W-Doped ZnO Photocatalyst for the Degradation of Glyphosate in Aqueous Solution

Abstract

In this paper, the photocatalytic degradation of glyphosate by zinc oxide (ZnO) photocatalysts doped with tungsten (W) was investigated under solar simulated light. The photocatalysts were successfully synthesized through a simple precipitation method and subsequently characterized by different techniques: Raman spectroscopy, UV–Vis, N2 adsorption at −196 °C, X-ray diffraction, and SEM analysis. In particular, all the prepared catalysts were characterized by a crystallite size of about 28 nm and a hexagonal wurtzite structure. After the W doping, the bandgap energy decreased from 3.22 of pure ZnO to 3.19 for doped ZnO. This allowed us to obtain good results in terms of glyphosate degradation and simultaneous mineralization under solar simulated lamps, making the process environmentally friendly and with almost zero energy costs. In particular, the best photocatalytic performance was obtained with 100 W-ZnO (prepared with 1.5 mol % of W). With this catalyst, after 180 min of exposure to solar simulated light, the glyphosate degradation and mineralization was equal to 74% and 30%, respectively. Furthermore, it has been shown that the best catalyst dosage was equal to 1.5 g/L. The study on the influence of pH evidenced that the best photocatalytic performances are obtained at spontaneous (neutral) pH conditions. Finally, to determine the main reactive species in the glyphosate oxidation, the effects of different radical scavengers were tested. The results evidenced that the glyphosate oxidation mechanism seems to be related mainly to the O2•− generated under simulated solar light irradiation, but also in minor part to h+.

Visible-Light-Driven Photocatalytic Inactivation of Bacteria, Bacteriophages, and Their Mixtures Using ZnO-Coated HDPE Beads as Floating Photocatalyst

“…The characteristic diffraction peaks of ZnO at 2Θ = 31.7 • , 34.5 • , 36.2 • , 47.5 • , 56.6 • , 62.9 • , and 68.0 • correspond to (100), (002), ( 101), ( 102), (110), (103), and (112) crystal planes, respectively. This is totally consistent with the XRD analysis of ZnO reported in the literature [54][55][56]. It can be observed that the predominant crystal plane is (002), commonly found in the films deposited by sputtering technique due to the minimum surface energy of (002) which results in higher crystallites orientation rate along the c-axis [57][58][59].…”

Tailoring Vanadium-Based Magnetic Catalyst by In Situ Encapsulation of Tungsten Disulfide and Applications in Abatement of Multiple Pollutants

“…The WV-MNPs were used for the antimicrobial activity of the Escherichia coli bacterial strain and to find out the inevitable photodegradation of CR as well as glyphosate. In terms of performance, the newly designed photocatalyst outperformed various previously reported catalysts applied for the degradation of targeted pollutants. ,, …”

“…In terms of performance, the newly designed photocatalyst outperformed various previously reported catalysts applied for the degradation of targeted pollutants. 25,33,34 2. EXPERIMENTAL SECTION 2.1.…”

Recent Advances in Endocrine Disrupting Compounds Degradation through Metal Oxide-Based Nanomaterials

“…The excellent photocatalytic efficiency was explained as due not only to the morphology and defectivity, but also on the role of bonded citric acid as electron donor, fostering the regeneration of Ce 3+ sites by ligand-to-metal charge transfer. On the other hand, W-doped ZnO showing large wurtzite crystallites was prepared by a simple precipitation method and tested in PMG photodegradation under simulated solar light [110]. The optimal doping amount was found to be 1.5 mol%, providing 74% removal and 30% mineralization in 180 min with 1.5 g/L catalyst dosage.…”