76, Irradiation time = 103 min and catalyst dose = 0.012 g/l). Based on the empirical data, statistical analysis proved the regression model's validity and adequacy. The COD elimination revealed that in comparison with other studies the α-Fe2O3@TiO2 photocatalyst could successfully mineralize cefixime (82.4%). Generally, the stability of α-Fe2O3@TiO2 in the photocatalytic degradation of cefixime was observed across five cycles with minimal iron leaching, making it a perfect catalyst for the removal of non-biodegradable pharmaceuticals.