The effective and affordable separation of oil and water,a crucial process in the safe han dling of environmental disasters such as crude oil spills and recovery of valuable resources is a highly sought-after yet chal...The effective and affordable separation of oil and water,a crucial process in the safe han dling of environmental disasters such as crude oil spills and recovery of valuable resources is a highly sought-after yet challenging task.Herein,superhydrophobic PU sponge was fab ricated for the fast and cost-effective adsorptive separation of oil and different organic sol vents from water.Octadecyltrichlorosilane(OTS)-functionalized Fe_(3)O_(4)@SiO_(2)core-shell mi crospheres were dip-coated on the surface of porous materials via a dip-coating process thereby endowing them with superhydrophobicity.Owing to the hydrophobic interaction between OTS molecules and oil and increased capillary force in the micropores,the result ing superhydrophobic sponge served as a selective oil-sorbent scaffold for absorbing oil from oil-water mixtures,including oil-water suspensions and emulsions.Remarkably,after the recovery of the adsorbed oil via mechanical extrusion,these superhydrophobic materials could be reused multiple times and maintain their oil-water separation efficacy even afte 10 oil-water separation cycles.展开更多
It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore th...It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore the distribution, source apportionment and ecological risk assessment of PFAAs in surface water from Shijiazhuang, China. The concentrations of ΣPFAAs ranged from 19.5 to 125.9 ng/L in the investigation area. Perfluorobutanesulfonic acid(PFBS) and perfluoropentanoic acid(PFPeA) were the predominant contaminants(mean value: 14.3 ng/L and 16.6 ng/L, respectively). The distribution of PFAAs according to geospatial analysis and hierarchical clustering analysis(HCA) showed that higher levels of ΣPFAAs were detected in the southern surface water of Shijiazhuang and there was a stepwise decrease from the wet season to the dry season. Furthermore, based on source apportionment,the dominant potential sources were found to be wastewater treatment plant(WWTP) effluents and industrial discharge. The risk quotients(RQs) revealed low ecological risks of all PFAAs for aquatic organisms in Shijiazhuang surface water. Collectively, this study provided basic data for regulatory strategies for controlling PFAA pollutions in urban surface water.展开更多
Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemet...Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemethylcyclohexasiloxane[D5D(CH_(2)Cl)],were detected in water[<LOQ(Limit of quantitation)-86.3 ng/L,df(detection frequency)=23%-38%,n=112]and sediment samples[<LOQ-504 ng/g dw(dry weight),df=33%-38%,n=112]from 16 lakes located in Shengli oilfield of China,and had apparent increasing trends(31%-34%per annum)in sediments during Year 2014-2020.Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS.More specifically,compared with those of parent cVMS,volatilization(86-2558 days)and hydrolysis(135-549 days)half-lives of chlorocVMS were respectively 1.3-2.0 and 1.8-2.1 times longer.In two species of freshwater mussels(n=1050)collected from six lakes,concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea.Compared with parent cVMS,chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors(2.1-3.0)and 1.1-1.7 times longer half-lives(13-42 days).Their stronger persistence in sediment and bioaccumulation in freshwatermussels suggested that environmental emission,distribution and risks of chloro-cVMS deserve further attention.展开更多
We report on the direct generation of passively mode-locked vortex lasers in the visible spectral region, for the first time to the best of our knowledge, using a Pr :Li YF4(Pr:YLF) crystal as the gain medium. A stabl...We report on the direct generation of passively mode-locked vortex lasers in the visible spectral region, for the first time to the best of our knowledge, using a Pr :Li YF4(Pr:YLF) crystal as the gain medium. A stable mode-locked TEM00 mode has been achieved with a maximum average output power of 75 m W using a graphene saturable absorber mirror. The mode-locked pulse width is measured to be as short as about 73.4 ps at a repetition rate of about 140 MHz, and the laser wavelength is at about 721 nm with spectral width of about 0.5 nm. By slightly misaligning the laser resonator, a first-order Laguerre-Gaussian mode(LG0,1) has also been obtained with output power reduced to about 22 m W. The achieved LG0,1 mode has been verified via a home made improved Fizeau interferometer. This work provides a simple and universal method for direct generation of an ultrafast vortex laser,which can be readily extended to other spectral regions by using different laser gain mediums.展开更多
Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cy...Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cyclic methylsiloxanes(D4–D6) and twelve linear methylsiloxanes(L5–L16) in mollusks collected from seven cities along the Bohai Sea. D4–D6(df = 71%–81%) and L8–L16(df = 32%–40%) were frequently detectable in the mollusk samples, while L5–L7 were not found in any mollusk samples. Cyclic methylsiloxanes(D4–D6) were found in mollusks with the mean concentrations of 15.7 ± 12.3 ng/g ww for D4,24.6 ± 15.8 ng/g ww for D5 and 34.0 ± 23.0 ng/g ww for D6. Among the seven sampling cities, the cyclic methylsiloxanes were predominant in mollusks, with the total cyclic methylsiloxanes(sum of D4–D6, ∑ CMS) accounting for 74.2%–80.7% of the total methylsiloxanes. ∑ CMS along the coastline demonstrated a clear gradient, with the highest concentrations in mollusks at the sampling sites located in the western part of the Bohai Sea and the lowest concentrations in mollusks from cities located in the eastern part of the Bohai Sea. The biota-sediment accumulation factors for cyclic methylsiloxanes(D4–D6) and linear methylsiloxanes(L8–L16) were estimated as 0.42 ± 0.06–0.53 ± 0.06 and0.13 ± 0.03–0.19 ± 0.05, respectively.展开更多
The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the ener...The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of Cd S and C_(3)N_(4) nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature,a little higher than the melting point of thiourea.The as-prepared Cd S/C_(3)N_(4) materials exhibit high efficiency for photocatalytic hydrogen evolution reaction(HER)with the HER rate as high as 15,866μmol/(g·hr)under visible light irradiation(λ>420 nm),which is 89 and 9 times those of pristine C_(3)N_(4) and Cd S,respectively.Also,the apparent quantum efficiency(AQE)of Cd S/C_(3)N_(4)–1:2–200–2(Cd S/C_(3)N_(4)–1:2–200–2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200℃ for two hours)reaches 3.25%atλ=420±15 nm.After irradiated for more than 24 hr,the HER efficiencies of Cd S/C_(3)N_(4) do not exhibit any attenuation.The DFT calculation suggests that the charge difference causes an internal electric field from C_(3)N_(4) pointing to Cd S,which can more effectively promote the transfer of photogenerated electrons from Cd S to C_(3)N_(4).Therefore,most HER should occur on C_(3)N_(4) surface where photogenerated electrons accumulate,which largely protects Cd S from photo-corrosion.展开更多
We report on a diode-end-pumped high-power and high-energy Nd:YAG single-crystal fiber laser at 1834 nm.Two 808 nm diodes injecting about 58 W pump power into the Nd:YAG fiber have generated 3.28 W continuouswave and ...We report on a diode-end-pumped high-power and high-energy Nd:YAG single-crystal fiber laser at 1834 nm.Two 808 nm diodes injecting about 58 W pump power into the Nd:YAG fiber have generated 3.28 W continuouswave and 1.66 W Cr:ZnSe-based passively Q-switched lasers. Slope efficiencies with respect to pump powers are8.7% for the continuous-wave laser and 4.9% for the Q-switched laser. The extracted maximum pulse energy is about 266.9 μJ, and the corresponding maximum pulse peak power is 2.54 kW. These performances greatly surpass previous results regarding this specific laser emission because the laser gain medium in the form of fiber can significantly mitigate thermally induced power saturation thanks to its significantly reduced thermal lensing effect. Single-crystal fiber lasers show great potential for high average power, pulse energy, and peak power.展开更多
Rapid economic development and industrialization have left many risk sites around the world with significant or potential soil contamination due to industrial production or the shutdown or relocation of industrial fac...Rapid economic development and industrialization have left many risk sites around the world with significant or potential soil contamination due to industrial production or the shutdown or relocation of industrial facilities.Soil pollutants pose significant threats to human health,especially at sites used by the chemical,mining,and metalworking industries,among others[1].展开更多
