Performance of UV/acetylacetone process for saline dye wastewater treatment: Kinetics and mechanism
Futility of traditional advanced oxidation processes (AOPs) in saline wastewater treatment has stimulated the quest for novel “halotolerant” chemical oxidation technology. Acetylacetone (AA) has proven to be a potent photo-activator in the degradation of dyes, but the applicability of UV/AA for sali...
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Veröffentlicht in: | Journal of hazardous materials 2021-03, Vol.406, p.124774, Article 124774 |
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Sprache: | eng |
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Zusammenfassung: | Futility of traditional advanced oxidation processes (AOPs) in saline wastewater treatment has stimulated the quest for novel “halotolerant” chemical oxidation technology. Acetylacetone (AA) has proven to be a potent photo-activator in the degradation of dyes, but the applicability of UV/AA for saline wastewater treatment needs to be verified. In this study, degradation of crystal violet (CV) was investigated in the UV/AA system in the presence of various concentrations of exogenic Cl- or Br-. The results reveal that degradation, mineralization and even accumulation of adsorbable organic halides (AOX) were not significantly affected by the addition of Cl- or Br-. Rates of CV degradation were enhanced by elevating either AA dosage or solution acidity. An apparent kinetic rate equation was developed as r = -d[CV]/dt = k[CV]a[AA]b = (7.34 × 10-4 mM1-(a+b) min-1) × [CV]a=0.16 [AA]b=0.97. In terms of results of radical quenching experiments, direct electron/energy transfer is considered as the major reaction mechanism, while either singlet oxygen or triplet state (3(AA)*) might be involved. Based on identification of degradation byproducts, a possible degradation pathway of CV in the UV/AA system is proposed.
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•The UV/AA process was more effective for CV degradation than the UV/H2O2 process.•UV/AA process had a wider applicability for saline wastewater treatment.•A kinetic rate equation for the CV degradation was developed.•The possible pathway of CV degradation in the UV/AA process was proposed. |
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ISSN: | 0304-3894 1873-3336 |
DOI: | 10.1016/j.jhazmat.2020.124774 |