Synthesis of N-doped TiO₂/SiO₂/Fe₃O₄ magnetic nanocomposites as a novel purple LED illumination-driven photocatalyst for photocatalytic and photoelectrocatalytic degradation of naproxen: optimization and different scavenger agents study

Abstract

N-doped TiO₂/SiO₂/Fe₃O₄ as a new magnetic photocatalyst that is active in visible light has been prepared by simple sol–gel method. The prepared samples were characterized by XRD, FESEM, EDX, TEM, BET, BJH, VSM, XPS, FT-IR, and DRS–UV/Vis analysis. The photocatalytic effect of synthesized samples on naproxen degradation was studied. The operational parameters were optimized through central composite design to achieve maximum efficiency. The optimum values for maximum efficiency were obtained at pH of 4.29, catalyst mass of 0.06 g, naproxen concentration of 9.33 mg L⁻¹, and irradiation time of 217.06 min. At these optimum conditions, the maximum photocatalytic degradation percentages of naproxen were found to be 96.32% at desirability function value of 1.0. Coupling the electrical current with the photocatalytic process proved that the electrical current was considerably efficient in decreasing the degradation time of removing the naproxen from aqueous solutions. The photocatalytic activity of the nanoparticles was also studied under sunlight. Considering the results provided by UV–Vis spectrophotometry and total organic carbon, it was found that the prepared samples are extraordinarily efficient to degrade naproxen under both purple LED and solar lights. Furthermore, the effect of different scavenger agents on naproxen degradation has been studied.

Keywords:

• Photodegradation
• pharmaceutical compound
• core–shell nanocomposite
• titanium dioxide
• experimental design

Acknowledgments

Laboratory Complex of Islamic Azad University Science and Research Branch in Tehran is gratefully acknowledged for providing educational and research services.