Owing to frequent environmental monitoring of tetrabromobisphenol-A(TBBPA)analogs and their potential ecotoxicological effects on organisms,analysis of trace levels of TBBPA analogs with more non-polar and less water-...Owing to frequent environmental monitoring of tetrabromobisphenol-A(TBBPA)analogs and their potential ecotoxicological effects on organisms,analysis of trace levels of TBBPA analogs with more non-polar and less water-soluble characteristics is of great significance for studying their environmental behaviors and toxic effects.Herein,a fast and sensitive technique is developed for directly detecting aqueous TBBPA analogs,including TBBPA mono(allyl ether)(TBBPA-MAE),TBBPA mono(2,3-dibromopropyl ether)(TBBPAMDBPE),TBBPA mono(2-hydroxyethyl ether)(TBBPA-MHEE)and TBBPA mono(glycidyl ether)(TBBPAMGE),by combining solid phase microextraction(SPME)based on porous covalent organic frameworks(Porous-COFs)with constant flow desorption ionization-mass spectrometry(CFDI-MS).As chromatographic separation is replaced by constant flow desorption,each sample can be analyzed within 7 min.The hierarchical porous structures(microporous,mesoporous and macroporous)of COFs lead to the enhanced mass transfer and the easier accessibility of active sites to TBBPA analogs,so that the extraction efficiency is 2.3-3.6 times higher than pure microporous COFs,and far superior to commercial coatings.The detection limit and quantification limit of this method are 0.1-1 and 0.4-3.2 ng/L,respectively.Ultratrace levels of TBBPA analogs from 5.0 ng/L to 66 ng/L have been successfully detected in river and sea water samples,showing great potential for subsequent studies of their environmental behaviors and toxicological effects.展开更多
Molecular level characterization of dissolved organic sulfur(DOS)by electrospray ionizationFourier transform ion cyclotron resonance mass spectrometry(ESI-FTICR MS)is necessary for further understanding of the role of...Molecular level characterization of dissolved organic sulfur(DOS)by electrospray ionizationFourier transform ion cyclotron resonance mass spectrometry(ESI-FTICR MS)is necessary for further understanding of the role of DOS in the environment.Here,ESI spray solvent,a key parameter for ion production during ESI process,was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS.100%MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM,which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected.The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50%MeOH aqueous solution(731)or 50%ACN aqueous solution(653).Moreover,due to the enhancement of ionization efficiency of DOS during ESI processes,the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100%MeOH as spray solvent,which were hardly obtained using 50%MeOH aqueous solution as spray solvent.The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample.A simple method based on 100%MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied,and the results revealed more molecular information of DOS in sea DOM samples.展开更多
Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both a...Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both alloy and small size structures is of great interest in fabrication of SERS platform to in situ monitor catalytical reaction.Herein,we report a facile method to synthesize Au@AgPd trimetallic nanoflowers(Au@AgPd NFs) with both SERS and catalytic activities,through simultaneous selective growth of Ag and Pd on Au core to form highly-branched alloy shell.These nanocrystals have the properties of small sizes,defects abundance,and highly-dispersed alloy shell which offer superior catalytic activity,while the merits of monodisperse,excellent stability,and highly-branched shell and core/alloy-shell structure promise the enhanced SERS activity.We further studied their growth mechanisms,and found that the ratio of Ag to Pd,sizes of Au core,and surfactant cetyltrimethylammonium bromide together determine this special structure.Using this as-synthesized nanocrystals,a monolayer bifunctional platform with both SERS and catalytical activity was fabricated through selfassembly at air/water interface,and applied to in situ SERS monitoring the reaction process of Pdcatalyzed hydrogenation of 4-nitrothiophenol to 4-aminothio p henol.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21827815 and 42192571)。
文摘The effective and affordable separation of oil and water,a crucial process in the safe han dling of environmental disasters such as crude oil spills and recovery of valuable resources is a highly sought-after yet challenging task.Herein,superhydrophobic PU sponge was fab ricated for the fast and cost-effective adsorptive separation of oil and different organic sol vents from water.Octadecyltrichlorosilane(OTS)-functionalized Fe_(3)O_(4)@SiO_(2)core-shell mi crospheres were dip-coated on the surface of porous materials via a dip-coating process thereby endowing them with superhydrophobicity.Owing to the hydrophobic interaction between OTS molecules and oil and increased capillary force in the micropores,the result ing superhydrophobic sponge served as a selective oil-sorbent scaffold for absorbing oil from oil-water mixtures,including oil-water suspensions and emulsions.Remarkably,after the recovery of the adsorbed oil via mechanical extrusion,these superhydrophobic materials could be reused multiple times and maintain their oil-water separation efficacy even afte 10 oil-water separation cycles.
