Microwave-Assisted Development of Magnetically Recyclable PANI-Modified CoFe2O4-WO3 p–n–n Heterojunction: A Visible-Light-Driven Photocatalyst for Antibiotic Toxicity Reduction

Abstract

In view of water toxicity proliferated by the ubiquitous use of antibiotics, there is a desperate need for sustainable materials and methodologies for their toxicity reduction in aqueous media. Herein, we report a novel and noncytotoxic polyaniline (PANI)-modified CoFe2O4–WO3 ternary p–n–n heterojunction nanocomposite synthesized via a greener microwave-assisted ionic liquid (IL) method toward potential antibiotic toxicity reduction. Following the synthesis of CoFe2O4 and WO3 nanostructures using IL as the greener medium and a microwave-assisted process, a subsequent modification was carried out by in situ polymerizations of PANI with the prepared nanostructures to yield the ternary nanocomposite. Detailed structural and morphological analyses revealed the close interfacial interaction between the three components of the ternary heterojunction. The photoelectrochemical and optical studies indicated possible fast electron transfer, light-sensitive channelization, and a prolonged excited-state lifetime for the ternary p–n–n heterojunction. Superior visible-light-assisted photodegradation of toxic tetracycline (TCL) antibiotics with Kapp = 0.0557 min–1 was obtained using the heterojunction, exhibiting considerable recyclability over six catalytic cycles. A standard Trypan blue exclusion assay method was employed to assess the nontoxicity nature of the ternary photocatalyst and phototreated TCL solutions. Finally, a suitable photocatalytic mechanism of dual Z-scheme charge carrier channelization was proposed from multiple experimental and analytical studies such as X-ray photoelectron spectroscopy, trapping of active radicals, and quantifying the amount of oxygen species produced (HO• and O2•–).