title: Role of surfactant derived intermediates in the efficacy and mechanism for radiation chemical degradation of a hydrophobic azo dye, 1-phenylazo-2-naphthol.
abstract: A combined methodology involving gamma and pulse radiolysis, product analysis and toxicity studies has been adopted to comprehend the degradation process of a model hydrophobic azo dye, 1-phenylazo-2-naphthol, emphasizing the role of the surfactant, which is an integral part of textile waste. Two new and important findings are underlined in this article. The first is the direct attestation of the hydrazyl radical-parent adduct, formed in the reaction of the dye with e(-)aq followed by protonation and subsequent addition to the unreacted dye molecule. This has been confirmed from concentration dependent studies. Secondly, we have clearly shown that in the reaction of hydroxyl radical with the dye in Triton X-100 media, the initially produced TX radicals cause reductive degradation of the dye. Identification and detailed analysis of HPLC and GCMS data reveals that similar products are formed in both the reactions of e(-)aq and OH radicals. Moreover, the cytotoxicity of 10(-4)moldm(-3) dye was found to be reduced significantly after irradiation. Thus, the present study not only depicts new pathways for the degradation of hydrophobic azo dye, but also demonstrates the role of a surfactant in the entire process.
authors.affiliation: Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: Laboni
authors.initials: L
authors.lastname: Das
authors.affiliation: Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: Suchandra
authors.initials: S
authors.lastname: Chatterjee
authors.affiliation: Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: Devidas B
authors.initials: DB
authors.lastname: Naik
authors.affiliation: Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India. Electronic address: asoumya@barc.gov.in.
authors.forename: Soumyakanti
authors.initials: S
authors.lastname: Adhikari
mesh_terms: D000818:Animals; D016466:CHO Cells; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents / Q000737:chemistry* / Q000528:radiation effects* / Q000633:toxicity; D006224:Cricetinae; D003412:Cricetulus; D052918:Environmental Restoration and Remediation; D005720:Gamma Rays; D017665:Hydroxyl Radical / Q000737:chemistry; D007220:Industrial Waste; D009284:Naphthols / Q000737:chemistry* / Q000528:radiation effects* / Q000633:toxicity; D017830:Octoxynol; D011522:Protons; D011675:Pulse Radiolysis; D013501:Surface-Active Agents / Q000737:chemistry*; D013783:Textile Industry; D014865:Waste Disposal, Fluid
chemical_list: D004396:Coloring Agents; D007220:Industrial Waste; D009284:Naphthols; D011522:Protons; D013501:Surface-Active Agents; D017665:Hydroxyl Radical; C024336:1-phenylazo-2-naphthol; D017830:Octoxynol
keywords: Hydrazyl radical-parent adduct; Hydrophobic azo dye; New mechanism; Reduced cytotoxicity; Reducing TX-100 radical; Surfactant radical induced degradation