Enhanced solar-driven photocatalytic decomposition of ciprofloxacin antibiotic and Orange G dye using innovative g-C3N4/BiOCl/Ag2MoO4 nanocomposites: Experimental and Monte Carlo simulation studies

Abstract

This study explores the production and application of a nanomaterial composed of g-C₃N₄, BiOCl, and Ag₂MoO₄ for the photocatalytic degradation of Orange G dye (OG) and Ciprofloxacin antibiotic (CIP). The synthesized nanocomposite photocatalyst (g-C₃N4/BiOCl/Ag₂MoO₄), along with the individual photocatalysts (g-C₃N₄, BiOCl, and Ag₂MoO₄), were thoroughly characterized. This included analysing their crystallinity using XRD, structure with FTIR, morphology through SEM and TEM, and composition and valence states using EDX and XPS. The characterization examination approves the successful formation of g-C₃N₄/BiOCl/Ag₂MoO₄ nanoparticles with high crystallinity. The photocatalytic results indicated that the ternary nanocomposite is very effective at degrading pollutant molecules, achieving a 97 % reduction in Orange G in 60 min and a 90 % reduction in Ciprofloxacin in 100 min, facilitated by redox reactions powered by solar energy.

Ultimately, the recyclable nature of the nanocomposite photocatalyst demonstrates its sustained photocatalytic efficacy over four cycles. Furthermore, through UV–vis diffuse reflectance spectroscopy (DRS) and active species capture, a proposed photocatalytic mechanism elucidates the enhanced performance of g-C₃N₄/BiOCl/Ag₂MoO₄. In simulation calculations, DFT was used to optimize the structures. Then, Monte Carlo simulations were applied to investigate the adsorption mechanism of the OG and CIP molecules on g-C₃N₄/BiOCl/Ag₂MoO₄ surface. As a result, the adsorption of OG on nanocomposite was higher than the adsorption of CIP on g-C₃N₄/BiOCl/Ag₂MoO₄ surface due to its high negative energy.