title: Monitoring ecotoxicity of disperse red 1 dye during photo-Fenton degradation.
abstract: The present work assessed the ecotoxicity of the commercially available form of the azo dye Disperse Red 1 (DR1) and the main degradation products generated during photo-Fenton degradation. The acute toxicity tests with the microcrustacean Daphnia similis showed that toxicity increased after 10 min of treatment, when 35% of the original concentration of the dye has been degraded but without decrease in total organic carbon concentration (TOC). The increase of toxicity was a consequence of generation of degradation products of higher toxicity than DR1, which achieved maximum concentration after 10 min reaction. The structures identified using LC/MS indicated that most of the intermediates were formed after addition of hydroxyl radical to benzenic ring but the cleavage of azo bond was also observed. The intermediates were further degraded and toxicity was then reduced to non toxic levels after 45 min experiment, when 98% of the initial concentration of DR1 was degraded and mineralization achieved 55%. The results of this study showed that the textile dye DR1 can be degraded by photo-Fenton process with removal of acute toxicity to D. similis even with incomplete mineralization.
authors: Departamento de Química Analítica, Instituto de Química de Araraquara, UNESP - Univ Estadual Paulista, Araraquara, SP 14801-970, Brazil.
authors: Laís
authors: L
authors: da Silva Leite
authors: Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, USP-SP, São Paulo, SP 05434-070, Brazil; Faculdade de Tecnologia, FT-UNICAMP, Universidade Estadual de Campinas, Limeira, SP 13484-332, Brazil.
authors: Bianca
authors: B
authors: de Souza Maselli
authors: Faculdade de Tecnologia, FT-UNICAMP, Universidade Estadual de Campinas, Limeira, SP 13484-332, Brazil.
authors: Gisela
authors: G
authors: de Aragão Umbuzeiro
authors: Departamento de Química Analítica, Instituto de Química de Araraquara, UNESP - Univ Estadual Paulista, Araraquara, SP 14801-970, Brazil. Electronic address: nogueira@iq.unesp.br.
authors: Raquel F
authors: RF
authors: Pupo Nogueira
mesh_terms: D000818:Animals; D001391:Azo Compounds / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity; D004396:Coloring Agents / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity; D003621:Daphnia / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008027:Light; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity; D018508:Water Purification / Q000379:methods
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; C069318:Disperse Red 1; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Daphnia similis; Degradation products; Disperse dyes; Textile dye