Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with i...Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.展开更多
The photodegradation of persistent and bioaccumulative perftuorooctanoic acid （PFOA） in water by 185 nm vacuum ultraviolet （VUV） light was examined to develop an effective technology to deal with PFOA pollution. P...The photodegradation of persistent and bioaccumulative perftuorooctanoic acid （PFOA） in water by 185 nm vacuum ultraviolet （VUV） light was examined to develop an effective technology to deal with PFOA pollution. PFOA degraded very slowly under irradiation of 254 nm UV light. However, 61.7% of initial PFOA was degraded by 185 nm VUV light within 2 h, and defluorination ratio reached 17.1%. Pseudo first-order-kinetics well simulated its degradation and defluorination. Besides, fluoride ion formed in water, 4 shorter-chain perfluorinated carboxylic acids （PFCAs）, that is, perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, and perfluorobutanoic acid. These were identified as intermediates by LC-MS measurement. These PFCAs consecutively formed and further degraded with irradiation time. According to the mass balance calculation, no other byproducts were formed. It was proposed that PFCAs initially are decarboxylated by 185 nm light, and the radical thus formed reacts with water to form shorter-chain PFCA with one less CF2 unit.展开更多
Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, ...Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, and degradation rates increased with increasing initial p H. Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS, especially hydrated electron. The decomposition efficiencies were 95.7% for PFOA and 85.9% for PFOS, by EB irradiation in an anoxic alkaline solution(p H = 13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH_2 unit were proposed.展开更多
Perfluorooctanoic acid(PFOA)is a widespread synthetic persistent organic pollutant that may enrich along the food chain and affect the growth,development,reproduction,and lipid metabolism of aquatic organisms,particul...Perfluorooctanoic acid(PFOA)is a widespread synthetic persistent organic pollutant that may enrich along the food chain and affect the growth,development,reproduction,and lipid metabolism of aquatic organisms,particularly the benthic organisms.How-ever,the toxic effects of PFOA on the half-smooth tongue sole Cynoglossus semilaevis,a commercial benthic fish in China,have rarely been reported.Because juvenile fish are sensitive to environmental pollutants,in the present study,histological assessment and tran-scriptome sequencing were performed to determine the short-term impact of PFOA on juvenile half-smooth tongue soles.Histologi-cal analysis showed that PFOA exposure caused hepatocyte rupture,intestinal villi breakage,increased goblet cell count,and brain ab-normal.Transcriptome results showed that some interesting signaling pathways,such as glycolysis/gluconeogenesis,PPAR signaling pathway and GABAergic synapse signaling pathway,were enriched after PFOA exposure.In addition,some metabolic,immune and neural genes were differentially expressed,which including ependymin,hbb1-like and gad 1,and they were up-regulated after 14 days of exposure.Transcriptome results also indicated that half-smooth tongue sole might improve energy metabolism in response to PFOA toxicity after 7 days of exposure.These findings provide a basis for studying the ecological effects of PFOA on marine benthic fishes.展开更多
Surfactant doped polyaniline was synthesized in the aqueous solution of aniline and anionic surfactant of perfluorooctanoic acid (PFO) by chemical synthesis using potassium peroxy disulphate as an oxidant by varying t...Surfactant doped polyaniline was synthesized in the aqueous solution of aniline and anionic surfactant of perfluorooctanoic acid (PFO) by chemical synthesis using potassium peroxy disulphate as an oxidant by varying the aniline to surfactant ratio. The solubility of the chemically prepared surfactant doped polyaniline (PANI) was ascertained and it showed good solubility in dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone, acetonitrile, ethanol, aceticacid, trichloroethylene, dichloromethane, tetrahydrofuran, ethylacetate, diethylether, toluene, chloroform and sparingly soluble in n-hexane and water. The prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), UV-visible, X-ray diffraction (XRD), cyclic voltammetric (CV), EIS and scanning electron microscopy (SEM). The analysis of UV-visible and FTIR showed that aniline has been polymerized to PANI in its conducting emeraldine form. FTIR spectra showed that the peaks at 1670, 3315 and 1400 cm-1 corresponded to PFO. FTIR spectra showed that amine peak observed at 1593 cm-1 was shifted to lower wave number due to the interaction between PANI and the surfactant. SEM analysis showed that the variation in morphology of doped PANI was predominantly dependent on the concentration of the surfactant. Elemental analysis was done by energy dispersive spectroscopic (EDAX) which shows the presence of C, N, O, S and F. XRD pattern showed that the formation of nanosized (18 nm) and crystalline polymer. CV studies of the synthesized polymer exhibited good adherent behavior on electrode surface. It exhibited three oxidation peaks at approximately 0.283 V, 0.541 V and 0.989 V and two reduction peaks at 0.1421 and 0.3854 V. Electrical conductivity of PFO doped PANI was studied by impedance spectroscopic method.展开更多
Ultrasonic extraction technique was used to extract perflurooctanoic acid (PFOA) and its salts from fluro-paints.The extract was quantified after filtration and concentration by gas chromatography-mass (GC-MS) method ...Ultrasonic extraction technique was used to extract perflurooctanoic acid (PFOA) and its salts from fluro-paints.The extract was quantified after filtration and concentration by gas chromatography-mass (GC-MS) method using perflurodecanoic acid methyl ester as an internal standard.The GC-MS conditions were: HP-Innowax capillary column; oven temperature,50℃(5 min)30℃/min240℃(5 min); splittless mode; injection volume,1μL; negative chemical ion source,reacting gas,CH4,20%; select ion scan mode (SIM);Line range was 1.0-1.0×105 μg/L; the correlation coefficient was 0.999; the low limit of detection (LOD) was 0.1 μg/L.The RSD was 4.24% and 3.58% respectively for low and high concentration of PFOA,and the average recovery was between 86%-111%.展开更多
文摘Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.
