Due to their persistence,bioaccumulation,and resistance to degradation,perfluorinated substances(PFASs)have significant impacts on the environment and human health.This study comprehensively analyzed and assessed the ...Due to their persistence,bioaccumulation,and resistance to degradation,perfluorinated substances(PFASs)have significant impacts on the environment and human health.This study comprehensively analyzed and assessed the occurrence characteristics,sources,and potential ecological risks of 13 PFASs in the Yangtze River.The results indicated that the concentrations ofΣPFASs range from 5.1 to 57.7 ng/L,with more severe pollution downstream and perfluorobutane sulfonate(PFBuS)being the main pollutant.ΣPFASs showed a positive correlation with total organic carbon and absorbance under the condition of UV wavelength 254 nm(UV_(254)),and a negative correlation with total dissolved solids.Positive matrix factorization model analysis revealed that the primary sources of PFASs in the study area are food packaging,the electroplating industry,and the manufacturing and processing of fluoropolymer-containing products.The total ecological risk value of PFASs indicated that the ecological risks to algae,invertebrates,and fish are negligible.The annual load of ΣPFASs in the Yangtze River was 39.00 t,with the highest concentrations of pollutants being PFBuS(26.41 t/year),perfluorobutanoic acid(6.47 t/year),and perfluorooctanoic acid(PFOA,3.19t/year).While PFASs have not yet posed a risk to aquatic organisms,the increase in the use of short-chain PFASs substitutes(C4-C7)due to the regulation of PFOA and perfluorooctane sulfonate highlights the need for continued monitoring of short-chain PFASs pollution.展开更多
[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spect...[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS).[Methods]The samples were first subjected to precipitation of proteins by potassium ferrocyanide solution and zinc acetate solution,and then extracted by acetonitrile and detected by LC-MS/MS.Next,sodium chloride was added,and after vortex centrifugation,the acetonitrile layer was dried by blowing with nitrogen.Subsequently,1 ml of methanol was added to prepare a test solution.An ACQUITY UPLC BEH C18(2.6 m,2.1 mm×100 mm)chromatographic column was used for liquid phase separation,and gradient elution was performed using 10 mmol ammonium acetate solution-acetonitrile as the mobile phase.The MS detection adopted the MRM mode for acquisition,positive and negative ion mode switching for simultaneous determination,and external standard method for quantification.[Results]In the linear ranges of the target substances,the correlation coefficients R^(2)were all greater than 0.99.The detection limits of the method was in the range of 0.001-0.05μg/kg,and the quantitation limits were in the range of 0.03-0.20 ng/L.The recovery values ranged from 72.8%to 110.5%.[Conclusions]This method has high sensitivity and good accuracy,and thus strong practical value.展开更多
A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce ...A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.展开更多
A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films o...A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.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
In this work, a method was developed and optimized for the analysis of polyfluoroalkyl and/or perfluoroalkyl substances（PFASs） content in surface water and sediment samples with high instrumental response and good s...In this work, a method was developed and optimized for the analysis of polyfluoroalkyl and/or perfluoroalkyl substances（PFASs） content in surface water and sediment samples with high instrumental response and good separation. Surface water and sediment samples were collected from the Yangtze River Delta（YRD） to analyze the distribution characteristics of perfluoroalkyl carboxylic acids（PFCAs）, perfluoroalkane sulfonic acids（PFSAs）, perfluoroalkyl phosphonic acids（PFPAs）, perfluoroalkyl phosphinic acids（PFPiAs）, and polyfluoroalkyl phosphoric acid diesters（di PAPs）. The results showed that the total concentrations of PFCAs and PFSAs in YRD varied from 31 to 902 ng/L. PFCAs（≥ 11 carbons） and PFSAs（≥ 10 carbons atoms） were not detected in any surface water samples. The mean concentrations of all PFCAs and PFSAs in surface water from the sampling areas decreased in the following order：Yangtze river（191 ng/L） ≈ Taihu lake（189 ng/L） 〉 Huangpu river（122 ng/L） ≈ Qiantang river（120 ng/L） 〉 Jiaxing urban river（100 ng/L）. Strong significant（p 〈 0.05） correlations between the concentrations of many of the compounds were found in the sampling areas, suggesting a common source for these compounds. Only perfluorooctanoic acid（PFOA） was observed in all sediment samples, at concentrations varying from 0.02 to 1.35 ng/g. Finally, detection rates of two di PAPs were only 8% and 10%, respectively and the concentration of di PAPs was two to three times lower compared to PFCAs and PFSAs.展开更多
Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many stud...Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many studies have focused on two of the most representative PFASs, PFOS and PFOA, the potential toxicity of short-chain PFASs has not yet been given sufficient attention.We used a battery of assays to evaluate the toxicity of several four-carbon and six-carbon perfluorinated sulfonates and carboxyl acids(PFBS,PFHxS, PFBA and PFHxA), with a human mesenchymal stem cell(hMSC) system.Our results demonstrate significant cyto-and potential developmental toxicity for all the compounds analyzed, with shared but also distinct mechanisms of toxicity.Moreover, the effects of PFBS and PFHxS were stronger than those of PFBA and PFHxA, but occurred at higher doses compared to PFOS or PFOA.展开更多
