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Behavioral analysis of simultaneous photo-electro-catalytic degradation of antibiotic resistant: E. coli and antibiotic via ZnO/CuI: A kinetic and mechanistic study

Gupta, R and Modak, JM and Madras, G (2019) Behavioral analysis of simultaneous photo-electro-catalytic degradation of antibiotic resistant: E. coli and antibiotic via ZnO/CuI: A kinetic and mechanistic study. In: Nanoscale Advances, 1 (10). pp. 3992-4008.

nan_sca_adv_ 1-10 _3992 - 4008.2019.pdf - Published Version

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Official URL: https://doi.org/10.1039/c9na00483a


Visible light responsive semiconductor-based photocatalysis is known to be an efficient method for the disinfection of bacterial cells. Here, we address the issue of aqueous contamination by persistent pollutants such as antibiotics and antibiotic resistant bacteria (ARB) from an innovative angle. Simultaneous degradation of an antibiotic (chloramphenicol) and antibiotic resistant bacteria (chloramphenicol resistant E. coli) is performed to observe the effect of the presence of antibiotic in the reaction system when it is required for survival of the bacteria. A p-n junction-based ZnO/CuI composite is shown to demonstrate drastic enhancement in photocatalytic activity due to the inbuilt potential barrier suppressing charge carrier recombination. Moreover, an additional driving force for the suppression of recombination was provided by using a potential bias. Hydrothermally grown ZnO/CuI electrode films were characterized to assess optical, electrochemical, physicochemical and structural properties of the composite. Electrochemical impedance spectroscopy and diffuse reflectance spectroscopy were performed to obtain insights into the band bending, band edge potential, band gap and transmittance of the semiconductors. X-ray-based spectroscopic methods and zeta potential measurement demonstrated the surface properties and surface charges of the moieties in the reaction system, allowing us to deduce justifiable conclusions. A model based on the interaction of photogenerated radicals with the bacteria was developed and rate expressions were used to obtain the rate constants for the experimental results. Photoelectrocatalysis and photocatalysis followed first order rate kinetics; however, due to the unavailability of direct hole attack in photolysis, the electrolysis and electrocatalysis followed Langmuir-Hinshelwood kinetics. Bacterial disinfection was confirmed by K+ ion leaching and by structural changes in the membrane observed by FTIR of the cells after the reaction. We also addressed the issue of bacterial adhesion on the films restricting the mobility of radicals to interact with the bacteria, affecting the reusability of the catalyst films. The present work opens a wide avenue to discuss and address the improvement of the reusability of nanomaterial films for bacterial applications by controlling bacterial adhesion. © 2019 The Royal Society of Chemistry.

Item Type: Journal Article
Publication: Nanoscale Advances
Publisher: Royal Society of Chemistry
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Adhesion; Biodegradation; Composite films; Disinfection; Electrocatalysis; Electrochemical impedance spectroscopy; Energy gap; Escherichia coli; Fourier transform infrared spectroscopy; II-VI semiconductors; Kinetics; Photocatalytic activity; Photolysis; Physicochemical properties; Rate constants; Reusability; Semiconductor junctions; Spectroscopic analysis; Wide band gap semiconductors; Zinc oxide, Antibiotic-resistant bacteria; Charge carrier recombination; Diffuse reflectance spectroscopy; Langmuir-Hinshelwood kinetics; Photo-electrocatalysis; Simultaneous degradation; Visible light responsive; Zeta potential measurements, Antibiotics
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Date Deposited: 25 Oct 2022 12:04
Last Modified: 25 Oct 2022 12:04
URI: https://eprints.iisc.ac.in/id/eprint/77576

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