Photodegradation of Erythromycin antibiotic by γ-Fe2O3/SiO2 nanocomposite: Response surface methodology modeling and optimization

Efficient adsorbent γ-Fe2O3/SiO2 nanocomposites were synthesized using sol-gel method. The developed adsorbent was well characterized using various analytical techniques such as XRD, TEM, SEM, BET and DRS techniques. The obtained XRD pattern that revealed a strong Si (111) peak at 28.1°. On the other hand, the patterns of display representative γ-Fe2O3 peaks were centered at 2θ = 31.2°, 33.9°, 44.1°, 52.5°, 57.6°, and 63.9°, due to (220), (311), (400), (422), (511), and (440) planes, respectively. The DRS analysis of γ-Fe2O3/SiO2 nanocomposite that shifted to a lower wavelength (blue-shift), reveals the high photocatalytic activity of the developed adsorbent. The central composite design superimposed with the response surface methodology (RSM) was used for the optimization of the influential parameters and photocatalytic removal of Erythromycin antibiotic. The obtained optimized values for the rapid removal of Erythromycin antibiotic were as follows: γ-Fe2O3/SiO2 nanocomposite dosage of 500 mg L- 1, initial RhB concentration of 6 mg L- 1, the irradiation time of 6 min, and pH = 8.