12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS）...12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS） and perfluorooctanoate（PFOA） were the most prominent PFCs, with average concentrations of 5.73 mg/L and 5.46 mg/L for textile workers, and 2.55 mg/L and 2.84 mg/L for barbers.PFOS and perfluorohexanesulfonate（PFHxS） concentrations revealed a positive correlation in blood samples（p 〈 0.01）, and concentrations among PFOS, perfluorononanoic acid（PFNA） and perfluorodecanoic acid（PFDA） also revealed positive correlations（p 〈 0.01）. The influence of gender and age on PFC concentration in blood was also investigated, and the results showed that there was no statistically significant difference between the male and female samples, as well as in samples from people with different ages. Generally speaking, the textile workers展开更多
The changes of crosslinking network of perfluorinated elastomer(FFKM)cured by TAIC and DBPH under thermo-oxidative aging conditions were investigated.Two competitive processes including post-curing and network destruc...The changes of crosslinking network of perfluorinated elastomer(FFKM)cured by TAIC and DBPH under thermo-oxidative aging conditions were investigated.Two competitive processes including post-curing and network destruction occur simultaneously,which directly affect the storage modulus and crosslinking density.With the increase of aging temperature,the network destruction becomes dominant.FTIR and XPS characterizations further reveal that the network destruction happens preferentially on the crosslink points of TAIC structure,and the post-curing is mainly caused by the decomposition of residual curing agent DBPH.Unlike the easier breaking of TAIC structure in the crosslinking network,both the backbone and the pendent groups of FFKM itself are much more stable.To further figure out the destruction mechanism,TGAFTIR-GC-MS test was also conducted and a schematic degradation process of TAIC structure was proposed.It is found that the destruction of TAIC crosslinking points happens first on the unstable exocyclic C―N bonds and the intermediate ring radicals could eventually decompose into volatile hydrogen isocyanate(HCNO)under extreme condition.展开更多
Heavy metals,polycyclic aromatic hydrocarbons(PAHs),and perfluorinated alkyl substances(PFASs)polluted in 155 samples of two marine crustaceans(Oratosquilla oratoria and Portunus trituberculatus)harvested in the Zhous...Heavy metals,polycyclic aromatic hydrocarbons(PAHs),and perfluorinated alkyl substances(PFASs)polluted in 155 samples of two marine crustaceans(Oratosquilla oratoria and Portunus trituberculatus)harvested in the Zhoushan fishing ground in the East China Sea were assessed.The results showed that Pb,Hg,and iAs in the whole edible parts of O.oratoria and P.trituberculatus were at trace levels,far below the limits set by the China’s national standard,whereas the exceeding standard rates of Cd in the whole edible parts of O.oratoria and P.trituberculatus were 98.6%and 75.6%,respectively.Moreover,the average Cd levels and the exceeding standard rates of Cd in the visceral tissues of O.oratoria were significantly higher than those in the muscle tissues(4.64 mg kg^(−1)vs.0.49 mg kg^(−1)and 96.7%vs 30%,respectively).PAHs with high detection frequency in the two marine crustaceans included NA,AC,FL,and PHE.Total contents of 15 PAHs(abbreviated asΣ15 PAHs)in whole edible parts of O.oratoria and P.trituberculatus were 10.75–65.9μg kg^(−1)(mean=18.7μg kg^(−1)and 13.26–181μg kg^(−1)(mean=24.2μg kg^(−1),and those in the muscle and the visceral tissues of P.trituberculatus were 9.58–160μg kg^(−1)(mean=21.1μg kg^(−1)and 18.22–201μg kg^(−1)(mean=32.7μg kg^(−1),respectively.Furthermore,PFASs that were found at high contents included PFOA,PFOS,and PFOSA,and total contents of 23 PFASs(Σ23 PFASs)ranged 0.0162–5.104μg kg^(−1)(mean=0.915μg kg^(−1).Collectively,the present work provides new data on the contamination in two marine crustaceans captured in the Zhoushan fishing ground in the China East Sea,which can be useful for making suggestions on proper consumption amounts of the two marine crustaceans.展开更多
Perfluorinated alkyl silicone oil （PFASO） was successfully synthesized from N-ethyl-N- hydroxylethyl perfluorinated octane sulfonamide, succinie anhydride and amino silicone oil by esterification and amide reaction ...Perfluorinated alkyl silicone oil （PFASO） was successfully synthesized from N-ethyl-N- hydroxylethyl perfluorinated octane sulfonamide, succinie anhydride and amino silicone oil by esterification and amide reaction at moderate temperature in the presence of different catalysts. The chemical structure of the synthesized samples was characterized by Fourier transform infrared spectroscopy （FT-IR）, the relative molecular mass（MM） and molecular mass distribution（MMD） of PFASO were tested by gel filtration chromatography（GFC）. A commercial epoxy resin （DGEBA） was modified with PFASO, with the content of PFASO 1-5 phr. Thermo-gravimetric analysis （TGA）, impact tests, scanning electron microscope （SEM） and water contact angle test were applied to provide accurate results on the thermal stability, toughness and hydrophobicity of PFASO/epoxy complex. The experimental results reveal that epoxy resins can be successfully modified by adding a small amount of as-synthesized modifiers via simple direct mixing, and verify that the as-synthesized modifier can improve the toughness and hydrophobicity of epoxy resin without sacrificing its thermal properties.展开更多
Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labe...Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.展开更多
