Photodegradation of Ciprofloxacin and Levofloxacin by Au@ZnONPs-MoS2-rGO Nanocomposites

Abstract

This study aimed to investigate the photocatalytic performance of diverse zinc oxide catalysts containing gold nanoparticles (AuNPs), molybdenum disulfide (MoS2), and reduced graphene oxide (rGO) toward the degradation of the antibiotics levofloxacin (LFX) and ciprofloxacin (CFX) in aqueous solutions. The obtained results demonstrate that LFX is more resistant to degradation when compared with CFX and that the principal route of degradation under visible light is the formation of hydroxyl radicals. Photoluminescence (PL) measurements were employed to verify the inhibitory effect of electron–hole recombination when AuNPs, MoS2, and rGO are integrated into a semiconductor. The catalyst that achieved the highest percentage of CFX degradation was 1%Au@ZnONPs-3%MoS2-1%rGO, exhibiting a degradation efficiency of 96%, while the catalyst that exhibited the highest percentage of LFX degradation was 5%Au@ZnONPs-3%MoS2-1%rGO, displaying a degradation efficiency of 99.8%. A gas chromatography–mass spectrometry (GC-MS) analysis enabled the identification of reaction intermediates, facilitating the determination of a potential degradation pathway for both antibiotics. Additionally, recyclability assessments showed that the synthesized catalysts maintained stable photocatalytic efficiencies after 15 cycles, indicating that the heterostructures have the potential for further usage and may be tested with other organic contaminants as well.

Synergistic Effects of Co3O4-gC3N4-Coated ZnO Nanoparticles: A Novel Approach for Enhanced Photocatalytic Degradation of Ciprofloxacin and Hydrogen Evolution via Water Splitting

“…In another significant study, Swaminathan et al [ 54 ] documented over 98% CFX photodegradation in 1 h with a ternary system based on rGO, BiVO 4 , and ZnO. Our research group has recently observed analogous results employing Au@ZnONPs-MoS 2 -rGO nanocomposites [ 5 ], with a 96% photodegradation rate of CFX in 1 h. The simultaneous application of catalysts for both decontamination processes and hydrogen production is markedly underrepresented in the existing literature. However, the results of our current investigation, achieving hydrogen production rates exceeding 1400 mmol/hg, are decidedly noteworthy within this context.…”

“…The intermediate P7, reported previously in the literature [ 39 ], as observed in the potential degradation pathway in Figure 7 , generates various oxidation products that, in general, retain an aromatic ring derived from the quinoline nucleus. From the intermediate P11, compounds P16 and P18 are obtained, which have already been reported in the literature [ 5 , 40 ]. The smaller intermediates are much less recalcitrant to degradation; therefore, they undergo very rapid transformation processes, resulting in much smaller molecules that are more challenging to identify.…”

“…On the other hand, the growing prevalence of antibiotic-resistant bacteria is an escalating public health emergency that undermines decades of medical advancements in treating bacterial infections [ 5 ]. The improper disposal of antibiotics, especially into water systems, not only contaminates natural water sources but also facilitates the development of drug-resistant strains of bacteria [ 6 ].…”

B2O3‐Nanoparticles‐Decorated N‐Rich Reduced Graphene Oxide Composites for the Enhanced Visible‐Light‐Assisted Photocatalytic Degradation of Ciprofloxacin

“…Furthermore, Machin et al investigated the photocatalytic activity of multi‐metal‐based rGO nanocomposite, prepared using ZnO catalysts containing Au NPs, molybdenum disulfide, and rGO for the degradation of the levofloxacin and CIP in aqueous solution. [ 11 ] They concluded that photogenerated electron–hole recombination was delayed by MoS 2 and rGO sheets. In other investigations, the flower‐like Bi 2 WO 6 architectures were used to fabricate rGO/Bi 2 WO 6 composites to photodegradation CIP wastewater in stimulated visible light.…”