Synergistic photocatalytic degradation of ciprofloxacin under natural sunlight using hot dip galvanization and medical incineration waste residues

Abstract

To improve the photodegradation capacity, for the first time, a simple yet efficient photocatalyst was prepared by solely employing hot dip galvanization waste (GW) and fly ash (FA) disposed from medical waste incinerators. Impressively, the as-synthesized photocatalyst (GW-FA) in the ratio 3:1 displayed an outstanding ciprofloxacin degradation efficiency of 98.3% under natural sunlight within 60 min and possessed superior reusability. Herein, adjusting the amount of GW evidenced effective tuning of the electronic band structure and increased active sites. Detailed microscopic morphology, chemical structure, magnetic, and optical properties of GW-FA were studied by UV-DRS, FESEM-EDX, HRTEM, XRD, XPS, ESR, VSM, and AFM, which confirmed the successful fabrication of GW-FA and their outstanding ability to reduce the recombination rate. Besides, the effects of crucial experimental parameters (concentration, pH, and photocatalyst loading) on ciprofloxacin degradation were examined using RSM-BBD. Further, OH• was manifested to be the main active species for the photodegradation of ciprofloxacin. Eventually, GC-MS analysis was employed to deduce plausible photodegradation pathways, and ICP-AES analysis proved that the concentration of leached heavy metals was lower than that of the standard limits for irrigation water. This work establishes a new route for effectively reutilizing waste generated from medical waste incinerators and galvanization industries as a photocatalyst, which otherwise would be disposed in landfills.