Environmental contamination resulting from the production or release of harmful chemicals can lead to negative consequences for wildlife and human health. Perfluorinated alkyl acids（PFAAs） were historically produced...Environmental contamination resulting from the production or release of harmful chemicals can lead to negative consequences for wildlife and human health. Perfluorinated alkyl acids（PFAAs） were historically produced as protective coatings for many household items and currently persist in the environment, wildlife, and humans. PFAAs have been linked to immune suppression, endocrine disruption, and developmental toxicity in wildlife and laboratory studies. This study examines the American alligator, Alligator mississippiensis,as an important indicator of ecosystem contamination and a potential pathway for PFAA exposure in humans. Alligator meat harvested in the 2015 South Carolina（SC） public hunt season and prepared for human consumption was collected and analyzed for PFAAs to determine meat concentrations and relationships with animal body size（total length）, sex, and location of harvest. Of the 15 PFAAs analyzed, perfluorooctane sulfonate（PFOS） was found in all alligator meat samples and at the highest concentrations（median 6.73 ng/g）. No relationship was found between PFAA concentrations and total length or sex.Concentrations of one or all compounds varied significantly across sampling locations, with alligators harvested in the Middle Coastal hunt unit having the highest PFOS concentrations（median 16.0 ng/g; p = 0.0001）. Alligators harvested specifically from Berkley County, SC（located in the Middle Coastal hunt unit） had the highest PFOS concentrations and the greatest number of PFAAs detected（p 〈 0.0001）. The site-specific nature of PFAA concentrations in alligator meat observed in this study suggests a source of PFAA contamination in Berkley County, SC.展开更多
The reference values of serum perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) concentrations were evaluated based on the human blood samples collected from Kashi, Xinjiang. And human serum samples of fa...The reference values of serum perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) concentrations were evaluated based on the human blood samples collected from Kashi, Xinjiang. And human serum samples of family members from Liaoning were evaluated for levels of PFOS and PFOA with the purpose to compare exposure pathways for family members. Among the 110 blood specimens from Kashi, the detection frequency of PFOS and PFOA was 93% and 6%, respectively. Reference values of serum PFOS, evaluated as the 90th percentiles of the concentrations, were determined to be 6.44 μg/L. Significant positive correlations were observed for serum levels of PFOS and PFOA among family members in Liaoning. Specially, stronger correlation between mother and offspring was observed than that between father and offspring. And stronger correlation of serum PFOS and PFOA levels was observed among fam- ily members in rural areas than those in big and small-medium cities. Difference in the association of serum PFOS and PFOA level among family members suggested that exposure in the outdoor and working environment of different oc- cupations should be evaluated. Present study provides reference values for exposure assessment in China and potential pathways of human exposure to PFOS and PFOA.展开更多
2-Cetyl-3-20 keto acid（N-ethyl perfluorinated octyl sulfonamide） N-ethyl ester was synthesized by the reaction of N-ethyl-N-hydroxyethyl perfluorinated octyl sulfonamide and alky ketene dimer. The experimental resul...2-Cetyl-3-20 keto acid（N-ethyl perfluorinated octyl sulfonamide） N-ethyl ester was synthesized by the reaction of N-ethyl-N-hydroxyethyl perfluorinated octyl sulfonamide and alky ketene dimer. The experimental results show that the yield of products can be 89% when the molar ratio of perfluorinated octyl sulfonamide to ketene dimer is 1 ： 1.1 and the reaction lasts about four hours at 80 ℃. The structure of the product was characterized by FTIR and ^1HNMR. The product can dissolve in polar solvents such as NMP, DMAC, THF, DMSO, CHCl3, and 10% weight-loss temperature measured by TGA is 202℃.展开更多
Perfluorooctanoic acid （PFOA）, a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by...Perfluorooctanoic acid （PFOA）, a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by 185 nm vacuum ultraviolet （VUV） is one of the efficient methods for PFOA decomposition. The effects of pH on PFOA decomposition in nitrogen atmosphere or oxygen atmosphere were investigated. At its original pH （4.5） of PFOA aqueous solution, PFOA decomposed efficiently both in nitrogen and in oxygen atmosphere. However, when the pH increased to 12.0, PFOA decomposition was greatly inhibited in oxygen atmosphere, while it was greatly accelerated in nitrogen atmosphere with a very short half-life time （9 rain）. Furthermore, fluorine atoms originally contained in PFOA molecules were almost completely transformed into fluoride ions. Two decomposi- tion pathways have been proposed to explain the PFOA decomposition under different conditions. In acidic and neutral solutions, PFOA predominantly decomposes via the direct photolysis in both atmospheres; while in the alkaline solution and in the absence of oxygen, the decomposition of PFOA is mainly induced by hydrated electrons.展开更多
