Radiolytic degradation and toxicity changes in γ-irradiated solutions of 2,4-dichlorophenol

Trojanowicz, Marek; Drzewicz, Przemysław; Panta, P.; Głuszewski, Wojciech; Nałęcz‐Jawecki, Grzegorz; Sawicki, J.; Sampa, M.H.O.; Oikawa, Hisashi; Borrely, Sueli Ivone; Czaplicka, Marianna; Szewczyńska, Małgorzata

doi:10.1016/s0969-806x(02)00336-5

Cited by 29 publications

(11 citation statements)

References 37 publications

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“…3 that greater 2-CP degradation was accomplished at pH 4 than at pH 9. These discrepancies can be attributed to the fact that excess chloride ions in acidic media can present additional toxicity to V. fi scheri bacteria and compensate the reduction in 2-CP toxicity [40,41].…”

Section: Effects Of Ph Of Aqueous Solutions On the Toxicity Of 2-cpmentioning

confidence: 99%

Degradation and detoxification of 2-chlorophenol aqueous solutions using ionizing gamma radiation

2017

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Chlorophenols are compounds with high toxicity, poor biodegradability, and carcinogenic and recalcitrant properties. This work studies, for the first time, the destruction and detoxification of 2-chlorophenol (2-CP) in water using 60Co gamma radiation under different conditions including varied radiation doses, addition of hydrogen peroxide (H2O2), and varied pH values. High-performance liquid chromatography (HPLC) and ion chromatography (IC) confirmed a successful degradation of 2-CP to primarily yield phenol molecules and chloride anions. A radiation dose as low as 25 kGy achieved approximately 90% removal of 50–150 ppm of 2-CP in neutral water. However, the addition of a strong oxidizer such as H2O2 to 2-CP solutions reduced the required dose to achieve 90% removal to at least 1.3-fold. The reduction in radiation doses was also observed in acidic and alkaline media, reducing the required doses of 90% removal to at least 0.4-fold. It was imperative to study the toxicity levels of the oxidation by-products to provide directions for the potential applicability of this technology in water treatment. Toxicology Microtox® bioassay indicated a significant reduction in the toxicity of the degradation by-products and the detoxification was further enhanced by the addition of H2O2 and changing the pH to more acidic or alkaline conditions. These findings will contribute to the knowledge of the removal and detoxification of such challenging environmental contaminant and could be potentially applied to other biologically resistant compounds.

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Section: Effects Of Ph Of Aqueous Solutions On the Toxicity Of 2-cpmentioning

confidence: 99%

Degradation and detoxification of 2-chlorophenol aqueous solutions using ionizing gamma radiation

2017

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“…The resulting primary products, that is the high reactive species, together with their yields (G-values) are shown in equation (1) [11,12] : In this study, NaHCO 3 and t-butanol were selected because t-butanol was a typical OH radical scavenger and NaHCO 3 was a common component in water and wastewater. Their reaction with ·OH is as follows [13] : …”

Section: Effect Of Scavengers On 4-cp Degradationmentioning

confidence: 99%

Degradation of 4-chlorophenol in aqueous solution by γ-radiation and ozone oxidation

Wang

Chen

2006

SCI CHINA SER B

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The degradation of 4-chlorophenol (4-CP) by using gamma rays generated by a 60 Co source in the presence of O 3 was investigated. The radiolysis of 4-CP and the kinetics of 4-CP mineralization were analyzed based on the determination of total organic carbon (TOC). The influence of initial 4-CP concentration and the free radicals scavengers (such as NaHCO 3 and t-butanol) on the 4-CP degradation was also studied. The results showed that when the radiation rate was 336 Gy·min −1 , 4-chlorophenol at concentration of 10 mg·L −1 could be completely degraded at the radiation dose of 2 kGy. The degradation of 4-chlorophenol could be described by a first-order reaction model, the rate constant of 4-CP degradation by combined ozonation and radiation was 0.1016 min −1 , which was 2.4 times higher than the sum of radiation (0.0294 min −1 ) and ozonation (0.0137 min −1 ). It revealed that the combination of radiation and ozonation resulted in synergistic effect, which can remarkably increase the degradation efficiency of 4-CP.

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“…Apart from a number of investigations on radiolysis as a purification method, at least four additional ways to utilize ionizing radiation for pollutant destruction in combination with TiO 2 as photocatalyst have been explored (i) The synergy between gamma radiation (radiolysis) and the presence of a catalyst (photocatalysis) [1][2][3][4][5][6][7][8][9]; a similar effect is observed when TiO 2 is applied simultaneously with electron bombardment [10]. Comparative investigation on the effects of UV, gamma and electron irradiation [11] leads to the conclusion that the effect of the catalyst on the pollutant destruction under gammairradiation is negligible, but it enhances its full mineralization.…”

Section: Introductionmentioning

confidence: 99%

Influence of gamma-irradiation on the photocatalytic activity of Degussa P25 TiO2

et al. 2012

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The purpose of this article is to study the influence of gamma irradiation on the sorption capacity and photocatalytic activity of commercially available TiO 2 Degussa P25. The photocatalyst was gamma-irradiated at ambient temperature with doses 8-60 kGy ( 137 Cs, dose rate 2 kGy/24 h) and then stored until analysis/tests in liquid N 2 . X-ray diffraction, SEM, TEM, EPR, and UV-VIS reflectance spectrometry were applied to explore phase composition, crystal cell parameters, crystallite size, textural properties (grain size, and specific surface area), the presence of paramagnetic centers, and UV/VIS absorption of the initial and irradiated samples. The sorption capacity and photocatalytic activity of the products under UVA (17 W, k max = 365 nm) and sunlight irradiation were studied against Malachite Green 10 -5 M aqueous solution, applied as a model pollutant. The sorption capacity varied non-monotonically with the irradiation dose, with clearly expressed maximum and minimum seen at irradiation with doses of 28 and 60 kGy, respectively. The maximum in the photocatalytic activity, both at UV and sunlight illumination, is observed after the dose of 28 kGy is applied; at these conditions, the pollutant degradation rate constant is 1.7/2.7-times higher than the value for the non-irradiated product. The explanation of the obtained results is related mainly to the type and concentration of gamma-generated defects in catalysts, and especially the effect of Ti 3? is discussed. Some of the considered factors may act in opposite directions, causing an extreme point in the relation between the photocatalytic activity and the gamma radiation dose.

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Radiolytic degradation and toxicity changes in γ-irradiated solutions of 2,4-dichlorophenol

Cited by 29 publications

References 37 publications

Degradation and detoxification of 2-chlorophenol aqueous solutions using ionizing gamma radiation

Degradation and detoxification of 2-chlorophenol aqueous solutions using ionizing gamma radiation

Degradation of 4-chlorophenol in aqueous solution by γ-radiation and ozone oxidation

Influence of gamma-irradiation on the photocatalytic activity of Degussa P25 TiO2

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