Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst
Due to its toxicity, 4-chlorophenol (4CP) must be removed from the wastewater before discharging into open water. In this work, ZnO and Ag-ZnO photocatalysts were prepared via a solvothermal method under mild conditions (150 °C), followed by calcination at 300 °C and then characterized. The addition...
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Chemistry Department, Universitas Gadjah Mada, Indonesia
2022
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| author | Razali, Nur Syafiqa Hazirah Mohamad Mukhair, Hayati Lee, Kian Mun Saiman, Mohd Izham Abdullah, Abdul Halim |
| author_facet | Razali, Nur Syafiqa Hazirah Mohamad Mukhair, Hayati Lee, Kian Mun Saiman, Mohd Izham Abdullah, Abdul Halim |
| author_sort | Razali, Nur Syafiqa Hazirah |
| collection | UPM |
| description | Due to its toxicity, 4-chlorophenol (4CP) must be removed from the wastewater before discharging into open water. In this work, ZnO and Ag-ZnO photocatalysts were prepared via a solvothermal method under mild conditions (150 °C), followed by calcination at 300 °C and then characterized. The addition of Ag resulted in a change of the ZnO morphologies, which exhibited wurtzite structure, from irregular to rod-like shape, lower bandgap energy, and a lower electron-hole recombination rate. The 0.6 Ag-ZnO catalyst showed the highest efficiency in the photooxidation of 4CP under UV irradiation. Molecular 4CP exists in acidic and near-neutral conditions (pH 4 and 6) and is stable towards UV irradiation. Photooxidation of 2.3 × 10–4 mol/L 4CP by 0.8 g of 0.6% Ag-ZnO resulted in 67% removal of molecular 4CP at pH 6 with a rate constant of 4.0 × 10–3 min–1. Under similar conditions, a complete photooxidation of the anionic 4CP was observed at pH 11 with a rate constant of 1.4 × 10–2 min–1. The holes and superoxide radicals are the species responsible for molecular 4CP photoooxidation, while hydroxyl radicals are the dominant species for anionic 4CP. The prepared Ag/ZnO photocatalyst exhibit good potential to efficiently oxidize 4CP in both acidic and alkaline conditions. |
| first_indexed | 2024-03-06T11:14:47Z |
| format | Article |
| id | upm.eprints-101142 |
| institution | Universiti Putra Malaysia |
| last_indexed | 2024-03-06T11:14:47Z |
| publishDate | 2022 |
| publisher | Chemistry Department, Universitas Gadjah Mada, Indonesia |
| record_format | dspace |
| spelling | upm.eprints-1011422023-05-23T07:09:55Z http://psasir.upm.edu.my/id/eprint/101142/ Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst Razali, Nur Syafiqa Hazirah Mohamad Mukhair, Hayati Lee, Kian Mun Saiman, Mohd Izham Abdullah, Abdul Halim Due to its toxicity, 4-chlorophenol (4CP) must be removed from the wastewater before discharging into open water. In this work, ZnO and Ag-ZnO photocatalysts were prepared via a solvothermal method under mild conditions (150 °C), followed by calcination at 300 °C and then characterized. The addition of Ag resulted in a change of the ZnO morphologies, which exhibited wurtzite structure, from irregular to rod-like shape, lower bandgap energy, and a lower electron-hole recombination rate. The 0.6 Ag-ZnO catalyst showed the highest efficiency in the photooxidation of 4CP under UV irradiation. Molecular 4CP exists in acidic and near-neutral conditions (pH 4 and 6) and is stable towards UV irradiation. Photooxidation of 2.3 × 10–4 mol/L 4CP by 0.8 g of 0.6% Ag-ZnO resulted in 67% removal of molecular 4CP at pH 6 with a rate constant of 4.0 × 10–3 min–1. Under similar conditions, a complete photooxidation of the anionic 4CP was observed at pH 11 with a rate constant of 1.4 × 10–2 min–1. The holes and superoxide radicals are the species responsible for molecular 4CP photoooxidation, while hydroxyl radicals are the dominant species for anionic 4CP. The prepared Ag/ZnO photocatalyst exhibit good potential to efficiently oxidize 4CP in both acidic and alkaline conditions. Chemistry Department, Universitas Gadjah Mada, Indonesia 2022-06 Article PeerReviewed Razali, Nur Syafiqa Hazirah and Mohamad Mukhair, Hayati and Lee, Kian Mun and Saiman, Mohd Izham and Abdullah, Abdul Halim (2022) Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst. Indonesian Journal of Chemistry, 22 (3). 805 - 817. ISSN 1411-9420; ESSN: 2460-1578 https://jurnal.ugm.ac.id/ijc/article/view/71763 10.22146/ijc.71763 |
| spellingShingle | Razali, Nur Syafiqa Hazirah Mohamad Mukhair, Hayati Lee, Kian Mun Saiman, Mohd Izham Abdullah, Abdul Halim Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title | Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title_full | Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title_fullStr | Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title_full_unstemmed | Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title_short | Effect of solution pH on the photo-oxidation of 4-chlorophenol by synthesized silver-zinc oxide photocatalyst |
| title_sort | effect of solution ph on the photo oxidation of 4 chlorophenol by synthesized silver zinc oxide photocatalyst |
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