Li-ion batteries with solid polymer electrolytes(SPEs)are safer than conventional liquid electrolytes due to the absence of highly flammable liquid electrolytes.However,their performance is limited by the poor Li+tran...Li-ion batteries with solid polymer electrolytes(SPEs)are safer than conventional liquid electrolytes due to the absence of highly flammable liquid electrolytes.However,their performance is limited by the poor Li+transport in SPEs at room temperature.Anion-containing polymer-chains incorporated SPEs(ASPEs)are therefore developed to enhance Li^(+) diffusion kinetics.Herein,we propose a novel and feasible strategy to incorporate the anion-containing polymer-chains,such as lithiated perfluorinated sulfonic acid(PFSA),into polyvinylidene fluoride(PVDF)polymer-based SPEs.The immobile anion groups from the PFSA-chains impede the migration of mobile anion groups dissociated from the Li salt.The transference number is thus raised from∼0.3 to 0.52 with the introduction of anion-containing polymer-chains into SPEs.The electrostatic repulsion among anion-containing chains also reduces the close chain stacking and brings 159%increase in the ionic conductivity to 0.83×10^(−3) S/cm at 30℃ in contrast with the pure PVDF-based SPE.In addition,LiFeO_(4)/Li batteries with ASPEs exhibit 55%capacity boost at 0.5 C in contrast to the capacity of batteries with pure-PVDF SPEs,and also offer more than 1000 charge/discharge cycles.Our research findings potentially offer a facile strategy to design thermal stable SPEs with superior Li^(+) transport behaviors towards developing high-performance SPEs-based batteries.展开更多
A fluoride-containing organic silane was synthesized by the reaction of N-ethyl- N-hydroxy-etbyl perfluorinated octyl sulfonamide （EHPOS）, N-（β-aminoethyl）-γ-aminopropyl trimethoxy silane （ATS） and cis-butened...A fluoride-containing organic silane was synthesized by the reaction of N-ethyl- N-hydroxy-etbyl perfluorinated octyl sulfonamide （EHPOS）, N-（β-aminoethyl）-γ-aminopropyl trimethoxy silane （ATS） and cis-butenedioic anhydride （CA）. The experimental results show that the yield of product is up to 87% when the molar ratio ofEHPOS ： CA ： ATS is 1 ： 1.05 ： 1.1. EHPOS and CA were maintained at 115 ℃ for 3 hours, then after cooling the reaction solution to 75 ℃, ATS was added and reacted for another 3.5 hours at 145 ℃. The structure of the product and thermal properties were characterized by Fourier transform infrared （FTIR） and thermogravimetric analysis （TGA）, respectively. Results show that fluoride-containing organic silane has excellent thermal stability below 185℃.展开更多
The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of ph...The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.展开更多
Perfluorinated acids(PFAs)are a new class of persistent organic pollutants that are difficult to defluorinate or remove.The reductive degradation of various representative PFAs in a biomimetic system composed of vitam...Perfluorinated acids(PFAs)are a new class of persistent organic pollutants that are difficult to defluorinate or remove.The reductive degradation of various representative PFAs in a biomimetic system composed of vitamin B_(12)(VB_(12))as a catalyst and nano-zero-valent iron-nickel bimetal(nFe^(0)/Ni^(0))as a reductant was investigated in this study.The effects of the self-structures of PFAs and the coexisting substances in natural water were also discussed.The results indicated that the defluorination and removal rates of PFAs were highly dependent on the length and terminal functional groups of the perfluorocarbon chain.Only Perfluorocarboxylates with C>11 and Perfluorosulfonates with C>6 were significantly degraded.Based on the analysis of the degradation products of perfluorobutanesulfonate(PFBS),perfluorohexanesulfonate(PFHxS),prefluorooctanesulfonate(PFOS),and 2-perfluoroctyl ethanol(8:2 FTOH),hydrolysis followed by the scission of C–S or C–C connecting the terminal functional groups was the dominant degradation pathway of long-chain PFAs instead of cleavage of C–C in the perfluorocarbon chain.The perfluorocarbon chain length affects the product type.It is speculated that the high bond dissociation energies of C–F bonds in short-chain PFAs hinder the occurrence of the decarboxylation-hydroxylation-elimination-hydrolysis(DHEH)pathway and make the addition of(–CF_(2)–)_(n) dominant.Meanwhile,the inhibition of SO_(4)^(2–)removal by PFOS was significant,whereas humic acid,Cl–,and dissolved oxygen had only a slight influence.Overall,this study provides new insights on the degradation of PFAs containing multiple structures and highlights the impact of the self-structure on PFAs removal.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0750000)the National Natural Science Foundation of China(Nos.52270012 and 52470018)the Ministry of Science and Technology of China(Nos.2022YFC3203705 and2021YFC3200904)。
文摘Due to their persistence,bioaccumulation,and resistance to degradation,perfluorinated substances(PFASs)have significant impacts on the environment and human health.This study comprehensively analyzed and assessed the occurrence characteristics,sources,and potential ecological risks of 13 PFASs in the Yangtze River.The results indicated that the concentrations ofΣPFASs range from 5.1 to 57.7 ng/L,with more severe pollution downstream and perfluorobutane sulfonate(PFBuS)being the main pollutant.ΣPFASs showed a positive correlation with total organic carbon and absorbance under the condition of UV wavelength 254 nm(UV_(254)),and a negative correlation with total dissolved solids.Positive matrix factorization model analysis revealed that the primary sources of PFASs in the study area are food packaging,the electroplating industry,and the manufacturing and processing of fluoropolymer-containing products.The total ecological risk value of PFASs indicated that the ecological risks to algae,invertebrates,and fish are negligible.The annual load of ΣPFASs in the Yangtze River was 39.00 t,with the highest concentrations of pollutants being PFBuS(26.41 t/year),perfluorobutanoic acid(6.47 t/year),and perfluorooctanoic acid(PFOA,3.19t/year).While PFASs have not yet posed a risk to aquatic organisms,the increase in the use of short-chain PFASs substitutes(C4-C7)due to the regulation of PFOA and perfluorooctane sulfonate highlights the need for continued monitoring of short-chain PFASs pollution.
