| Texto completo | |
| Autor(es): |
Nunes, Roberta F.
;
Ribeiro, Julio C. O.
;
Carvalho-Silva, Valter H.
;
Dionysiou, Dionysios D.
;
Teixeira, Antonio C. S. C.
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ENVIRONMENTAL TECHNOLOGY; v. N/A, p. 16-pg., 2025-07-01. |
| Resumo | |
Chlorinated phenols are persistent pollutants frequently detected in industrial effluents and contaminated surface waters, posing risks to aquatic ecosystems. Herein, the best initial sulfite concentration [SO32-]0 and initial pH for the degradation of 2,4-dichlorophenol (2,4-DCP) in the presence of sulfite under UVC radiation and oxic conditions are reported. Low sulfite dosages (60-150 mg L-1) were explored to use UVC/sulfite as a pretreatment for persulfate (PS)-based processes. The UVC/persulfate (UVC/PS), UVC/sulfite, and combined UVC/sulfite + PS processes were used for the degradation of 2,4-DCP and 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP). Results have shown that increasing [SO32-]0 up to 60 mg L-1 (pH0 similar to 8.5) has led to higher 2,4-DCP degradations through UVC/sulfite. In contrast, at pH0 values around 3, 5, and 10, direct photolysis of 2,4-DCP and 2,3,4,6-TeCP occurred. Removals of 2,4-DCP and 2,3,4,6-TeCP were improved by the addition of PS after the UVC/sulfite pretreatment, at optimum conditions. Hydroxylation was predominant in the UVC/sulfite + PS system, by improved generation of hydroxyl radicals, in addition to a slightly higher contribution of sulfate radicals. Low molecular weight acids were observed as transformation products for the UVC/sulfite + PS process, due to dechlorination and cleavage of the benzene ring. Finally, according to predictions from the ECOSAR (Ecological Structure-Activity Relationships) program, fewer toxic products were identified for different organisms (fish, daphnids and green algae) in the UVC/sulfite + PS process. This result is important and reinforces that the UVC/sulfite + PS process in the presence of oxygen can lead to lower toxicity of the treated water. (AU) | |
| Processo FAPESP: | 19/24158-9 - Destinação ambiental de poluentes emergentes em águas superficiais e alternativas sustentáveis de mitigação: abordagem híbrida experimental-computacional |
| Beneficiário: | Antonio Carlos Silva Costa Teixeira |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |