Fluorine(F)-enriched soils,resulting from geogenic processes or superimposed by anthropogenic activities,have raised significant concerns due to their phytotoxicity and potential threats to human health.Soils in centr...Fluorine(F)-enriched soils,resulting from geogenic processes or superimposed by anthropogenic activities,have raised significant concerns due to their phytotoxicity and potential threats to human health.Soils in central Guizhou Province exhibit F enrichment,with a mean F concentration of 1067 mg/kg.However,the associated human health risks and geochemical mechanisms driving F enrichment in these soils remain insufficiently understood.In areas with a natural geological background,the average concentrations of F in rice,vegetables,drinking water,and ambient air are 1.54 mg/kg,0.54 mg/kg,0.16 mg/L,and 0.29μg/m^(3),respectively.In contrast,samples collected near phosphorous chemical plants demonstrate elevated F concentrations:1.78 mg/kg in rice,1.53 mg/kg in vegetables,0.20 mg/L in drinking water,and 11.98μg/m^(3) in ambient air.Fluorine in soils was immobilized by apatite and clay minerals,and hardly transferred into water and crops.The fixation of F-by Ca^(2+)in water and by Fe/Al hydroxides and clay minerals in bottom sediment further reduces F concentrations in water.As a result,hazard quotient(HQ)values below 1.0 indicate negligible fluorine-related health risk in geological background regions.However,ambient air near phosphorous chemical plant exhibited a 41.3-fold increase in F concentration compared to geological background regions.Fluorine-laden emissions can be directly inhaled or deposited on vegetable leaves and orally ingested into human bodies.Improvement of F-rich waste gas disposal and restricted leafy vegetable cultivation are effective measures to reduce F health risks in phosphorous chemical plant regions.展开更多
Practical application of Na3SbS4(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of dual-s...Practical application of Na3SbS4(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of dual-site doped Na_(3-2x)Sb_(1-x)W_(x)S_(4-x)F_(x)(x=0,0.12,0.24,0.36)electrolytes through high-energy ball milling followed by high-temperature sintering is prepared,where tungsten(W)substitutes for antimony(Sb)and fluorine(F)replaces sulfur(S)in the NSS lattice.The co-doping of W and F not only broadens the interplanar spacing of NSS but also promotes the stable formation of the cubic phase of NSS,thereby effectively enhancing the transport ability of sodium ions within NSS.Among them,Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24) exhibits the highest ionic conductivity of 4.45 mS·cm^(-1).Furthermore,F doping facilitates the in-situ formation of NaF between the electrolyte and metallic sodium,significantly improving interfacial stability.Electrochemical evaluation shows that the Na/Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na symmetric cell achieves a high critical current density of 1.65 mA·cm^(-2) and maintains stable sodium plating/stripping cycling for 500 h at 0.1 mA·cm^(-2).Additionally,the TiS2/Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na full cell exhibits outstanding cycling stability and rate capability.展开更多
Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Comp...Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Compared with oxide FEs,polymer FEs possess good flexible and shape adaptability,making them promising candidates for flexible electronics and biocompatible devices[4].展开更多
Several conjugate components represent the aquatic ecosystem of Lake Baikal:Baikal water(surface and deep water),groundwater from boreholes,water of numerous Baikal tributaries,cold and hot mineral springs around Lake...Several conjugate components represent the aquatic ecosystem of Lake Baikal:Baikal water(surface and deep water),groundwater from boreholes,water of numerous Baikal tributaries,cold and hot mineral springs around Lake Baikal,and the Angara River,the only runoff reflecting all this aquatic diversity.River waters in the Baikal region are known to be deficient in some vital elements,including fluorine.This article discusses the features of the fluorine distribution in the water from the conjugate components of the Baikal ecosystem.Fluorine ion concentrations in the water of the Baikal ecosystem was determined using the potentiometric method.The study represents the monitoring that was carried out between 1997 and 2022 years.We determine likely causes of high and low fluorine concentrations in the water from different components,propose and substantiate the fluorine sources,geological and geochemical model of its influx and distribution features in the water of the Baikal ecosystem.展开更多
Zirconium-based metal-organic cages(Zr-MOCs)typically exhibit high stability,but their structural and application reports are scarce due to stringent crystallization conditions.We have successfully fluorinated the cla...Zirconium-based metal-organic cages(Zr-MOCs)typically exhibit high stability,but their structural and application reports are scarce due to stringent crystallization conditions.We have successfully fluorinated the classical Zr-MOCs(ZrT-3)for the first time,obtaining the fluorinated MOCs(ZrT-3-F).Notably,ZrT-3-F not only inherits the high stability of its parent structure,but also acts as a catalyst for the effective oxidation of benzyl thioether for the first time.The reaction can reach a conversion rate of 99%in 6 h,and the selectivity reaches 95%,which far exceeds the non-fluorinated ZrT-3.This work proves that the specific functionalization of the classical Zr-MOCs can further expand their application potential,such as catalysis.展开更多
Fluorine(F)substitution in polymers modulates both molecular energy levels and film morphology;however,its impact on exciton–vibrational coupling and molecular reorganization energy is often neglected.Herein,we syste...Fluorine(F)substitution in polymers modulates both molecular energy levels and film morphology;however,its impact on exciton–vibrational coupling and molecular reorganization energy is often neglected.Herein,we systematically investigated F-modified polymers(PBTA-PSF,PBDB-PSF)and their nonfluorinated counterparts(PBTA-PS,PBDB-PS)through simulations and experiments.We found that F atoms effectively lower the vibrational frequency of the molecular skeleton and suppress exciton–vibration coupling,thereby reducing the nonradiative decay rate.Moreover,introducing F atoms significantly decreases the reorganization energy for the S_(0)→S_(1) and S_(0)→cation transitions while increasing the reorganization energy for the S_(1)→S_(0) and cation→S_(0) transitions.These changes facilitate exciton dissociation and reduce the energy loss caused by dissociation and nonradiative recombination of excitons.Additionally,introducing F atoms into polymers enhances theπ–πstacking strength and the crystal coherence length in both neat and blended films,ultimately resulting in improvements in the power conversion efficiency of PBTA-PSF:L8-BO and PBDB-PSF:L8-BO are 16.51%and 17.59%,respectively.This study provides valuable insights for designing organic semiconductor materials to minimize energy loss and achieve a higher power conversion efficiency.展开更多
Proton ceramic fuel cell efficiently converts chemical energy into electrical energy,representing a pivotal component of future energy systems.However,its current performance is hindered by limitations in cathode and ...Proton ceramic fuel cell efficiently converts chemical energy into electrical energy,representing a pivotal component of future energy systems.However,its current performance is hindered by limitations in cathode and electrolyte materials,thereby impeding commercialization.Anion doping emerges as a promising strategy to enhance the electrochemical efficiency of perovskite-based cathodes and electrolytes.However,integrating this approach within a single-cell structure still requires further research.In this study,F-doped perovskite oxides BaCo_(0.4)Fe_(0.4)Zr_(0.1)Y_(0.1)O_(2.9-δ)F_(0.1)(BCFZYF)and BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(2.9-δ)F_(0.1)(BZCYYbF)were synthesized for use as the cathode and electrolyte,respectively,in proton ceramic fuel cells.Our findings demonstrate that F-doped perovskite oxides exhibit superior electrochemical performance and enhanced structural stability.Furthermore,doping both electrodes and electrolytes with F ions improves their interfacial compatibility.The cell configuration BCFZYF|BZCYYbF|Ni-BZCYYbF achieved a peak power density of 998 mW·cm^(−2)at 650℃using H_(2)as fuel,and it maintained stable operation for over 400 h at 550℃with a current density of 400 mA·cm^(−2).This research underscores an effective strategy for enhancing the performance and durability of proton ceramic fuel cells.展开更多
Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decompositio...Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decomposition was developed.The thermodynamic analysis of sub-molten salt reaction indicates that the recovery of rare earths from the slag using sub-molten salt medium is thermodynamically feasible.In this process,the rare earth fluoride and lithium in the slag are almost transformed into rare earth hydroxide,sodium fluoride and lithium hydroxide,fluorine and lithium are transferred into the washing solution,and the rare earths in the residues can be leached into solution by acid leaching.Under the optimum reaction conditions of reaction temperature 200℃,reaction time 3 h,NaOH initial concentration 80%,NaOH-Slag mass ratio 3:1,the leaching efficiency of rare earths,fluorine and lithium can reach to 99.05%,98.23% and 99.22%.After evaporation,the fluorine and lithium in the washing solution can be obtained in the forms of sodium fluoride and lithium fluoride,the recovery efficiency reach 95.5%and 92.8%,respectively.The RE oxides(99.53%) can be obtained from the leaching solution after precipitation and roasting.展开更多
Rare earth fluoride molten-salt electrolytic slag(REFES)is a precious rare earth element(REE)secondary resource,and conside rable amounts of REEs exist in REFES as REF_(3);they are difficult to dissolve in acid or wat...Rare earth fluoride molten-salt electrolytic slag(REFES)is a precious rare earth element(REE)secondary resource,and conside rable amounts of REEs exist in REFES as REF_(3);they are difficult to dissolve in acid or water and impede efficient REE extraction.In REFES recovery,the REF_(3)species in REFES are usually transformed into acid-soluble rare earth compounds by NaOH roasting or sulfating roasting and then extracted by acid leaching,Moreover,the fluorides in REFES are released as HF gas in the roasting process or enter the liquid phase during the water washing process;both of these processes cause fluorine pollution.Fixing the fluorine into the solid slag provides a way to avoid fluorine pollution.In this study,a novel method was proposed to extract REEs from REFES via MgCl_(2)roasting followed by HCl leaching.Thermodynamics calculations and the rmogravimetry-differential thermal analyses(TG-DTA)were conducted to investigate the reactions occurring in the roasting process,First,MgCl_(2)reacts with the REF_3and RE_(2)O_(3)to form RECl_(3)and REOCl,respectively.Second,the RECI_(3)absorbs water and forms RE(OH)_(3).Third,MgCl_(2)·6H_(2)O is gradually dehydrated to MgCl_(2)·2H_(2)O and reacts with REF_(3)and RE(OH)_(3),and REOCl,MgF_(2)and MgO are formed.Through HCl leaching,the REOCl in the roasting products is leached by HCl acid,while fluoride re mains in the solid slag as MgF_2.The optimum experimental conditions are as follows:mass ratio of MgCl_(2)to REFES of 30%,roasting temperature of 700℃,roasting time of 2 h,hydrochloride acid concentration of 4 mol/L,leaching time of 2 h,leaching temperature of 90℃and leaching L/S ratio of 20:1.The efficiencies for total leaching of the REEs,La,Ce,Pr,and Nd are 99.13%,99.20%,98.42%,99.38%,and 99.08%,respectively.Moreover,the concentration of fluoride in the leaching solution is 2.191×10^(-6)mol/L.This method has a short process flow with low reagent costs,and the problem of fluoride pollution from REFES recovery is solved;thus,our study has great industrial application potential.展开更多
Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2D)nets is a promising but underdeveloped strategy.Herein,we report the design and synthesis of a fluorine...Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2D)nets is a promising but underdeveloped strategy.Herein,we report the design and synthesis of a fluorine functionalized 3DCOF(3D-An-COF-F)formed by entangled 2D sql nets.The structure of 3D-An-COF-F was determined by the combination of continuous rotation electron diffraction technique and modelling based on the chemical information from real space.Interestingly,compared to the isostructural 3D-An-COF without F atom s,3DAn-COF-F showed an improved CO_(2)sorption ability and higher CO_(2)/N_(2)selectivity.Our study not only demonstrated the generality of constructing 3D COFs with entangled 2D nets by introducing bulky groups vertically in planar building blocks,but also will expand the diversity of 3D COFs for various applications.展开更多
Because of the unique reactivity of sulfonyl fluoride(SO_(2)F)group,such compound has found increasing applications in the areas of organic synthesis,new drug development,pesticide,material science and click chemistry...Because of the unique reactivity of sulfonyl fluoride(SO_(2)F)group,such compound has found increasing applications in the areas of organic synthesis,new drug development,pesticide,material science and click chemistry,etc.It is of current interest to develop novel strategies and methods for the facile preparation of sulfonyl fluorides in a green and highly efficient manner[1,2].Although the traditional approach for the synthesis of sulfonyl fluorides relies on the nucleophilic substitution of fluoride atom with sulfonyl chlorides.展开更多
In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling ...In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling pathway. This work reveals a highly complex conformational energy landscape of β-arrestin-1, and illuminates the molecular mechanism of the membrane phosphoinositide PIP2-induced β-arrestin-1 activation at residue level.(https://doi.org/10.1038/s41467-023-43694-1).展开更多
NH_(2)-MIL-125 is one of the most promising metal-organic frameworks(MOFs)for use as an adsorbent to remove nitrogen-containing compounds(NCCs)from fuels.In this study,NH_(2)-MIL-125 was further modified by loading th...NH_(2)-MIL-125 is one of the most promising metal-organic frameworks(MOFs)for use as an adsorbent to remove nitrogen-containing compounds(NCCs)from fuels.In this study,NH_(2)-MIL-125 was further modified by loading the highly electronegative F and the heteropoly acid phosphomolybdic acid hydrate(PMA).Hydrogen bonds are suggested to form between F and PMA.X-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that the addition of these elements altered the morphology of NH_(2)-MIL-125,resulting in the growth of sectional octahedrons and cubes.The adsorptive denitrogenation(ADN)activity of 10%PMA@M125 was 1.7 times greater than that of NH_(2)-MIL-125 without F and PMA.The synergistic effect of F and PMA on the morphology and structure of NH_(2)-MIL-125 was examined,with a focus on different PMA contents.This study provides a simple method for modifying the morphology and structure of NH_(2)-MIL-125 by adding the required elements.展开更多
In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization(ISO) name during the last decade are described.The predo...In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization(ISO) name during the last decade are described.The predominant approach for fluorine introduction of these agrochemicals is to use a fluorine-containing building block. Here we present how the fluorine-containing building blocks are introduced into these agrochemicals. The synthetic methods of fluorine-containing building blocks that are not easily available are also specifically discussed. Fluoroarenes, difluomethylarenes and trifluomethylarenes are the main building blocks that have been used in this review. Fluorine-containing small molecules, such as alcohol,amine, ketoester, olefin are also widely used. The only example of late-stage fluorination is the synthesis of fungicide quinofumelin. We believe the fluorine introduction methods described here can provide ideas for the development of new and economical pesticide synthetic routes, and stimulate researchers to develop new fluorine incorporation methods and create new pesticides.展开更多
Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides...Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides to optimize solid electrolyte interfaces and provide dynamic protection of electrodes to regulate the reaction and function performance of batteries.Nonetheless,the shuttle effect and the sluggish redox reaction kinetics emphasize the potential bottlenecks of lithium-sulfur batteries.Whether fluorine modulation regulate the reaction process of Li-S chemistry?Here,the TiOF/Ti_(3)C_(2)MXene nanoribbons with a tailored F distribution were constructed via an NH4F fluorinated method.Relying on in situ characterizations and electrochemical analysis,the F activates the catalysis function of Ti metal atoms in the consecutive redox reaction.The positive charge of Ti metal sites is increased due to the formation of O-Ti-F bonds based on the Lewis acid-base mechanism,which contributes to the adsorption of polysulfides,provides more nucleation sites and promotes the cleavage of S-S bonds.This facilitates the deposition of Li_(2)S at lower overpotentials.Additionally,fluorine has the capacity to capture electrons originating from Li_(2)S dissolution due to charge compensation mechanisms.The fluorine modulation strategy holds the promise of guiding the construction of fluorine-based catalysts and facilitating the seamless integration of multiple consecutive heterogeneous catalytic processes.展开更多
Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of...Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of cation disorder can effectively suppress the detrimental two-phase reaction to realize high capacities in a wide voltage range.However,the continuous capacity decay during cycles has hindered the widespread application of these cathode materials.Inorganic fluorides exhibit excellent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially disordered spinel cathode(Li_(1.6)Mn_(1.6)O_(3.7)F_(0.3,)LMOF1.6)was initially applied to investigate the impacts of fluorination on the surface structure and electrochemical performances.The inorganic fluorinated layer,mainly containing LiF,was distributed uniformly on the surface of LMOF1.6nanoparticles after fluorination for an appropriate time without the turbulence caused by the valency of manganese cation,which improved the capacity retention and rate capability by the suppression of structural damage,parasitic reaction,and cation dissolution.The LMOF1.6cathode fluorinated for 0.5 h exhibited a capacity of283.6 mAh·g^(-1)at 50 mA·g^(-1)and an enhanced capacity retention of 29.6%after 50 cycles in the voltage range of1.5-4.8 V,as compared to the pristine LMOF1.6 with only27.9%capacity retention.展开更多
Bisphenol A dicyanate ester resins modified by fluorine-containing liquid crystal compound(LCFE)are applied as polymer matrix(LCFE-BADCy),poly(p-phenylene-2,6-benzobisoxazole)(PBO)fibers as rein-forcements,and fluorin...Bisphenol A dicyanate ester resins modified by fluorine-containing liquid crystal compound(LCFE)are applied as polymer matrix(LCFE-BADCy),poly(p-phenylene-2,6-benzobisoxazole)(PBO)fibers as rein-forcements,and fluorine/adamantane PBO precursor(pre FABPBO)as interfacial compatibilizer to prepare the corresponding PBO fibers/FABPBO/LCFE-BADCy wave-transparent laminated composites.LCFE could improve the order degree of BADCy cured network,in favor of enhancing the wave-transparent perfor-mance,mechanical properties,and intrinsic thermal conductivity.The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature(25–200℃)and frequency(10^(4)–10^(7) Hz and 8.2–12.4 GHz)stable with the value of 2.49 and 0.003 under 10^(6) Hz at 25℃,and the corresponding wave transmission efficiency is 95.0%,higher than that of 92.5%for PBO fibers/BADCy com-posites.The interlamellar shear strength and flexural strength are respectively 50.7 MPa and 682.5 MPa,38.1%and 16.2%higher than those of PBO fibers/BADCy composites.Besides,the volume resistivity,breakdown voltage,heat resistance index,glass transition temperature,flame retardant grade,and ul-timate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×10^(15)Ωcm,29.75 kV/mm,217.2℃,245.7℃,V-1 grade,and 33.6%,expected to be performed as a new generation of“lightweight/loading/wave-transparent”electromagnetic window materials in advanced military weapons and civil communication base station.展开更多
The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion ...The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.展开更多
Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test res...Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test results of 36 groundwater samples show that fluorine concentration in shallow groundwater is 0.18–6.7 mg/L and 50 % of the samples exceed the Chinese drinking water quality standard. There exists a significant negative correlation in content between Ca2+ and F - . The correlations between fluorine concentration and other cations (for example Na+, K+, Mg2+) are not significant. The content of dissolved fluorine from the flooding sediments of the Huanghe River that varying from 5.6 mg/kg to 15.2 mg/kg plays an important role in forming the high fluorine groundwater. Usually, the dissolved fluorine content in silt is much higher than that in silty clay and clay. According to the geological investigation fluorine content in deep groundwater (over 60 m) is less than 1.0 mg/L and suitable for drinking, so it is an effective measure to prevent endemic fluorosis by extracting deep groundwater in disease areas.展开更多
A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrenc...A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrence and accumulation of the F in coals and its potential hazard to human and environment. Analytical data of coal samples were referred to study the great difference of the F content between coals and gangue. The results show that the average value of the F in the coal samples collected in different coalfields of China is 304x10^6, while that of gangue samples is surprisingly 1 319x10^6, especially the F content of coal ash from Bangmai in Yunnan Province reaches 4 800x10^6. It has been proved in many provinces of China that burning the coal and clay mixture can produce F contamination.展开更多
基金supported by the projects of the China Geological Survey(DD20230543,DD20221770).