基金Supported by Natural Science Foundation of Hunan Province(2024JJ8266).
文摘[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS).[Methods]The samples were first subjected to precipitation of proteins by potassium ferrocyanide solution and zinc acetate solution,and then extracted by acetonitrile and detected by LC-MS/MS.Next,sodium chloride was added,and after vortex centrifugation,the acetonitrile layer was dried by blowing with nitrogen.Subsequently,1 ml of methanol was added to prepare a test solution.An ACQUITY UPLC BEH C18(2.6 m,2.1 mm×100 mm)chromatographic column was used for liquid phase separation,and gradient elution was performed using 10 mmol ammonium acetate solution-acetonitrile as the mobile phase.The MS detection adopted the MRM mode for acquisition,positive and negative ion mode switching for simultaneous determination,and external standard method for quantification.[Results]In the linear ranges of the target substances,the correlation coefficients R^(2)were all greater than 0.99.The detection limits of the method was in the range of 0.001-0.05μg/kg,and the quantitation limits were in the range of 0.03-0.20 ng/L.The recovery values ranged from 72.8%to 110.5%.[Conclusions]This method has high sensitivity and good accuracy,and thus strong practical value.
基金supported by the NQI Project of National key R&D Program of China (No.2016YFF0201102)the project for the“Development of analytical method and certified reference materials for tracing air pollutant source” (No.21AKY1514)from the National Institute of Metrology,Beijing,China。
文摘A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.
文摘A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.
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 Water Pollution Control and Management Program (2014ZX07405001)Drinking Water Source Environmental Monitoring Project (1441100022)
文摘In this work, a method was developed and optimized for the analysis of polyfluoroalkyl and/or perfluoroalkyl substances（PFASs） content in surface water and sediment samples with high instrumental response and good separation. Surface water and sediment samples were collected from the Yangtze River Delta（YRD） to analyze the distribution characteristics of perfluoroalkyl carboxylic acids（PFCAs）, perfluoroalkane sulfonic acids（PFSAs）, perfluoroalkyl phosphonic acids（PFPAs）, perfluoroalkyl phosphinic acids（PFPiAs）, and polyfluoroalkyl phosphoric acid diesters（di PAPs）. The results showed that the total concentrations of PFCAs and PFSAs in YRD varied from 31 to 902 ng/L. PFCAs（≥ 11 carbons） and PFSAs（≥ 10 carbons atoms） were not detected in any surface water samples. The mean concentrations of all PFCAs and PFSAs in surface water from the sampling areas decreased in the following order：Yangtze river（191 ng/L） ≈ Taihu lake（189 ng/L） 〉 Huangpu river（122 ng/L） ≈ Qiantang river（120 ng/L） 〉 Jiaxing urban river（100 ng/L）. Strong significant（p 〈 0.05） correlations between the concentrations of many of the compounds were found in the sampling areas, suggesting a common source for these compounds. Only perfluorooctanoic acid（PFOA） was observed in all sediment samples, at concentrations varying from 0.02 to 1.35 ng/g. Finally, detection rates of two di PAPs were only 8% and 10%, respectively and the concentration of di PAPs was two to three times lower compared to PFCAs and PFSAs.
基金supported by the National Natural Science Foundation of China (Nos.21876197, 21577166, 21707160)the Chinese Academy of Sciences (Nos.XDB14040301, 29[2015]30, QYZDJ-SSW-DQC017)the K.C.Wong Education Foundation.
文摘Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many studies have focused on two of the most representative PFASs, PFOS and PFOA, the potential toxicity of short-chain PFASs has not yet been given sufficient attention.We used a battery of assays to evaluate the toxicity of several four-carbon and six-carbon perfluorinated sulfonates and carboxyl acids(PFBS,PFHxS, PFBA and PFHxA), with a human mesenchymal stem cell(hMSC) system.Our results demonstrate significant cyto-and potential developmental toxicity for all the compounds analyzed, with shared but also distinct mechanisms of toxicity.Moreover, the effects of PFBS and PFHxS were stronger than those of PFBA and PFHxA, but occurred at higher doses compared to PFOS or PFOA.
