Comparison of TiO[sub.2] and ZnO for Heterogeneous Photocatalytic Activation of the Peroxydisulfate Ion in Trimethoprim Degradation

Comparison of TiO[sub.2] and ZnO for Heterogeneous Photocatalytic Activation of the Peroxydisulfate Ion in Trimethoprim Degradation

The persulfate-based advanced oxidation process is a promising method for degrading organic pollutants. Herein, TiO[sub.2] and ZnO photocatalysts were combined with the peroxydisulfate ion (PDS) to enhance the efficiency. ZnO was significantly more efficient in PDS conversion and SO[sub.4] [sup.•−]...

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Bibliographic Details
Published in:Materials 2023-08, Vol.16 (17)
Main Authors: Náfrádi, Máté, Alapi, Tünde, Veres, Bence, Farkas, Luca, Bencsik, Gábor, Janáky, Csaba
Format: Article
Language:eng
Subjects:
Analysis
Antibacterial agents
Purification
Sewage
Trimethoprim
Wastewater
Water pollution
Zinc oxide
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Summary:The persulfate-based advanced oxidation process is a promising method for degrading organic pollutants. Herein, TiO[sub.2] and ZnO photocatalysts were combined with the peroxydisulfate ion (PDS) to enhance the efficiency. ZnO was significantly more efficient in PDS conversion and SO[sub.4] [sup.•−] generation than TiO[sub.2]. For ZnO, the PDS increased the transformation rate of the trimethoprim antibiotic from 1.58 × 10[sup.−7] M s[sup.−1] to 6.83 × 10[sup.−7] M s[sup.−1]. However, in the case of TiO[sub.2], the moderated positive effect was manifested mainly in O[sub.2]-free suspensions. The impact of dissolved O[sub.2] and trimethoprim on PDS transformation was also studied. The results reflected that the interaction of O[sub.2], PDS, and TRIM with the surface of the photocatalyst and their competition for photogenerated charges must be considered. The effect of radical scavengers confirmed that in addition to SO[sub.4] [sup.•−], [sup.•]OH plays an essential role even in O[sub.2]-free suspensions, and the contribution of SO[sub.4] [sup.•−] to the transformation is much more significant for ZnO than for TiO[sub.2]. The negative impact of biologically treated domestic wastewater as a matrix was manifested, most probably because of the radical scavenging capacity of Cl[sup.−] and HCO[sub.3] [sup.−]. Nevertheless, in the case of ZnO, the positive effect of PDS successfully overcompensates that, due to the efficient SO[sub.4] [sup.•−] generation. Reusability tests were performed in Milli-Q water and biologically treated domestic wastewater, and only a slight decrease in the reactivity of ZnO photocatalysts was observed.
ISSN:1996-1944
1996-1944