Effect of phenol concentration on the photocatalytic performance of ZnO nanoparticles

Effect of phenol concentration on the photocatalytic performance of ZnO nanoparticles

BACKGROUND Phenol and its derivatives are considered toxic compounds, even at low concentrations. Their accumulation in water effluents has become a serious problem that could be resolved by using zinc oxide (ZnO)‐based photocatalysts. RESULTS ZnO nanoparticles were synthesized through the precipita...

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Bibliographic Details
Published in:Journal of chemical technology and biotechnology (1986) Vol. 98; no. 8; pp. 1826 - 1836
Main Authors: González, Rosendo López, Fuente, Orbelin, García, Ruth Lezama, Carmen Uribe López, Melina, Owen, Patricia Quintana, López, María Carmen Hidalgo, Lemus, Mayra Angélica Alvarez
Format: Journal Article
Language:English
Published: Chichester, UK John Wiley & Sons, Ltd 01-08-2023
Wiley Subscription Services, Inc
Subjects:
Catalytic activity
Crystallites
Crystals
Fluorescence
Fluorescence spectroscopy
Free radicals
Hydroxyl radicals
Low concentrations
Nanoparticles
phenol degradation
Phenols
Photocatalysis
Photocatalysts
Reagents
Sodium carbonate
Spectrum analysis
Synthesis
Wurtzite
Zinc oxide
Zinc oxides
ZnO nanoparticles
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Summary:BACKGROUND Phenol and its derivatives are considered toxic compounds, even at low concentrations. Their accumulation in water effluents has become a serious problem that could be resolved by using zinc oxide (ZnO)‐based photocatalysts. RESULTS ZnO nanoparticles were synthesized through the precipitation method, using zinc nitrate and sodium carbonate as reagents. The as‐synthesized powder was calcined for 4 h at 500 °C (2° C min−1). X‐Ray diffraction analysis confirmed a hexagonal crystalline phase (wurtzite) with an average crystallite size of 38 nm. The Kubelka‐Munk method was used to determine a band gap of 3.27 eV through UV–Vis diffuse reflectance spectrum and a Brunauer‐Emmett‐Teller (BET) specific area of 12 m2 g−1 was obtained from N2 adsorption analysis. The photocatalytic activity of ZnO was evaluated under visible light (300 W) lamp, with 1 mg mL−1 of photocatalyst and using phenol solutions at different concentrations of 5, 10, 25, and 50 ppm; the obtained degradation percentages were 98%, 97%, 94%, and 71%, respectively. Three cycles were performed with the ZnO used in the reactions with phenol at 5 and 50 ppm, decreasing the degraded percentages to 87% and 65%, respectively. The generation of hydroxyl radicals was estimated for the ZnO and ZnO samples after three cycles by means of fluorescence spectroscopy analysis. It was observed that the first‐used ZnO material generated a significant amount of hydroxyl radicals. CONCLUSION When compared to ZnO after three cycles of reaction, the amount of generated hydroxyl radicals decreased. It was observed that the higher the amount of phenol, the lower the generation of hydroxyl radicals after reuse; this was probably due to the presence of some adsorbed by‐products of the photocatalytic reaction on the surface of ZnO, as the FTIR spectrum of the post‐reaction sample showed. © 2023 Society of Chemical Industry (SCI).
ISSN:0268-2575
1097-4660
DOI:10.1002/jctb.7334