文摘Fluorine(F)-enriched soils,resulting from geogenic processes or superimposed by anthropogenic activities,have raised significant concerns due to their phytotoxicity and potential threats to human health.Soils in central Guizhou Province exhibit F enrichment,with a mean F concentration of 1067 mg/kg.However,the associated human health risks and geochemical mechanisms driving F enrichment in these soils remain insufficiently understood.In areas with a natural geological background,the average concentrations of F in rice,vegetables,drinking water,and ambient air are 1.54 mg/kg,0.54 mg/kg,0.16 mg/L,and 0.29μg/m^(3),respectively.In contrast,samples collected near phosphorous chemical plants demonstrate elevated F concentrations:1.78 mg/kg in rice,1.53 mg/kg in vegetables,0.20 mg/L in drinking water,and 11.98μg/m^(3) in ambient air.Fluorine in soils was immobilized by apatite and clay minerals,and hardly transferred into water and crops.The fixation of F-by Ca^(2+)in water and by Fe/Al hydroxides and clay minerals in bottom sediment further reduces F concentrations in water.As a result,hazard quotient(HQ)values below 1.0 indicate negligible fluorine-related health risk in geological background regions.However,ambient air near phosphorous chemical plant exhibited a 41.3-fold increase in F concentration compared to geological background regions.Fluorine-laden emissions can be directly inhaled or deposited on vegetable leaves and orally ingested into human bodies.Improvement of F-rich waste gas disposal and restricted leafy vegetable cultivation are effective measures to reduce F health risks in phosphorous chemical plant regions.
文摘Practical application of Na3SbS4(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of dual-site doped Na_(3-2x)Sb_(1-x)W_(x)S_(4-x)F_(x)(x=0,0.12,0.24,0.36)electrolytes through high-energy ball milling followed by high-temperature sintering is prepared,where tungsten(W)substitutes for antimony(Sb)and fluorine(F)replaces sulfur(S)in the NSS lattice.The co-doping of W and F not only broadens the interplanar spacing of NSS but also promotes the stable formation of the cubic phase of NSS,thereby effectively enhancing the transport ability of sodium ions within NSS.Among them,Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24) exhibits the highest ionic conductivity of 4.45 mS·cm^(-1).Furthermore,F doping facilitates the in-situ formation of NaF between the electrolyte and metallic sodium,significantly improving interfacial stability.Electrochemical evaluation shows that the Na/Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na symmetric cell achieves a high critical current density of 1.65 mA·cm^(-2) and maintains stable sodium plating/stripping cycling for 500 h at 0.1 mA·cm^(-2).Additionally,the TiS2/Na_(2.52)Sb|_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na full cell exhibits outstanding cycling stability and rate capability.
基金support from the Natural Science Fund for Colleges and Universities in Jiangsu Province(24KJB430029)the Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(NY224032,NY225006).
文摘Ferroelectrics(FEs)have shown great potential in sensors,actuators,and electrocaloric cooling due to their direct cross-couplings between electric polarization and mechanical,thermal,and dielectric properties[1−3]Compared with oxide FEs,polymer FEs possess good flexible and shape adaptability,making them promising candidates for flexible electronics and biocompatible devices[4].
基金the framework of the IGC SB RAS project(No.0284-2021-0003)supported by the RFFR ofi_m project(No.17-29-05022).
文摘Several conjugate components represent the aquatic ecosystem of Lake Baikal:Baikal water(surface and deep water),groundwater from boreholes,water of numerous Baikal tributaries,cold and hot mineral springs around Lake Baikal,and the Angara River,the only runoff reflecting all this aquatic diversity.River waters in the Baikal region are known to be deficient in some vital elements,including fluorine.This article discusses the features of the fluorine distribution in the water from the conjugate components of the Baikal ecosystem.Fluorine ion concentrations in the water of the Baikal ecosystem was determined using the potentiometric method.The study represents the monitoring that was carried out between 1997 and 2022 years.We determine likely causes of high and low fluorine concentrations in the water from different components,propose and substantiate the fluorine sources,geological and geochemical model of its influx and distribution features in the water of the Baikal ecosystem.
基金supported by National Natural Science Foundation of China(Nos.22201046,22371054)Local Innovation Research Team Project of Guangdong Pearl River Talent Plan(No.2017BT01Z032)。
文摘Zirconium-based metal-organic cages(Zr-MOCs)typically exhibit high stability,but their structural and application reports are scarce due to stringent crystallization conditions.We have successfully fluorinated the classical Zr-MOCs(ZrT-3)for the first time,obtaining the fluorinated MOCs(ZrT-3-F).Notably,ZrT-3-F not only inherits the high stability of its parent structure,but also acts as a catalyst for the effective oxidation of benzyl thioether for the first time.The reaction can reach a conversion rate of 99%in 6 h,and the selectivity reaches 95%,which far exceeds the non-fluorinated ZrT-3.This work proves that the specific functionalization of the classical Zr-MOCs can further expand their application potential,such as catalysis.
基金supported by the National Natural Science Foundation of China(Grant No.62027822)the National R&D Program of China(Grant No.2019YFA0706402).
文摘Fluorine(F)substitution in polymers modulates both molecular energy levels and film morphology;however,its impact on exciton–vibrational coupling and molecular reorganization energy is often neglected.Herein,we systematically investigated F-modified polymers(PBTA-PSF,PBDB-PSF)and their nonfluorinated counterparts(PBTA-PS,PBDB-PS)through simulations and experiments.We found that F atoms effectively lower the vibrational frequency of the molecular skeleton and suppress exciton–vibration coupling,thereby reducing the nonradiative decay rate.Moreover,introducing F atoms significantly decreases the reorganization energy for the S_(0)→S_(1) and S_(0)→cation transitions while increasing the reorganization energy for the S_(1)→S_(0) and cation→S_(0) transitions.These changes facilitate exciton dissociation and reduce the energy loss caused by dissociation and nonradiative recombination of excitons.Additionally,introducing F atoms into polymers enhances theπ–πstacking strength and the crystal coherence length in both neat and blended films,ultimately resulting in improvements in the power conversion efficiency of PBTA-PSF:L8-BO and PBDB-PSF:L8-BO are 16.51%and 17.59%,respectively.This study provides valuable insights for designing organic semiconductor materials to minimize energy loss and achieve a higher power conversion efficiency.
