Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts
The synthesis and structural characterization of synthetic zinc oxide and halloysite-based zinc oxide nanocomposites (with 2–28 m/m% ZnO content) are presented. The chemical precipitation of zinc hydroxide precursors and its subsequent drying at 80 °C yielded dominantly zinc oxide (zincite). Thermal...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-04-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/4/476 |
| _version_ | 1797409983879446528 |
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| author | Balázs Zsirka Veronika Vágvölgyi Erzsébet Horváth Tatjána Juzsakova Orsolya Fónagy Erzsébet Szabó-Bárdos János Kristóf |
| author_facet | Balázs Zsirka Veronika Vágvölgyi Erzsébet Horváth Tatjána Juzsakova Orsolya Fónagy Erzsébet Szabó-Bárdos János Kristóf |
| author_sort | Balázs Zsirka |
| collection | DOAJ |
| description | The synthesis and structural characterization of synthetic zinc oxide and halloysite-based zinc oxide nanocomposites (with 2–28 m/m% ZnO content) are presented. The chemical precipitation of zinc hydroxide precursors and its subsequent drying at 80 °C yielded dominantly zinc oxide (zincite). Thermal treatment at 350 °C completely transformed the remaining precursor to ZnO without causing structural dehydroxylation of the halloysite support. The procedure yielded zinc oxide nanoparticles with 10–22 nm average size having quasi-spherical scale-like morphology. The specific surface area of the synthetic zinc oxide was found to be low (13 m<sup>2</sup>/g), which was significantly enhanced after nanocomposite preparation (27–47 m<sup>2</sup>/g). The photocatalytic activity of the prepared nanocomposites was probed by the degradation of a phenolic compound (4-nitrophenol) upon UV irradiation in liquid phase. Compared to their individual constituents, an increased activity of the nanocomposites was observed, while the SSA-normalized photocatalytic activity revealed a synergic effect in nanocomposites above 9 m/m% ZnO content. The nanocomposites were found to be stable at pH = 5.6, with a minor and major mobilization of zinc ions at pH = 12.4 and pH = 1.9, respectively. The toxicity of leachates in different pH environments by <i>Vibrio fischeri</i> bioluminescence indicated low toxicity for ZnO nanoparticles and insignificant toxicity for the nanocomposites. The enhanced photocatalytic activity together with the lower toxicity of the halloysite-ZnO nanocomposites highlight their application potential in water treatment. |
| first_indexed | 2024-03-09T04:22:24Z |
| format | Article |
| id | doaj.art-de81b28ac5bd4e1b8dc721b90112507f |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T04:22:24Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-de81b28ac5bd4e1b8dc721b90112507f2023-12-03T13:45:49ZengMDPI AGMinerals2075-163X2022-04-0112447610.3390/min12040476Halloysite-Zinc Oxide Nanocomposites as Potential PhotocatalystsBalázs Zsirka0Veronika Vágvölgyi1Erzsébet Horváth2Tatjána Juzsakova3Orsolya Fónagy4Erzsébet Szabó-Bárdos5János Kristóf6Research Group of Analytical Chemistry/Laboratory for Surfaces and Nanostructures, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Analytical Chemistry/Laboratory for Surfaces and Nanostructures, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Analytical Chemistry/Laboratory for Surfaces and Nanostructures, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungarySustainability Solutions Research Lab, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Environmental and Inorganic Photochemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Environmental and Inorganic Photochemistry, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryResearch Group of Analytical Chemistry/Laboratory for Surfaces and Nanostructures, Center for Natural Sciences, University of Pannonia, P.O. Box 158, 8201 Veszprem, HungaryThe synthesis and structural characterization of synthetic zinc oxide and halloysite-based zinc oxide nanocomposites (with 2–28 m/m% ZnO content) are presented. The chemical precipitation of zinc hydroxide precursors and its subsequent drying at 80 °C yielded dominantly zinc oxide (zincite). Thermal treatment at 350 °C completely transformed the remaining precursor to ZnO without causing structural dehydroxylation of the halloysite support. The procedure yielded zinc oxide nanoparticles with 10–22 nm average size having quasi-spherical scale-like morphology. The specific surface area of the synthetic zinc oxide was found to be low (13 m<sup>2</sup>/g), which was significantly enhanced after nanocomposite preparation (27–47 m<sup>2</sup>/g). The photocatalytic activity of the prepared nanocomposites was probed by the degradation of a phenolic compound (4-nitrophenol) upon UV irradiation in liquid phase. Compared to their individual constituents, an increased activity of the nanocomposites was observed, while the SSA-normalized photocatalytic activity revealed a synergic effect in nanocomposites above 9 m/m% ZnO content. The nanocomposites were found to be stable at pH = 5.6, with a minor and major mobilization of zinc ions at pH = 12.4 and pH = 1.9, respectively. The toxicity of leachates in different pH environments by <i>Vibrio fischeri</i> bioluminescence indicated low toxicity for ZnO nanoparticles and insignificant toxicity for the nanocomposites. The enhanced photocatalytic activity together with the lower toxicity of the halloysite-ZnO nanocomposites highlight their application potential in water treatment.https://www.mdpi.com/2075-163X/12/4/476halloysitezinc oxidenanocompositestructural characterizationphotocatalytic activity |
| spellingShingle | Balázs Zsirka Veronika Vágvölgyi Erzsébet Horváth Tatjána Juzsakova Orsolya Fónagy Erzsébet Szabó-Bárdos János Kristóf Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts Minerals halloysite zinc oxide nanocomposite structural characterization photocatalytic activity |
| title | Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts |
| title_full | Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts |
| title_fullStr | Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts |
| title_full_unstemmed | Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts |
| title_short | Halloysite-Zinc Oxide Nanocomposites as Potential Photocatalysts |
| title_sort | halloysite zinc oxide nanocomposites as potential photocatalysts |
| topic | halloysite zinc oxide nanocomposite structural characterization photocatalytic activity |
| url | https://www.mdpi.com/2075-163X/12/4/476 |
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