基金supported by the National Natural Science Foundation of China (Nos. 41907321, 21777182)the Natural Science Foundation of Hebei Province (No. B2019208273)State Key Laboratory of Environmental Chemistry and Ecotoxicology, RCEES, Chinese Academy of Sciences (No. KF2018-17)。
文摘It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore the distribution, source apportionment and ecological risk assessment of PFAAs in surface water from Shijiazhuang, China. The concentrations of ΣPFAAs ranged from 19.5 to 125.9 ng/L in the investigation area. Perfluorobutanesulfonic acid(PFBS) and perfluoropentanoic acid(PFPeA) were the predominant contaminants(mean value: 14.3 ng/L and 16.6 ng/L, respectively). The distribution of PFAAs according to geospatial analysis and hierarchical clustering analysis(HCA) showed that higher levels of ΣPFAAs were detected in the southern surface water of Shijiazhuang and there was a stepwise decrease from the wet season to the dry season. Furthermore, based on source apportionment,the dominant potential sources were found to be wastewater treatment plant(WWTP) effluents and industrial discharge. The risk quotients(RQs) revealed low ecological risks of all PFAAs for aquatic organisms in Shijiazhuang surface water. Collectively, this study provided basic data for regulatory strategies for controlling PFAA pollutions in urban surface water.
基金supported by the National Key Research and Development Program of China (No.2019YFC1804501)the National Natural Science Foundation of China (Nos.22036007,21876189, 21607112)+1 种基金the Youth Innovation Promotion Association CAS, China Postdoctoral Science Foundation (No.2021M693320)the Tianjin Fundamental Research Program of the Tianjin Committee of Science and Technology (No.19JCQNJC08200)。
文摘Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemethylcyclohexasiloxane[D5D(CH_(2)Cl)],were detected in water[<LOQ(Limit of quantitation)-86.3 ng/L,df(detection frequency)=23%-38%,n=112]and sediment samples[<LOQ-504 ng/g dw(dry weight),df=33%-38%,n=112]from 16 lakes located in Shengli oilfield of China,and had apparent increasing trends(31%-34%per annum)in sediments during Year 2014-2020.Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS.More specifically,compared with those of parent cVMS,volatilization(86-2558 days)and hydrolysis(135-549 days)half-lives of chlorocVMS were respectively 1.3-2.0 and 1.8-2.1 times longer.In two species of freshwater mussels(n=1050)collected from six lakes,concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea.Compared with parent cVMS,chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors(2.1-3.0)and 1.1-1.7 times longer half-lives(13-42 days).Their stronger persistence in sediment and bioaccumulation in freshwatermussels suggested that environmental emission,distribution and risks of chloro-cVMS deserve further attention.
基金Natural Science Foundation of Fujian Province of China(2018J01108)National Natural Science Foundation of China(91750115)International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology,Shenzhen University(2DMOST2018026)
文摘We report on the direct generation of passively mode-locked vortex lasers in the visible spectral region, for the first time to the best of our knowledge, using a Pr :Li YF4(Pr:YLF) crystal as the gain medium. A stable mode-locked TEM00 mode has been achieved with a maximum average output power of 75 m W using a graphene saturable absorber mirror. The mode-locked pulse width is measured to be as short as about 73.4 ps at a repetition rate of about 140 MHz, and the laser wavelength is at about 721 nm with spectral width of about 0.5 nm. By slightly misaligning the laser resonator, a first-order Laguerre-Gaussian mode(LG0,1) has also been obtained with output power reduced to about 22 m W. The achieved LG0,1 mode has been verified via a home made improved Fizeau interferometer. This work provides a simple and universal method for direct generation of an ultrafast vortex laser,which can be readily extended to other spectral regions by using different laser gain mediums.