基金supported by the National Natural Science Foundation of China(No.22278203)The authors appreciate the support of Zhejiang Zheneng Technology and Environment Group Co.,Ltd’s project(No.TD-KJ-23-005:Methanation of carbon monoxide coupled with in-situ formed hydrogen in a low-temperature SOEC reactor).
文摘Proton ceramic fuel cell efficiently converts chemical energy into electrical energy,representing a pivotal component of future energy systems.However,its current performance is hindered by limitations in cathode and electrolyte materials,thereby impeding commercialization.Anion doping emerges as a promising strategy to enhance the electrochemical efficiency of perovskite-based cathodes and electrolytes.However,integrating this approach within a single-cell structure still requires further research.In this study,F-doped perovskite oxides BaCo_(0.4)Fe_(0.4)Zr_(0.1)Y_(0.1)O_(2.9-δ)F_(0.1)(BCFZYF)and BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(2.9-δ)F_(0.1)(BZCYYbF)were synthesized for use as the cathode and electrolyte,respectively,in proton ceramic fuel cells.Our findings demonstrate that F-doped perovskite oxides exhibit superior electrochemical performance and enhanced structural stability.Furthermore,doping both electrodes and electrolytes with F ions improves their interfacial compatibility.The cell configuration BCFZYF|BZCYYbF|Ni-BZCYYbF achieved a peak power density of 998 mW·cm^(−2)at 650℃using H_(2)as fuel,and it maintained stable operation for over 400 h at 550℃with a current density of 400 mA·cm^(−2).This research underscores an effective strategy for enhancing the performance and durability of proton ceramic fuel cells.
基金Project supported by the National Key Research and Development Project (2018YFC1903400)the Jiangxi Province Graduate Student Innovation Special Fund Project (203200800389)+2 种基金the Natural Science Foundation of Jiangxi Province (20224BAB204038,20202BAB214014)the Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)the Open Project of Guangxi Key Laboratory of Nonferrous Metals and Characteristic Materials Processing(2022GXYSOF11)。
文摘Viewing the problem of high ene rgy consumption in the process of recovering rare earths from rare earth molten salt electrolysis slag,an environmentally friendly and low carbon process by sub-molten salt decomposition was developed.The thermodynamic analysis of sub-molten salt reaction indicates that the recovery of rare earths from the slag using sub-molten salt medium is thermodynamically feasible.In this process,the rare earth fluoride and lithium in the slag are almost transformed into rare earth hydroxide,sodium fluoride and lithium hydroxide,fluorine and lithium are transferred into the washing solution,and the rare earths in the residues can be leached into solution by acid leaching.Under the optimum reaction conditions of reaction temperature 200℃,reaction time 3 h,NaOH initial concentration 80%,NaOH-Slag mass ratio 3:1,the leaching efficiency of rare earths,fluorine and lithium can reach to 99.05%,98.23% and 99.22%.After evaporation,the fluorine and lithium in the washing solution can be obtained in the forms of sodium fluoride and lithium fluoride,the recovery efficiency reach 95.5%and 92.8%,respectively.The RE oxides(99.53%) can be obtained from the leaching solution after precipitation and roasting.
基金Project supported by the Qingjiang Excellent Young Talents of Jiangxi University of Science and Technology(JXUSTQJBJ2017004)Cultivation Program of State Key Laboratory for Green Development and High Value Utilization of Ionic Rare Earth Resources in Jiangxi Province(20194AFD44003)Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources of the People's Republic of China(2022IRERE305)。
文摘Rare earth fluoride molten-salt electrolytic slag(REFES)is a precious rare earth element(REE)secondary resource,and conside rable amounts of REEs exist in REFES as REF_(3);they are difficult to dissolve in acid or water and impede efficient REE extraction.In REFES recovery,the REF_(3)species in REFES are usually transformed into acid-soluble rare earth compounds by NaOH roasting or sulfating roasting and then extracted by acid leaching,Moreover,the fluorides in REFES are released as HF gas in the roasting process or enter the liquid phase during the water washing process;both of these processes cause fluorine pollution.Fixing the fluorine into the solid slag provides a way to avoid fluorine pollution.In this study,a novel method was proposed to extract REEs from REFES via MgCl_(2)roasting followed by HCl leaching.Thermodynamics calculations and the rmogravimetry-differential thermal analyses(TG-DTA)were conducted to investigate the reactions occurring in the roasting process,First,MgCl_(2)reacts with the REF_3and RE_(2)O_(3)to form RECl_(3)and REOCl,respectively.Second,the RECI_(3)absorbs water and forms RE(OH)_(3).Third,MgCl_(2)·6H_(2)O is gradually dehydrated to MgCl_(2)·2H_(2)O and reacts with REF_(3)and RE(OH)_(3),and REOCl,MgF_(2)and MgO are formed.Through HCl leaching,the REOCl in the roasting products is leached by HCl acid,while fluoride re mains in the solid slag as MgF_2.The optimum experimental conditions are as follows:mass ratio of MgCl_(2)to REFES of 30%,roasting temperature of 700℃,roasting time of 2 h,hydrochloride acid concentration of 4 mol/L,leaching time of 2 h,leaching temperature of 90℃and leaching L/S ratio of 20:1.The efficiencies for total leaching of the REEs,La,Ce,Pr,and Nd are 99.13%,99.20%,98.42%,99.38%,and 99.08%,respectively.Moreover,the concentration of fluoride in the leaching solution is 2.191×10^(-6)mol/L.This method has a short process flow with low reagent costs,and the problem of fluoride pollution from REFES recovery is solved;thus,our study has great industrial application potential.
