title: Decomposition byproducts induced by gamma radiation and their toxicity: the case of 2-nitrophenol.
abstract: The induced degradation and detoxification of 2-nitrophenol (2-NP) in aqueous media by gamma irradiation were carefully evaluated in this study. Gamma radiation at absorbed doses as low as 20 kGy was able to degrade 2-NP to reach a removal of at least 85% across the investigated range of concentration (50-150 ppm). 2-NP breaks down to aromatic-based compounds with increasing number of byproducts upon increasing the radiation treatment from the absorbed dose of 50% decomposition (D50) to the absorbed dose of 90% decomposition (D90), after which no byproducts could be detected, indicating the formation of undetectable aliphatic hydrocarbons, insoluble, or volatile byproducts. Toxicology studies showed that the degradation of 2-NP under absorbed doses up to D90resulted in a more toxic byproduct than the parent compound, and a remarkable reduction in the toxicity was observed with the irradiated samples with absorbed doses above D90. Varying the pH of the media to acidic or basic conditions did not significantly alter the degradation behavior of 2-NP. However, a notable improvement of the detoxification was associated with the samples of acidic pH. Adding 0.5% of H2O2to 2-NP solutions had a positive effect by reducing D90by a factor of nine and diminishing the toxicity by twofolds.
authors.affiliation: a National Center for Irradiation Technology, Nuclear Science Research Institute , King Abdulaziz City for Science and Technology , Riyadh , Saudi Arabia.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Alsager
authors.affiliation: a National Center for Irradiation Technology, Nuclear Science Research Institute , King Abdulaziz City for Science and Technology , Riyadh , Saudi Arabia.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Basfar
authors.affiliation: a National Center for Irradiation Technology, Nuclear Science Research Institute , King Abdulaziz City for Science and Technology , Riyadh , Saudi Arabia.
authors.forename: Majid
authors.identifier: http://orcid.org/0000-0002-7870-2681
authors.initials: M
authors.lastname: Muneer
mesh_terms: D005720:Gamma Rays; D006861:Hydrogen Peroxide; D009596:Nitrophenols / Q000737:chemistry* / Q000633:toxicity; D009930:Organic Chemicals
chemical_list: D009596:Nitrophenols; D009930:Organic Chemicals; D006861:Hydrogen Peroxide; C045573:2-nitrophenol
keywords: 2-nitrophenol; Gamma radiation; byproducts and toxicity; detoxification; in-solution degradation