基金Project supported by the National Natural Science Foundation of China (No. 20577026) the New Century Excellent Talents in University (No. NCET-04-0090).
文摘The photodegradation of persistent and bioaccumulative perftuorooctanoic acid （PFOA） in water by 185 nm vacuum ultraviolet （VUV） light was examined to develop an effective technology to deal with PFOA pollution. PFOA degraded very slowly under irradiation of 254 nm UV light. However, 61.7% of initial PFOA was degraded by 185 nm VUV light within 2 h, and defluorination ratio reached 17.1%. Pseudo first-order-kinetics well simulated its degradation and defluorination. Besides, fluoride ion formed in water, 4 shorter-chain perfluorinated carboxylic acids （PFCAs）, that is, perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, and perfluorobutanoic acid. These were identified as intermediates by LC-MS measurement. These PFCAs consecutively formed and further degraded with irradiation time. According to the mass balance calculation, no other byproducts were formed. It was proposed that PFCAs initially are decarboxylated by 185 nm light, and the radical thus formed reacts with water to form shorter-chain PFCA with one less CF2 unit.
基金supported by the National Natural Science Foundation of China(Nos.11675098,41430644,41473090,41373098)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT13078)
文摘Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, and degradation rates increased with increasing initial p H. Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS, especially hydrated electron. The decomposition efficiencies were 95.7% for PFOA and 85.9% for PFOS, by EB irradiation in an anoxic alkaline solution(p H = 13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH_2 unit were proposed.
基金supported by the National Key R&D Program(No.2018YFD0900301-03)the MNR Key Laboratory of Marine Eco-Environmental Science and Technology,China(No.MEEST-2021-04).
文摘Perfluorooctanoic acid(PFOA)is a widespread synthetic persistent organic pollutant that may enrich along the food chain and affect the growth,development,reproduction,and lipid metabolism of aquatic organisms,particularly the benthic organisms.How-ever,the toxic effects of PFOA on the half-smooth tongue sole Cynoglossus semilaevis,a commercial benthic fish in China,have rarely been reported.Because juvenile fish are sensitive to environmental pollutants,in the present study,histological assessment and tran-scriptome sequencing were performed to determine the short-term impact of PFOA on juvenile half-smooth tongue soles.Histologi-cal analysis showed that PFOA exposure caused hepatocyte rupture,intestinal villi breakage,increased goblet cell count,and brain ab-normal.Transcriptome results showed that some interesting signaling pathways,such as glycolysis/gluconeogenesis,PPAR signaling pathway and GABAergic synapse signaling pathway,were enriched after PFOA exposure.In addition,some metabolic,immune and neural genes were differentially expressed,which including ependymin,hbb1-like and gad 1,and they were up-regulated after 14 days of exposure.Transcriptome results also indicated that half-smooth tongue sole might improve energy metabolism in response to PFOA toxicity after 7 days of exposure.These findings provide a basis for studying the ecological effects of PFOA on marine benthic fishes.
文摘Surfactant doped polyaniline was synthesized in the aqueous solution of aniline and anionic surfactant of perfluorooctanoic acid (PFO) by chemical synthesis using potassium peroxy disulphate as an oxidant by varying the aniline to surfactant ratio. The solubility of the chemically prepared surfactant doped polyaniline (PANI) was ascertained and it showed good solubility in dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone, acetonitrile, ethanol, aceticacid, trichloroethylene, dichloromethane, tetrahydrofuran, ethylacetate, diethylether, toluene, chloroform and sparingly soluble in n-hexane and water. The prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), UV-visible, X-ray diffraction (XRD), cyclic voltammetric (CV), EIS and scanning electron microscopy (SEM). The analysis of UV-visible and FTIR showed that aniline has been polymerized to PANI in its conducting emeraldine form. FTIR spectra showed that the peaks at 1670, 3315 and 1400 cm-1 corresponded to PFO. FTIR spectra showed that amine peak observed at 1593 cm-1 was shifted to lower wave number due to the interaction between PANI and the surfactant. SEM analysis showed that the variation in morphology of doped PANI was predominantly dependent on the concentration of the surfactant. Elemental analysis was done by energy dispersive spectroscopic (EDAX) which shows the presence of C, N, O, S and F. XRD pattern showed that the formation of nanosized (18 nm) and crystalline polymer. CV studies of the synthesized polymer exhibited good adherent behavior on electrode surface. It exhibited three oxidation peaks at approximately 0.283 V, 0.541 V and 0.989 V and two reduction peaks at 0.1421 and 0.3854 V. Electrical conductivity of PFO doped PANI was studied by impedance spectroscopic method.
文摘Ultrasonic extraction technique was used to extract perflurooctanoic acid (PFOA) and its salts from fluro-paints.The extract was quantified after filtration and concentration by gas chromatography-mass (GC-MS) method using perflurodecanoic acid methyl ester as an internal standard.The GC-MS conditions were: HP-Innowax capillary column; oven temperature,50℃(5 min)30℃/min240℃(5 min); splittless mode; injection volume,1μL; negative chemical ion source,reacting gas,CH4,20%; select ion scan mode (SIM);Line range was 1.0-1.0×105 μg/L; the correlation coefficient was 0.999; the low limit of detection (LOD) was 0.1 μg/L.The RSD was 4.24% and 3.58% respectively for low and high concentration of PFOA,and the average recovery was between 86%-111%.
