Influence of parameters and radical scavengers on the visible-light-induced degradation of ciprofloxacin in ZnO/SnS2 nanocomposite suspension: Identification of transformation products

Abstract

Removal of ciprofloxacin (CIP) pollutant from wastewater using conventional process is particularly challenging due to poor removal efficiency. In this work, CIP was photocatalytically degraded using a porous ZnO/SnS2 photocatalyst prepared via microwaves. The influence of process parameters (e.g., pH, catalyst mass and initial CIP concentration) and radical scavengers on visible-light induced degradation of CIP on the catalyst was investigated. From the study, it was found that visible-light induced degradation of CIP on ZnO/SnS2 is a surface-mediated process and the reaction kinetics followed the Langmuir-Hinshelwood first-order kinetics. It was found that the optimum condition for CIP degradation was at pH of 6.1 and catalyst dosage of 500 mg L−1. Higher catalyst dosage however led to a decline in reaction rate due to light scattering effect and reduction in light penetration.

Controlled growth of ZnO nanoparticles using ethanolic root extract of Japanese knotweed: photocatalytic and antimicrobial properties

“…In our case, the degradation was only slightly faster compared to H 2 O, indicating that 1 O 2 does not contribute significantly to the overall degradation mechanism. Most of these findings are in accordance with a similar study by Makama et al , 45 who reported that hydroxyl radicals have a marginal role in the degradation mechanism, while valence band holes (h + ) contributed the most to the degradation of ciprofloxacin. The main difference is that they found free electrons (e − ) to have a minor to no effect on degradation ( Fig.…”

Zn/La Mixed Oxides Prepared by Coprecipitation: Synthesis, Characterization and Photocatalytic Studies

“…It should be kept in mind that some of the potential adsorption sites for CA from the photocatalyst remain for a time unavailable for the adsorption, since the primary degradation products are formed during the reaction on the surface, in adsorbed state and a delay appears in rendering the active sites free from them by desorption. This effect is more pronounced at high initial concentrations [50].…”

“…In a photocatalytic process, the catalyst loading is a key aspect to be considered, because of its effect on the pollutant oxidation rate. In addition, this parameter dictates the economic viability for a possible future process implementation [49,50]. For these considerations, it is of utmost importance to obtain more insights about the effect of this parameter on the photocatalytic degradation efficiency.…”

ZnO–SnO2–Sn nanocomposite as photocatalyst in ultraviolet and visible light

“…The kinetics of the degradation process of MB and RB dyes were determined for the materials with the highest photocatalytic efficiency under UV (ZnO-SnO 2 (10)-Sn(1)) and visible light (ZnO-SnO 2 (10)-Sn( 5)). The pseudo-first-order Langmuir-Hinshelwood (L-H) kinetics model was used to determine the rate constant of the photodegradation reaction (Makama et al 2020):…”