Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization
Hybrid advanced oxidation processes employed to degrade recalcitrant organic pollutants in water have been widely examined in recent years. In the present work, the potential of TiO<sub>2</sub>-mediated photocatalysis in the presence of the periodate anion (IO<sub>4</sub><...
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MDPI AG
2022-11-01
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| Online Access: | https://www.mdpi.com/2073-4344/12/11/1460 |
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| author | Meriem Bendjama Oualid Hamdaoui Hamza Ferkous Abdulaziz Alghyamah |
| author_facet | Meriem Bendjama Oualid Hamdaoui Hamza Ferkous Abdulaziz Alghyamah |
| author_sort | Meriem Bendjama |
| collection | DOAJ |
| description | Hybrid advanced oxidation processes employed to degrade recalcitrant organic pollutants in water have been widely examined in recent years. In the present work, the potential of TiO<sub>2</sub>-mediated photocatalysis in the presence of the periodate anion (IO<sub>4</sub><sup>−</sup>) toward Safranin O (SO) removal from aqueous solutions was investigated. The findings revealed a high efficiency of the UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> system due to the production of more reactive radicals (<sup>•</sup>OH, IO<sub>3</sub><sup>•</sup> and IO<sub>4</sub><sup>•</sup>) and non-radical species (O<sub>3</sub>, IO<sub>3</sub><sup>−</sup> and IO<sub>4</sub><sup>−</sup>). Additionally, the presence of IO<sub>4</sub><sup>−</sup> as an effective electron acceptor avoids electron-hole recombination, which induces more oxidative reactions at the hole level, increasing the degradation rate of SO. Kinetically, the involvement of IO<sub>4</sub><sup>−</sup> anions in the UV/TiO<sub>2</sub> system enhanced substantially the initial rate of degradation; from 0.295 to 12.07 mg L<sup>−1</sup> min<sup>−1</sup>. The performance of both systems, i.e., UV/TiO<sub>2</sub> and UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup>, was examined under different conditions such as initial dye concentration, photocatalyst loading, periodate dosage, initial solution pH, temperature and dissolved gases. The SO degradation was found to be maximized at low concentration of pollutant at the optimum loading of catalyst (0.4 g L<sup>−1</sup>). The continuous increasing in periodate concentration over the range of 0.01–3 mM improved the system reactivity with no overdose effect. Both systems seemed to be insensitive to minor variations in temperature in the range of 15–45 °C, and showed a strong dependence on initial solution pH where the degradation rates increased proportionally with pH values up to pH 10 and decreased afterwards. A slight negative effect on the photocatalytic removal yield was noted under either aeration, nitrogen or argon atmospheres in the presence of periodate (UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup>), with minor enhancement under aeration for the classical system (UV/TiO<sub>2</sub>). The mineralization of the organic substrate was also monitored. The depletion of organic matter with time was measured using total organic carbon (TOC) analysis. Despite the rapid decolorization of the dye solution in the UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> system, a TOC removal efficiency of ~62% was obtained with both systems after 180 min of treatment. |
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| spelling | doaj.art-e51be4753aa342fb9edd4843db8b10122023-11-24T07:56:25ZengMDPI AGCatalysts2073-43442022-11-011211146010.3390/catal12111460Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and MineralizationMeriem Bendjama0Oualid Hamdaoui1Hamza Ferkous2Abdulaziz Alghyamah3Laboratory of Environmental Engineering, Process Engineering Department, Faculty of Technology, Badji Mokhtar—Annaba University, P.O. Box 12, Annaba 23000, AlgeriaChemical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi ArabiaLaboratory of Environmental Engineering, Process Engineering Department, Faculty of Technology, Badji Mokhtar—Annaba University, P.O. Box 12, Annaba 23000, AlgeriaChemical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi ArabiaHybrid advanced oxidation processes employed to degrade recalcitrant organic pollutants in water have been widely examined in recent years. In the present work, the potential of TiO<sub>2</sub>-mediated photocatalysis in the presence of the periodate anion (IO<sub>4</sub><sup>−</sup>) toward Safranin O (SO) removal from aqueous solutions was investigated. The findings revealed a high efficiency of the UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> system due to the production of more reactive radicals (<sup>•</sup>OH, IO<sub>3</sub><sup>•</sup> and IO<sub>4</sub><sup>•</sup>) and non-radical species (O<sub>3</sub>, IO<sub>3</sub><sup>−</sup> and IO<sub>4</sub><sup>−</sup>). Additionally, the presence of IO<sub>4</sub><sup>−</sup> as an effective electron acceptor avoids electron-hole recombination, which induces more oxidative reactions at the hole level, increasing the degradation rate of SO. Kinetically, the involvement of IO<sub>4</sub><sup>−</sup> anions in the UV/TiO<sub>2</sub> system enhanced substantially the initial rate of degradation; from 0.295 to 12.07 mg L<sup>−1</sup> min<sup>−1</sup>. The performance of both systems, i.e., UV/TiO<sub>2</sub> and UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup>, was examined under different conditions such as initial dye concentration, photocatalyst loading, periodate dosage, initial solution pH, temperature and dissolved gases. The SO degradation was found to be maximized at low concentration of pollutant at the optimum loading of catalyst (0.4 g L<sup>−1</sup>). The continuous increasing in periodate concentration over the range of 0.01–3 mM improved the system reactivity with no overdose effect. Both systems seemed to be insensitive to minor variations in temperature in the range of 15–45 °C, and showed a strong dependence on initial solution pH where the degradation rates increased proportionally with pH values up to pH 10 and decreased afterwards. A slight negative effect on the photocatalytic removal yield was noted under either aeration, nitrogen or argon atmospheres in the presence of periodate (UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup>), with minor enhancement under aeration for the classical system (UV/TiO<sub>2</sub>). The mineralization of the organic substrate was also monitored. The depletion of organic matter with time was measured using total organic carbon (TOC) analysis. Despite the rapid decolorization of the dye solution in the UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> system, a TOC removal efficiency of ~62% was obtained with both systems after 180 min of treatment.https://www.mdpi.com/2073-4344/12/11/1460degradationsafranin OUV/TiO<sub>2</sub> processUV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> processparametric studymineralization |
| spellingShingle | Meriem Bendjama Oualid Hamdaoui Hamza Ferkous Abdulaziz Alghyamah Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization Catalysts degradation safranin O UV/TiO<sub>2</sub> process UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> process parametric study mineralization |
| title | Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization |
| title_full | Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization |
| title_fullStr | Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization |
| title_full_unstemmed | Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization |
| title_short | Degradation of Safranin O in Water by UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> Process: Effect of Operating Conditions and Mineralization |
| title_sort | degradation of safranin o in water by uv tio sub 2 sub io sub 4 sub sup sup process effect of operating conditions and mineralization |
| topic | degradation safranin O UV/TiO<sub>2</sub> process UV/TiO<sub>2</sub>/IO<sub>4</sub><sup>−</sup> process parametric study mineralization |
| url | https://www.mdpi.com/2073-4344/12/11/1460 |
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