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Parasitic light absorption, rate laws and heterojunctions in the photocatalytic oxidation of arsenic(III) using composite TiO2/Fe2O3

Title: Parasitic light absorption, rate laws and heterojunctions in the photocatalytic oxidation of arsenic(III) using composite TiO2/Fe2O3
Authors: Bullen, JC
Heiba, HF
Kafizas, A
Weiss, DJ
Item 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.
Issue Date: 3-Feb-2022
Date of Acceptance: 3-Feb-2022
URI: http://hdl.handle.net/10044/1/95124
DOI: 10.1002/chem.202104181
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.
Sponsor/Funder: British Council (UK)
Engineering & Physical Science Research Council (E
Funder's Grant Number: 20147-RLWK8-10774
EP/P510798/1
Keywords: Science & Technology
Physical Sciences
Chemistry, Multidisciplinary
Chemistry
arsenic
composite
photocatalysis
photocatalytic oxidation
water treatment
CHARGE SEPARATION
ARSENITE
WATER
REMOVAL
DISSOLUTION
KINETICS
NANOPARTICLES
BANGLADESH
ADSORPTION
HEMATITE
arsenic
composite
photocatalysis
photocatalytic oxidation
water treatment
Arsenic
Water treatment
composite
photocatalysis
photocatalytic oxidation
General Chemistry
03 Chemical Sciences
Publication Status: Published online
Conference Place: Germany
Article Number: ARTN e202104181
Online Publication Date: 2022-02-03
Appears in Collections:Chemistry
Earth Science and Engineering
Faculty of Natural Sciences
Faculty of Engineering



This item is licensed under a Creative Commons License Creative Commons