基金supported by the National Natural Science Foundation of China (Nos. 41023005, 21377145, 21321004)the State Environmental Protection Welfare Scientific Research Project (No. 201009026)
文摘12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS） and perfluorooctanoate（PFOA） were the most prominent PFCs, with average concentrations of 5.73 mg/L and 5.46 mg/L for textile workers, and 2.55 mg/L and 2.84 mg/L for barbers.PFOS and perfluorohexanesulfonate（PFHxS） concentrations revealed a positive correlation in blood samples（p 〈 0.01）, and concentrations among PFOS, perfluorononanoic acid（PFNA） and perfluorodecanoic acid（PFDA） also revealed positive correlations（p 〈 0.01）. The influence of gender and age on PFC concentration in blood was also investigated, and the results showed that there was no statistically significant difference between the male and female samples, as well as in samples from people with different ages. Generally speaking, the textile workers
基金financial support from the National Natural Science Foundation of China (No. 51721091)the financial supports from the National Natural Science Foundation of China (Nos. 51873125 and 52073184)Research Foundation (International Program) of Science and Technology Department of Sichuan Province (No. 2019YFH0027)
文摘The changes of crosslinking network of perfluorinated elastomer(FFKM)cured by TAIC and DBPH under thermo-oxidative aging conditions were investigated.Two competitive processes including post-curing and network destruction occur simultaneously,which directly affect the storage modulus and crosslinking density.With the increase of aging temperature,the network destruction becomes dominant.FTIR and XPS characterizations further reveal that the network destruction happens preferentially on the crosslink points of TAIC structure,and the post-curing is mainly caused by the decomposition of residual curing agent DBPH.Unlike the easier breaking of TAIC structure in the crosslinking network,both the backbone and the pendent groups of FFKM itself are much more stable.To further figure out the destruction mechanism,TGAFTIR-GC-MS test was also conducted and a schematic degradation process of TAIC structure was proposed.It is found that the destruction of TAIC crosslinking points happens first on the unstable exocyclic C―N bonds and the intermediate ring radicals could eventually decompose into volatile hydrogen isocyanate(HCNO)under extreme condition.
基金the National Key R&D Program of China(No.2020YFD0900900)the Public Interest Science and Technology Plan of Ningbo(No.2019C10007)the Basic Public Welfare Project of Zhejiang Provincial Department of Science and Technol ogy(No.LGN20C200015).
文摘Heavy metals,polycyclic aromatic hydrocarbons(PAHs),and perfluorinated alkyl substances(PFASs)polluted in 155 samples of two marine crustaceans(Oratosquilla oratoria and Portunus trituberculatus)harvested in the Zhoushan fishing ground in the East China Sea were assessed.The results showed that Pb,Hg,and iAs in the whole edible parts of O.oratoria and P.trituberculatus were at trace levels,far below the limits set by the China’s national standard,whereas the exceeding standard rates of Cd in the whole edible parts of O.oratoria and P.trituberculatus were 98.6%and 75.6%,respectively.Moreover,the average Cd levels and the exceeding standard rates of Cd in the visceral tissues of O.oratoria were significantly higher than those in the muscle tissues(4.64 mg kg^(−1)vs.0.49 mg kg^(−1)and 96.7%vs 30%,respectively).PAHs with high detection frequency in the two marine crustaceans included NA,AC,FL,and PHE.Total contents of 15 PAHs(abbreviated asΣ15 PAHs)in whole edible parts of O.oratoria and P.trituberculatus were 10.75–65.9μg kg^(−1)(mean=18.7μg kg^(−1)and 13.26–181μg kg^(−1)(mean=24.2μg kg^(−1),and those in the muscle and the visceral tissues of P.trituberculatus were 9.58–160μg kg^(−1)(mean=21.1μg kg^(−1)and 18.22–201μg kg^(−1)(mean=32.7μg kg^(−1),respectively.Furthermore,PFASs that were found at high contents included PFOA,PFOS,and PFOSA,and total contents of 23 PFASs(Σ23 PFASs)ranged 0.0162–5.104μg kg^(−1)(mean=0.915μg kg^(−1).Collectively,the present work provides new data on the contamination in two marine crustaceans captured in the Zhoushan fishing ground in the China East Sea,which can be useful for making suggestions on proper consumption amounts of the two marine crustaceans.
基金Funded by the National High Technology Research and Development Program("863"Program)(No.2003AA305071)
文摘Perfluorinated alkyl silicone oil （PFASO） was successfully synthesized from N-ethyl-N- hydroxylethyl perfluorinated octane sulfonamide, succinie anhydride and amino silicone oil by esterification and amide reaction at moderate temperature in the presence of different catalysts. The chemical structure of the synthesized samples was characterized by Fourier transform infrared spectroscopy （FT-IR）, the relative molecular mass（MM） and molecular mass distribution（MMD） of PFASO were tested by gel filtration chromatography（GFC）. A commercial epoxy resin （DGEBA） was modified with PFASO, with the content of PFASO 1-5 phr. Thermo-gravimetric analysis （TGA）, impact tests, scanning electron microscope （SEM） and water contact angle test were applied to provide accurate results on the thermal stability, toughness and hydrophobicity of PFASO/epoxy complex. The experimental results reveal that epoxy resins can be successfully modified by adding a small amount of as-synthesized modifiers via simple direct mixing, and verify that the as-synthesized modifier can improve the toughness and hydrophobicity of epoxy resin without sacrificing its thermal properties.
