Visible-light-driven TiO2@Fe2O3/Chitosan nanocomposite with promoted photodegradation of meropenem and imipenem antibiotics by peroxymonosulfate

Abstract

This study assessed wastewater treatment by visible-light/Peroxymonosulfate process using its linking with TiO₂@Fe₃O₄ nanoparticles coated on chitosan. Meropenem and Imipenem photodegradation was evaluated as a model-resistant contaminant by TiO₂@Fe₂O₃/chitosan nanocomposite. The synthesised TiO₂@Fe₂O₃/chitosan was characterised using various techniques. Fe₂O₃ and TiO₂ nanoparticles on the chitosan surface were affirmed via XRD, EDX, and FTIR findings. The FESEM and TEM results verified the deposition of TiO₂@Fe₂O₃ on the chitosan surface. Under optimum circumstances (pH = 4, catalyst dosage = 0.5 g/L, antibiotics concentration = 25 mg/L reaction time = 30 min, and PMS = 2 mM), maximum degradation efficiency was obtained at about 95.64 and 93.9% for Meropenem and Imipenem, respectively. Also, the experiments demonstrated that TiO₂@Fe₂O₃/chitosan had a better performance than photolysis and adsorption by catalyst without visible light irradiation in degrading antibiotics. The scavenger tests confirmed that $O_2^{\cdot -}$, ${\mathrm{SO}}_4^{\cdot -}$, $\mathrm{HO}\cdot$, and h⁺ are present simultaneously during the pollutant photodegradation process. After five recovery cycles, the system eliminated over 80 percent of antibiotics. It suggested that the catalyst's capacity to be reused may be cost-effective.

Keywords: TiO2-based catalyst; antibiotic; chitosan; hospital wastewater; photocatalytic process.