Enhanced visible-light-responsive photodegradation of ciprofloxacin by direct Z-scheme ZnFe2O4@g-C3N4 nanocomposites

The zinc ferrite@graphitic carbon nitride (ZnFe2O4@g-C3N4, ZFO@CN) nanocomposites were fabricated as the direct Z-scheme heterostructured photocatalysts for the enhanced visible-light-driven photodegradation of ciprofloxacin (CIP). The 15 - 30 nm ZFO, fabricated from the nonaqueous hydrothermal method, is well-distributed on the sheet-like CN structure, resulting in the high specific surface and mesoporosity with increased surface-tovolume ratio and reactive sites. Moreover, the heterojunction interface between ZFO and CN enhances the visible light response as well as decreases the electron-hole recombination, and subsequently increases the photodegradation performance of CIP over ZFO@CN. A nearly complete removal efficiency with a rate constant of 0.047 min(-1) for CIP photodegradation is observed. The environmental parameters including pH, initial CIP concentration, inorganic anions and water matrices were examined to optimize the photocatalytic activity of the ZFO@CN nanocomposite. The ZFO@CN nanocomposite exhibits excellent structural and physicochemical stability and good reusability over 5 cycles. The radical trapping results signify that .O-2(-) and h(+) are the primarily responsible radicals for the enhanced degradation of CIP over direct Z-scheme ZFO@CN heterojunction. Results clearly elaborate on the superiority of ZFO@CN over the photodegradation of CIP, which can serve as the platform for the fabrication of metal oxide@CN as the Z-scheme heterojunction for water and wastewater purification.

Automated summary

The zinc ferrite@graphitic carbon nitride (ZnFe2O4@g-C3N4, ZFO@CN) nanocomposites were fabricated to enhance the visible-light-driven photodegradation of ciprofloxacin (CIP). The heterojunction interface between ZFO and CN increases the photodegradation performance of CIP. The ZFO@CN nanocomposite shows excellent stability and reusability for water and wastewater purification.