Delarmelina, Maicon;
Dlamini, Mbongiseni W;
Pattisson, Samuel;
Davies, Philip R;
Hutchings, Graham J;
Catlow, C Richard A;
(2023)
The effect of dissolved chlorides on the photocatalytic degradation properties of titania in wastewater treatment.
Physical Chemistry Chemical Physics
10.1039/d2cp03140j.
(In press).
Preview |
Text
d2cp03140j.pdf - Published Version Download (5MB) | Preview |
Abstract
We investigate the effect of chlorides on the photocatalytic degradation of phenol by titania polymorphs (anatase and rutile). We demonstrate how solubilised chlorides can affect the hydroxyl radical formation on both polymorphs with an overall effect on their photodegradative activity. Initially, the photocatalytic activity of anatase and rutile for phenol degradation is investigated in both standard water and brines. With anatase, a significant reduction of the phenol conversion rate is observed (from a pseudo-first-order rate constant k = 5.3 × 10−3 min−1 to k = 3.5 × 10−3 min−1). In contrast, the presence of solubilised chlorides results in enhancement of rutile activity under the same reaction conditions (from 2.3 × 10−3 min−1 to 4.8 × 10−3 min−1). Periodic DFT methods are extensively employed and we show that after the generation of charge separation in the modelled titania systems, adsorbed chlorides are the preferential site for partial hole localisation, although small energy differences are computed between partially localised hole densities over adsorbed chloride or hydroxyl. Moreover, chlorides can reduce or inhibit the ability of r-TiO2 (110) and a-TiO2 (101) systems to localise polarons in the slab structure. These results indicate that both mechanisms – hole scavenging and the inhibition of hole localisation – can be the origin of the effect of chlorides on photocatalytic activity of both titania polymorphs. These results provide fundamental insight into the photocatalytic properties of titania polymorphs and elucidate the effect of adsorbed anions over radical formation and oxidative decomposition of organic pollutants.
| Type: | Article |
|---|---|
| Title: | The effect of dissolved chlorides on the photocatalytic degradation properties of titania in wastewater treatment |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1039/d2cp03140j |
| Publisher version: | https://doi.org/10.1039/D2CP03140J |
| Language: | English |
| Additional information: | This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10163783 |
Archive Staff Only
 |
View Item |