基金financially supported by the National Natural Science Foundation of China(Nos.22225503,U21A20285 and 22375153)the Hubei Provincial Natural Science Foundation of China(No.2023AFA011)the Fundamental Research Funds for Central Universities(No.2042023kf0127)。
文摘Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2D)nets is a promising but underdeveloped strategy.Herein,we report the design and synthesis of a fluorine functionalized 3DCOF(3D-An-COF-F)formed by entangled 2D sql nets.The structure of 3D-An-COF-F was determined by the combination of continuous rotation electron diffraction technique and modelling based on the chemical information from real space.Interestingly,compared to the isostructural 3D-An-COF without F atom s,3DAn-COF-F showed an improved CO_(2)sorption ability and higher CO_(2)/N_(2)selectivity.Our study not only demonstrated the generality of constructing 3D COFs with entangled 2D nets by introducing bulky groups vertically in planar building blocks,but also will expand the diversity of 3D COFs for various applications.
文摘Because of the unique reactivity of sulfonyl fluoride(SO_(2)F)group,such compound has found increasing applications in the areas of organic synthesis,new drug development,pesticide,material science and click chemistry,etc.It is of current interest to develop novel strategies and methods for the facile preparation of sulfonyl fluorides in a green and highly efficient manner[1,2].Although the traditional approach for the synthesis of sulfonyl fluorides relies on the nucleophilic substitution of fluoride atom with sulfonyl chlorides.
文摘In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling pathway. This work reveals a highly complex conformational energy landscape of β-arrestin-1, and illuminates the molecular mechanism of the membrane phosphoinositide PIP2-induced β-arrestin-1 activation at residue level.(https://doi.org/10.1038/s41467-023-43694-1).
基金supported by the National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC)Tianjin Research Innovation Project for Postgraduate Students(2022SKYZ041).
文摘NH_(2)-MIL-125 is one of the most promising metal-organic frameworks(MOFs)for use as an adsorbent to remove nitrogen-containing compounds(NCCs)from fuels.In this study,NH_(2)-MIL-125 was further modified by loading the highly electronegative F and the heteropoly acid phosphomolybdic acid hydrate(PMA).Hydrogen bonds are suggested to form between F and PMA.X-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that the addition of these elements altered the morphology of NH_(2)-MIL-125,resulting in the growth of sectional octahedrons and cubes.The adsorptive denitrogenation(ADN)activity of 10%PMA@M125 was 1.7 times greater than that of NH_(2)-MIL-125 without F and PMA.The synergistic effect of F and PMA on the morphology and structure of NH_(2)-MIL-125 was examined,with a focus on different PMA contents.This study provides a simple method for modifying the morphology and structure of NH_(2)-MIL-125 by adding the required elements.
基金National Natural Science Foundation of China (Nos.21732002,22077071)Frontiers Science Center for New Organic Matter,Nankai University (No.63181206) for generous financial support for our programs。
文摘In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization(ISO) name during the last decade are described.The predominant approach for fluorine introduction of these agrochemicals is to use a fluorine-containing building block. Here we present how the fluorine-containing building blocks are introduced into these agrochemicals. The synthetic methods of fluorine-containing building blocks that are not easily available are also specifically discussed. Fluoroarenes, difluomethylarenes and trifluomethylarenes are the main building blocks that have been used in this review. Fluorine-containing small molecules, such as alcohol,amine, ketoester, olefin are also widely used. The only example of late-stage fluorination is the synthesis of fungicide quinofumelin. We believe the fluorine introduction methods described here can provide ideas for the development of new and economical pesticide synthetic routes, and stimulate researchers to develop new fluorine incorporation methods and create new pesticides.
基金the financial support provided by the National Natural Science Foundation of China(Nos.51932005,22072164)Liaoning Revitalization Talents Program(No.XLYC1807175)the Research Fund of Shenyang National Laboratory for Materials Science,the Natural Science Foundation of Jilin Province(Nos.YDZJ202301ZYTS280,YDZJ202201ZYTS305,YDZJ202401316ZYTS).