基金supported by the National Natural Science Foundation of China (Nos.21537004,21777182,21621064,21407159)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB14010201)
文摘Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cyclic methylsiloxanes(D4–D6) and twelve linear methylsiloxanes(L5–L16) in mollusks collected from seven cities along the Bohai Sea. D4–D6(df = 71%–81%) and L8–L16(df = 32%–40%) were frequently detectable in the mollusk samples, while L5–L7 were not found in any mollusk samples. Cyclic methylsiloxanes(D4–D6) were found in mollusks with the mean concentrations of 15.7 ± 12.3 ng/g ww for D4,24.6 ± 15.8 ng/g ww for D5 and 34.0 ± 23.0 ng/g ww for D6. Among the seven sampling cities, the cyclic methylsiloxanes were predominant in mollusks, with the total cyclic methylsiloxanes(sum of D4–D6, ∑ CMS) accounting for 74.2%–80.7% of the total methylsiloxanes. ∑ CMS along the coastline demonstrated a clear gradient, with the highest concentrations in mollusks at the sampling sites located in the western part of the Bohai Sea and the lowest concentrations in mollusks from cities located in the eastern part of the Bohai Sea. The biota-sediment accumulation factors for cyclic methylsiloxanes(D4–D6) and linear methylsiloxanes(L8–L16) were estimated as 0.42 ± 0.06–0.53 ± 0.06 and0.13 ± 0.03–0.19 ± 0.05, respectively.
基金supported by National Key Research and Development Program of China(No.2016YFA0203100)the National Natural Science Foundation of China(Nos.21537004,21777169,and 21621064)the Beijing Municipal Natural Science Foundation(No.8202046)。
文摘The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of Cd S and C_(3)N_(4) nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature,a little higher than the melting point of thiourea.The as-prepared Cd S/C_(3)N_(4) materials exhibit high efficiency for photocatalytic hydrogen evolution reaction(HER)with the HER rate as high as 15,866μmol/(g·hr)under visible light irradiation(λ>420 nm),which is 89 and 9 times those of pristine C_(3)N_(4) and Cd S,respectively.Also,the apparent quantum efficiency(AQE)of Cd S/C_(3)N_(4)–1:2–200–2(Cd S/C_(3)N_(4)–1:2–200–2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200℃ for two hours)reaches 3.25%atλ=420±15 nm.After irradiated for more than 24 hr,the HER efficiencies of Cd S/C_(3)N_(4) do not exhibit any attenuation.The DFT calculation suggests that the charge difference causes an internal electric field from C_(3)N_(4) pointing to Cd S,which can more effectively promote the transfer of photogenerated electrons from Cd S to C_(3)N_(4).Therefore,most HER should occur on C_(3)N_(4) surface where photogenerated electrons accumulate,which largely protects Cd S from photo-corrosion.
基金National Natural Science Foundation of China(NSFC)(61575164)Natural Science Foundation of Fujian Province of China(2018J01108)+2 种基金Principal Fund of Xiamen University(20720180082)Bulgarian National Science Fund(DNTS 01/9/2016)Science and Technology Plan Projects of Xuzhou,China(KC16HG232)
文摘We report on a diode-end-pumped high-power and high-energy Nd:YAG single-crystal fiber laser at 1834 nm.Two 808 nm diodes injecting about 58 W pump power into the Nd:YAG fiber have generated 3.28 W continuouswave and 1.66 W Cr:ZnSe-based passively Q-switched lasers. Slope efficiencies with respect to pump powers are8.7% for the continuous-wave laser and 4.9% for the Q-switched laser. The extracted maximum pulse energy is about 266.9 μJ, and the corresponding maximum pulse peak power is 2.54 kW. These performances greatly surpass previous results regarding this specific laser emission because the laser gain medium in the form of fiber can significantly mitigate thermally induced power saturation thanks to its significantly reduced thermal lensing effect. Single-crystal fiber lasers show great potential for high average power, pulse energy, and peak power.
基金This work was supported by the National Key Research and Development Project of China(2019YFC1804500).
