Synthesis of visible light active MoS2 nanoparticles for the photocatalytic degradation of ciprofloxacin: Kinetics, mechanism and toxicity investigations

초록

Transition metal dichalcogenide based nanomaterials are currently gaining considerable attention due to their potential photocatalytic applications. Herein, a transition metal dichalcogenide, MoS2 nanoparticles (NPs), was synthesized via hydrothermal treatment. The as-prepared MoS2 NPs was characterized by various analytical techniques such as FTIR, XRD, XPS, SEM, UV-vis diffuse reflectance spectroscopy (DRS) and EDX. The bandgap energy of MoS2 was calculated to be 1.9 eV. In addition, the photocatalytic activity of the MoS2 was evaluated by ciprofloxacin (CIP) degradation under visible light irradiation, achieving 80.3% of CIP degradation. Furthermore, the effect of H2O2 was investigated on photocatalytic degradation CIP, showing its positive role in degradation efficiency. The photocatalytic degradation of CIP was found to be 98.2% at 240 min of visible light irradiation at pH 5.0 using 0.5 g L-1 MoS2 NPs and 1 mM of H2O2. The effects of different operational parameters, such as solution pH, catalyst dosage, CIP concentrations and inorganic anions (Cl-and NO3-), on photocatalytic degradation of CIP were evaluated. The degradation was reduced from 98.2% to 90.4 and 81.7% with addition of 5 mM of each Cl-and NO3-, respectively. Moreover, the pH significantly affected the photo-catalytic degradation of CIP, acheiving higher degradation efficiency. Furthermore, the aquatic toxicity of degradation products was computationally predicted using the ECOSAR program. Additionally, frontier electron density calculations were used to predict the reactive sites in CIP molecule. The present study suggests that MoS2-based photocatalysts has the potential to degrade CIP under visible light irradiation thereby protecting the aquatic lives from harmful effects of contaminated water.

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