基金Foundation item: Projects(51108197, 51205215) supported by the National Natural Science Foundation of ChinaProjects(2011J05135, 2011J01318) supported by the Natural Science Foundation of Fujian Province, China+1 种基金Project(11QZR08) supported by the Scientific Research Foundation of Overseas Chinese Affairs Office of the State Council,ChinaProject(10BS213) supported by the Scientific Research Foundation for Advanced Talents,Huaqiao University,China
文摘Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.
基金the Graduate School at the College of Charlestonrepresents Technical Contribution No.6542 of the Clemson University Experiment Station
文摘Environmental contamination resulting from the production or release of harmful chemicals can lead to negative consequences for wildlife and human health. Perfluorinated alkyl acids（PFAAs） were historically produced as protective coatings for many household items and currently persist in the environment, wildlife, and humans. PFAAs have been linked to immune suppression, endocrine disruption, and developmental toxicity in wildlife and laboratory studies. This study examines the American alligator, Alligator mississippiensis,as an important indicator of ecosystem contamination and a potential pathway for PFAA exposure in humans. Alligator meat harvested in the 2015 South Carolina（SC） public hunt season and prepared for human consumption was collected and analyzed for PFAAs to determine meat concentrations and relationships with animal body size（total length）, sex, and location of harvest. Of the 15 PFAAs analyzed, perfluorooctane sulfonate（PFOS） was found in all alligator meat samples and at the highest concentrations（median 6.73 ng/g）. No relationship was found between PFAA concentrations and total length or sex.Concentrations of one or all compounds varied significantly across sampling locations, with alligators harvested in the Middle Coastal hunt unit having the highest PFOS concentrations（median 16.0 ng/g; p = 0.0001）. Alligators harvested specifically from Berkley County, SC（located in the Middle Coastal hunt unit） had the highest PFOS concentrations and the greatest number of PFAAs detected（p 〈 0.0001）. The site-specific nature of PFAA concentrations in alligator meat observed in this study suggests a source of PFAA contamination in Berkley County, SC.
文摘The reference values of serum perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) concentrations were evaluated based on the human blood samples collected from Kashi, Xinjiang. And human serum samples of family members from Liaoning were evaluated for levels of PFOS and PFOA with the purpose to compare exposure pathways for family members. Among the 110 blood specimens from Kashi, the detection frequency of PFOS and PFOA was 93% and 6%, respectively. Reference values of serum PFOS, evaluated as the 90th percentiles of the concentrations, were determined to be 6.44 μg/L. Significant positive correlations were observed for serum levels of PFOS and PFOA among family members in Liaoning. Specially, stronger correlation between mother and offspring was observed than that between father and offspring. And stronger correlation of serum PFOS and PFOA levels was observed among fam- ily members in rural areas than those in big and small-medium cities. Difference in the association of serum PFOS and PFOA level among family members suggested that exposure in the outdoor and working environment of different oc- cupations should be evaluated. Present study provides reference values for exposure assessment in China and potential pathways of human exposure to PFOS and PFOA.
基金Funded by the National High-Tech Foundation(No. 2003 AA305920)
文摘2-Cetyl-3-20 keto acid（N-ethyl perfluorinated octyl sulfonamide） N-ethyl ester was synthesized by the reaction of N-ethyl-N-hydroxyethyl perfluorinated octyl sulfonamide and alky ketene dimer. The experimental results show that the yield of products can be 89% when the molar ratio of perfluorinated octyl sulfonamide to ketene dimer is 1 ： 1.1 and the reaction lasts about four hours at 80 ℃. The structure of the product was characterized by FTIR and ^1HNMR. The product can dissolve in polar solvents such as NMP, DMAC, THF, DMSO, CHCl3, and 10% weight-loss temperature measured by TGA is 202℃.
基金supported by the National Basic Research Program (973) of China (No. 2013CB632403)the National Natural Science Foundation (Nos. 21267006, 21221004)+1 种基金the Tsinghua University Initiative Scientific Research Program No. 20131089251the Collaborative Innovation Center for Regional Environmental Quality
文摘Perfluorooctanoic acid （PFOA）, a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by 185 nm vacuum ultraviolet （VUV） is one of the efficient methods for PFOA decomposition. The effects of pH on PFOA decomposition in nitrogen atmosphere or oxygen atmosphere were investigated. At its original pH （4.5） of PFOA aqueous solution, PFOA decomposed efficiently both in nitrogen and in oxygen atmosphere. However, when the pH increased to 12.0, PFOA decomposition was greatly inhibited in oxygen atmosphere, while it was greatly accelerated in nitrogen atmosphere with a very short half-life time （9 rain）. Furthermore, fluorine atoms originally contained in PFOA molecules were almost completely transformed into fluoride ions. Two decomposi- tion pathways have been proposed to explain the PFOA decomposition under different conditions. In acidic and neutral solutions, PFOA predominantly decomposes via the direct photolysis in both atmospheres; while in the alkaline solution and in the absence of oxygen, the decomposition of PFOA is mainly induced by hydrated electrons.
