Effect of initial solution pH on 4-nitrophenol oxidation through homogeneous/heterogeneous photo-Fenton process using goethite/H2O2 system
[Display omitted] •Goethite was used as a heterogeneous catalyst in aqueous phase for the photodegradation of 4-nitrophenol.•A careful study on the effect of pH on the Fenton-like process was carried out.•The relevant role of free radicals was evidenced for the degradation activity.•Goethite (α-FeOO...
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| Published in: | Journal of photochemistry and photobiology. A, Chemistry. Vol. 447; p. 115184 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier B.V
15-01-2024
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | [Display omitted]
•Goethite was used as a heterogeneous catalyst in aqueous phase for the photodegradation of 4-nitrophenol.•A careful study on the effect of pH on the Fenton-like process was carried out.•The relevant role of free radicals was evidenced for the degradation activity.•Goethite (α-FeOOH), hydrogen peroxide and UV irradiation showed to be an efficient catalytic system.•The most promising system promoted a complete abatement of 4-nitrophenol in 60 min, at room temperature.•Goethite proved to be stable and recyclable up to five catalytic cycles.
The photodegradation of 4-nitrophenol (4-NP) through homogeneous/heterogeneous photo-Fenton process was examined in the presence of goethite (α-FeOOH)/H2O2/UV system in solution at different pH values. The degradation of 4-NP was achieved with excellent performance. Conversion reached 100%, 92% and 83% in the first 120 min of irradiation for acidic, point of zero charge (pzc) and weakly alkaline pH, respectively. Meanwhile, 69% of degradation was reached under strong alkaline pH conditions and this resulted in the weakest removal percentage under comparable experimental conditions. The rate of photocatalytic degradation followed pseudo-first order kinetics with kinetic constants of 6.30 × 10−2 min−1, 2.37 × 10−2 min−1, 1.73 × 10−2 min−1 and 0.70 × 10−2 min−1 at pH = 3.0, 5.5, 9.0 and 11.0, respectively. The iron(II) species dissolved in the solution enhanced the photocatalytic degradation and the hydroxyl radicals (OH) production. The involvement of free radicals was evidenced by using scavengers and the results revealed that OH is the main active species. The stability of goethite to repeated uses was investigated too and, after five runs, the removal efficiency of 4-NP was still complete, with values attaining 100%. |
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| ISSN: | 1010-6030 1873-2666 |
| DOI: | 10.1016/j.jphotochem.2023.115184 |