文摘Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides to optimize solid electrolyte interfaces and provide dynamic protection of electrodes to regulate the reaction and function performance of batteries.Nonetheless,the shuttle effect and the sluggish redox reaction kinetics emphasize the potential bottlenecks of lithium-sulfur batteries.Whether fluorine modulation regulate the reaction process of Li-S chemistry?Here,the TiOF/Ti_(3)C_(2)MXene nanoribbons with a tailored F distribution were constructed via an NH4F fluorinated method.Relying on in situ characterizations and electrochemical analysis,the F activates the catalysis function of Ti metal atoms in the consecutive redox reaction.The positive charge of Ti metal sites is increased due to the formation of O-Ti-F bonds based on the Lewis acid-base mechanism,which contributes to the adsorption of polysulfides,provides more nucleation sites and promotes the cleavage of S-S bonds.This facilitates the deposition of Li_(2)S at lower overpotentials.Additionally,fluorine has the capacity to capture electrons originating from Li_(2)S dissolution due to charge compensation mechanisms.The fluorine modulation strategy holds the promise of guiding the construction of fluorine-based catalysts and facilitating the seamless integration of multiple consecutive heterogeneous catalytic processes.
基金financially supported by the National Key R and D Program of China(No.2022YFB3805702)State Key Program of the National Natural Science Foundation of China(No.52130303)+1 种基金National Natural Science Foundation of China(Nos.51973152,51973119,5210309352173078)。
文摘Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of cation disorder can effectively suppress the detrimental two-phase reaction to realize high capacities in a wide voltage range.However,the continuous capacity decay during cycles has hindered the widespread application of these cathode materials.Inorganic fluorides exhibit excellent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially disordered spinel cathode(Li_(1.6)Mn_(1.6)O_(3.7)F_(0.3,)LMOF1.6)was initially applied to investigate the impacts of fluorination on the surface structure and electrochemical performances.The inorganic fluorinated layer,mainly containing LiF,was distributed uniformly on the surface of LMOF1.6nanoparticles after fluorination for an appropriate time without the turbulence caused by the valency of manganese cation,which improved the capacity retention and rate capability by the suppression of structural damage,parasitic reaction,and cation dissolution.The LMOF1.6cathode fluorinated for 0.5 h exhibited a capacity of283.6 mAh·g^(-1)at 50 mA·g^(-1)and an enhanced capacity retention of 29.6%after 50 cycles in the voltage range of1.5-4.8 V,as compared to the pristine LMOF1.6 with only27.9%capacity retention.
基金The authors are grateful for the support and funding from National Scientific Research Project(Basis Strengthening Plan)State Key Laboratory of Solidification Processing in NWPU(No.SKLSP202103).
文摘Bisphenol A dicyanate ester resins modified by fluorine-containing liquid crystal compound(LCFE)are applied as polymer matrix(LCFE-BADCy),poly(p-phenylene-2,6-benzobisoxazole)(PBO)fibers as rein-forcements,and fluorine/adamantane PBO precursor(pre FABPBO)as interfacial compatibilizer to prepare the corresponding PBO fibers/FABPBO/LCFE-BADCy wave-transparent laminated composites.LCFE could improve the order degree of BADCy cured network,in favor of enhancing the wave-transparent perfor-mance,mechanical properties,and intrinsic thermal conductivity.The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature(25–200℃)and frequency(10^(4)–10^(7) Hz and 8.2–12.4 GHz)stable with the value of 2.49 and 0.003 under 10^(6) Hz at 25℃,and the corresponding wave transmission efficiency is 95.0%,higher than that of 92.5%for PBO fibers/BADCy com-posites.The interlamellar shear strength and flexural strength are respectively 50.7 MPa and 682.5 MPa,38.1%and 16.2%higher than those of PBO fibers/BADCy composites.Besides,the volume resistivity,breakdown voltage,heat resistance index,glass transition temperature,flame retardant grade,and ul-timate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×10^(15)Ωcm,29.75 kV/mm,217.2℃,245.7℃,V-1 grade,and 33.6%,expected to be performed as a new generation of“lightweight/loading/wave-transparent”electromagnetic window materials in advanced military weapons and civil communication base station.
文摘The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.
基金Project 2001KJ11 supported by National investigation of land and resources
文摘Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test results of 36 groundwater samples show that fluorine concentration in shallow groundwater is 0.18–6.7 mg/L and 50 % of the samples exceed the Chinese drinking water quality standard. There exists a significant negative correlation in content between Ca2+ and F - . The correlations between fluorine concentration and other cations (for example Na+, K+, Mg2+) are not significant. The content of dissolved fluorine from the flooding sediments of the Huanghe River that varying from 5.6 mg/kg to 15.2 mg/kg plays an important role in forming the high fluorine groundwater. Usually, the dissolved fluorine content in silt is much higher than that in silty clay and clay. According to the geological investigation fluorine content in deep groundwater (over 60 m) is less than 1.0 mg/L and suitable for drinking, so it is an effective measure to prevent endemic fluorosis by extracting deep groundwater in disease areas.
基金"973 Program"(2006CB202202)The National Natural Science Foundation of China(40572090,40272124)
文摘A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrence and accumulation of the F in coals and its potential hazard to human and environment. Analytical data of coal samples were referred to study the great difference of the F content between coals and gangue. The results show that the average value of the F in the coal samples collected in different coalfields of China is 304x10^6, while that of gangue samples is surprisingly 1 319x10^6, especially the F content of coal ash from Bangmai in Yunnan Province reaches 4 800x10^6. It has been proved in many provinces of China that burning the coal and clay mixture can produce F contamination.