文摘Rapid economic development and industrialization have left many risk sites around the world with significant or potential soil contamination due to industrial production or the shutdown or relocation of industrial facilities.Soil pollutants pose significant threats to human health,especially at sites used by the chemical,mining,and metalworking industries,among others[1].
基金financially supported by the National Natural Science Foundation of China(Nos.21922402,21976185)the Innovation Academy for Green Manufacture,Chinese Academy of Sciences(No.IAGM2020C20)。
文摘Owing to frequent environmental monitoring of tetrabromobisphenol-A(TBBPA)analogs and their potential ecotoxicological effects on organisms,analysis of trace levels of TBBPA analogs with more non-polar and less water-soluble characteristics is of great significance for studying their environmental behaviors and toxic effects.Herein,a fast and sensitive technique is developed for directly detecting aqueous TBBPA analogs,including TBBPA mono(allyl ether)(TBBPA-MAE),TBBPA mono(2,3-dibromopropyl ether)(TBBPAMDBPE),TBBPA mono(2-hydroxyethyl ether)(TBBPA-MHEE)and TBBPA mono(glycidyl ether)(TBBPAMGE),by combining solid phase microextraction(SPME)based on porous covalent organic frameworks(Porous-COFs)with constant flow desorption ionization-mass spectrometry(CFDI-MS).As chromatographic separation is replaced by constant flow desorption,each sample can be analyzed within 7 min.The hierarchical porous structures(microporous,mesoporous and macroporous)of COFs lead to the enhanced mass transfer and the easier accessibility of active sites to TBBPA analogs,so that the extraction efficiency is 2.3-3.6 times higher than pure microporous COFs,and far superior to commercial coatings.The detection limit and quantification limit of this method are 0.1-1 and 0.4-3.2 ng/L,respectively.Ultratrace levels of TBBPA analogs from 5.0 ng/L to 66 ng/L have been successfully detected in river and sea water samples,showing great potential for subsequent studies of their environmental behaviors and toxicological effects.
基金supported by the National Basic Research Pro-gram of China(973)(No.2014CB441102)the National Nat-ural Science Foundation of China(Nos.21537004,21477140,21007079)the grants from the Instrument Function De-velopment Program of the Chinese Academy of Sciences。
文摘Molecular level characterization of dissolved organic sulfur(DOS)by electrospray ionizationFourier transform ion cyclotron resonance mass spectrometry(ESI-FTICR MS)is necessary for further understanding of the role of DOS in the environment.Here,ESI spray solvent,a key parameter for ion production during ESI process,was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS.100%MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM,which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected.The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50%MeOH aqueous solution(731)or 50%ACN aqueous solution(653).Moreover,due to the enhancement of ionization efficiency of DOS during ESI processes,the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100%MeOH as spray solvent,which were hardly obtained using 50%MeOH aqueous solution as spray solvent.The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample.A simple method based on 100%MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied,and the results revealed more molecular information of DOS in sea DOM samples.
基金supported by the National Key R&D Program of China(No.2016YFA0203102)the National Natural Science Foundation of China(Nos.21620102008 and 21827815)。
文摘Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both alloy and small size structures is of great interest in fabrication of SERS platform to in situ monitor catalytical reaction.Herein,we report a facile method to synthesize Au@AgPd trimetallic nanoflowers(Au@AgPd NFs) with both SERS and catalytic activities,through simultaneous selective growth of Ag and Pd on Au core to form highly-branched alloy shell.These nanocrystals have the properties of small sizes,defects abundance,and highly-dispersed alloy shell which offer superior catalytic activity,while the merits of monodisperse,excellent stability,and highly-branched shell and core/alloy-shell structure promise the enhanced SERS activity.We further studied their growth mechanisms,and found that the ratio of Ag to Pd,sizes of Au core,and surfactant cetyltrimethylammonium bromide together determine this special structure.Using this as-synthesized nanocrystals,a monolayer bifunctional platform with both SERS and catalytical activity was fabricated through selfassembly at air/water interface,and applied to in situ SERS monitoring the reaction process of Pdcatalyzed hydrogenation of 4-nitrothiophenol to 4-aminothio p henol.