基金supported by the National Natural Science Foundation of China(Nos.51972043 and 52102212)the Sichuan-Hong Kong Collaborative Research Fund(No.2021YFH0184)+1 种基金the Foundation of Yangtze Delta Region Institute(Huzhou)of UESTC,China(Nos.U03210010 and U03210028)Huzhou Science and Technology Special Representative Project(No.2021KT54).
文摘Li-ion batteries with solid polymer electrolytes(SPEs)are safer than conventional liquid electrolytes due to the absence of highly flammable liquid electrolytes.However,their performance is limited by the poor Li+transport in SPEs at room temperature.Anion-containing polymer-chains incorporated SPEs(ASPEs)are therefore developed to enhance Li^(+) diffusion kinetics.Herein,we propose a novel and feasible strategy to incorporate the anion-containing polymer-chains,such as lithiated perfluorinated sulfonic acid(PFSA),into polyvinylidene fluoride(PVDF)polymer-based SPEs.The immobile anion groups from the PFSA-chains impede the migration of mobile anion groups dissociated from the Li salt.The transference number is thus raised from∼0.3 to 0.52 with the introduction of anion-containing polymer-chains into SPEs.The electrostatic repulsion among anion-containing chains also reduces the close chain stacking and brings 159%increase in the ionic conductivity to 0.83×10^(−3) S/cm at 30℃ in contrast with the pure PVDF-based SPE.In addition,LiFeO_(4)/Li batteries with ASPEs exhibit 55%capacity boost at 0.5 C in contrast to the capacity of batteries with pure-PVDF SPEs,and also offer more than 1000 charge/discharge cycles.Our research findings potentially offer a facile strategy to design thermal stable SPEs with superior Li^(+) transport behaviors towards developing high-performance SPEs-based batteries.
基金Funded by the Military Defense Project (No. 200701HX03)
文摘A fluoride-containing organic silane was synthesized by the reaction of N-ethyl- N-hydroxy-etbyl perfluorinated octyl sulfonamide （EHPOS）, N-（β-aminoethyl）-γ-aminopropyl trimethoxy silane （ATS） and cis-butenedioic anhydride （CA）. The experimental results show that the yield of product is up to 87% when the molar ratio ofEHPOS ： CA ： ATS is 1 ： 1.05 ： 1.1. EHPOS and CA were maintained at 115 ℃ for 3 hours, then after cooling the reaction solution to 75 ℃, ATS was added and reacted for another 3.5 hours at 145 ℃. The structure of the product and thermal properties were characterized by Fourier transform infrared （FTIR） and thermogravimetric analysis （TGA）, respectively. Results show that fluoride-containing organic silane has excellent thermal stability below 185℃.
文摘The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.
基金supported by the National Natural Science Foundation of China(No.51878300)the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University(No.ZQN-YX602)+1 种基金the Science and Technology Program of Quanzhou City(No.2018C084R)the Experimental Teaching and Management Reform Project of Huaqiao University in 2023(No.SY2023J03).
文摘Perfluorinated acids(PFAs)are a new class of persistent organic pollutants that are difficult to defluorinate or remove.The reductive degradation of various representative PFAs in a biomimetic system composed of vitamin B_(12)(VB_(12))as a catalyst and nano-zero-valent iron-nickel bimetal(nFe^(0)/Ni^(0))as a reductant was investigated in this study.The effects of the self-structures of PFAs and the coexisting substances in natural water were also discussed.The results indicated that the defluorination and removal rates of PFAs were highly dependent on the length and terminal functional groups of the perfluorocarbon chain.Only Perfluorocarboxylates with C>11 and Perfluorosulfonates with C>6 were significantly degraded.Based on the analysis of the degradation products of perfluorobutanesulfonate(PFBS),perfluorohexanesulfonate(PFHxS),prefluorooctanesulfonate(PFOS),and 2-perfluoroctyl ethanol(8:2 FTOH),hydrolysis followed by the scission of C–S or C–C connecting the terminal functional groups was the dominant degradation pathway of long-chain PFAs instead of cleavage of C–C in the perfluorocarbon chain.The perfluorocarbon chain length affects the product type.It is speculated that the high bond dissociation energies of C–F bonds in short-chain PFAs hinder the occurrence of the decarboxylation-hydroxylation-elimination-hydrolysis(DHEH)pathway and make the addition of(–CF_(2)–)_(n) dominant.Meanwhile,the inhibition of SO_(4)^(2–)removal by PFOS was significant,whereas humic acid,Cl–,and dissolved oxygen had only a slight influence.Overall,this study provides new insights on the degradation of PFAs containing multiple structures and highlights the impact of the self-structure on PFAs removal.
