Parasitic light absorption, rate laws and heterojunctions in the photocatalytic oxidation of arsenic(III) using composite TiO2/Fe2O3
File(s)
Supporting information
Author(s)
Bullen, Jay Calum
Heiba, Hany F
Kafizas, Andreas
Weiss, Dominik J
Type
Journal Article
Abstract
Composite photocatalyst-adsorbents such as TiO2/Fe2O3 are promising materials for the one-step treatment of arsenite contaminated water. However, no previous study has investigated how coupling TiO2 with Fe2O3 influences the photocatalytic oxidation of arsenic(III). Herein, we develop new hybrid experiment/modelling approaches to study light absorption, charge carrier behaviour and changes in the rate law of the TiO2/Fe2O3 system, using UV-Vis spectroscopy, transient absorption spectroscopy (TAS), and kinetic analysis. Whilst coupling TiO2 with Fe2O3 improves total arsenic removal by adsorption, oxidation rates significantly decrease (up to a factor of 60), primarily due to the parasitic absorption of light by Fe2O3 (88% of photons at 368 nm) and secondly due to changes in the rate law from disguised zero-order kinetics to first-order kinetics. Charge transfer across this TiO2-Fe2O3 heterojunction is not observed. Our study demonstrates the first application of a multi-adsorbate surface complexation model (SCM) towards describing As(III) oxidation kinetics which, unlike Langmuir-Hinshelwood kinetics, includes the competitive adsorption of As(V), and we further highlight the importance of parasitic light absorption and catalyst fouling when designing heterogeneous photocatalysts for As(III) remediation.
Date Issued
2022-02-03
Date Acceptance
2022-02-03
Citation
Chemistry: A European Journal, 2022, 28 (6)
ISSN
0947-6539
Publisher
Wiley
Journal / Book Title
Chemistry: A European Journal
Volume
28
Issue
6
Copyright Statement
© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Sponsor
British Council (UK)
Engineering & Physical Science Research Council (E
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/35114042
Grant Number
20147-RLWK8-10774
EP/P510798/1
Subjects
Arsenic
Water treatment
composite
photocatalysis
photocatalytic oxidation
Publication Status
Published online
Coverage Spatial
Germany
Article Number
ARTN e202104181
Date Publish Online
2022-02-03