In this study,fluorinating vaporization combined with ETV-ICP-AES technique was used to determine yttrium for which refractory carbide is easily formed.The absolute detection limit is 12 pg,and three-order magnitude o...In this study,fluorinating vaporization combined with ETV-ICP-AES technique was used to determine yttrium for which refractory carbide is easily formed.The absolute detection limit is 12 pg,and three-order magnitude of improvement is obtained in comparison with the conventional vaporization ETV-ICP-AES.No memory effect is observed.The relative standard deviation is better than 5%.Some factors affecting fluorinating vaporization,including matrix effect are discussed.This technique is applied to determine yttrium in La_2O_3.展开更多
Treatment of N-t-butylbenzenesulfonamide with an excess of BuLi, followed by the reaction with methyl 2-（4-methylphenyl）propanoate, gave the corresponding 2-carboxybenzenesulfonamide, which underwent a sequence of c...Treatment of N-t-butylbenzenesulfonamide with an excess of BuLi, followed by the reaction with methyl 2-（4-methylphenyl）propanoate, gave the corresponding 2-carboxybenzenesulfonamide, which underwent a sequence of consecutive N-deprotective cyclization process mediated by TMSCI-NaI-MeCN reagent to afford the N-sulfonylimine. Following the bromination and ring expansion, 3-methyl-3-（4-methylphenyl）-2H-benzo[e][1,2]thiazine-l,l,4-trione was obtained. Optical resolution of the racemic benzosultam using （-）-menthoxyacetyl chloride, furnished the optically p.ure （＋）- and （-）-3-methyl-3-（4-methylphenyl）-2H- benzo[e][1,2]thiazine-1,1,4-triones, which were fluorinated with FC103 to produce the corresponding chiral N-F agents.展开更多
The direct preparation of a kind of fluorinating reagent 1[F-TEDA-N(SO_(2)Ph)_(2)]was realized in high yield via the complexation of N-fluorobenzenesulfonimide(NFSI)with 1-(chloromethyl)-1,4-diazabicyclo[2.2.2]octan-1...The direct preparation of a kind of fluorinating reagent 1[F-TEDA-N(SO_(2)Ph)_(2)]was realized in high yield via the complexation of N-fluorobenzenesulfonimide(NFSI)with 1-(chloromethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium N',N'-bis-(benzenesulfonylimide)salt.In its fluorination to oxindoles,the fluorinating products 6 were afforded in moderate to high yields.展开更多
The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,...The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.展开更多
With the miniaturization and high-frequency evolution of antennas in 5G/6G communications,aerospace,and transportation,polymer composite papers integrating superior wave-transparent performance and thermal conductivit...With the miniaturization and high-frequency evolution of antennas in 5G/6G communications,aerospace,and transportation,polymer composite papers integrating superior wave-transparent performance and thermal conductivity for radar antenna systems are urgently needed.Herein,a down-top strategy was employed to synthesize poly(p-phenylene benzobisoxazole)precursor nanofibers(prePNF).The prePNF was then uniformly mixed with fluorinated graphene(FG)to fabricate FG/PNF composite papers through consecutively suction filtration,hot-pressing,and thermal annealing.The hydroxyl and amino groups in prePNF enhanced the stability of FG/prePNF dispersion,while the increasedπ-πinteractions between PNF and FG after annealing improved their compatibility.The preparation time and cost of PNF paper was significantly reduced when applying this strategy,which enabled its large-scale production.Furthermore,the prepared FG/PNF composite papers exhibited excellent wave-transparent performance and thermal conductivity.When the mass fraction of FG was 40 wt%,the FG/PNF composite paper prepared via the down-top strategy achieved the wave-transparent coefficient(|T|2)of 96.3%under 10 GHz,in-plane thermal conductivity(λ_(∥))of 7.13 W m^(−1)K^(−1),and through-plane thermal conductivity(λ_(⊥))of 0.67 W m^(−1)K^(−1),outperforming FG/PNF composite paper prepared by the top-down strategy(|T|2=95.9%,λ_(∥)=5.52 W m^(−1)K^(−1),λ_(⊥)=0.52 W m^(−1)K^(−1))and pure PNF paper(|T|2=94.7%,λ_(∥)=3.04 W m^(−1)K^(−1),λ_(⊥)=0.24 W m^(−1)K^(−1)).Meanwhile,FG/PNF composite paper(with 40 wt%FG)through the down-top strategy also demonstrated outstanding mechanical properties with tensile strength and toughness reaching 197.4 MPa and 11.6 MJ m^(−3),respectively.展开更多
Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.H...Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.展开更多
Polymer-electrolyte-based solid-state Li metal batteries with high-voltage Ni-rich cathodes are promising energy storage technologies owing to their favorable security and high energy densities.However,operating in wi...Polymer-electrolyte-based solid-state Li metal batteries with high-voltage Ni-rich cathodes are promising energy storage technologies owing to their favorable security and high energy densities.However,operating in wide temperature range and at high voltage is a tough challenge for them.Herein,F/N donating fluorinated-amide-based plasticizers regulated polymer electrolyte capable of enabling high-voltage Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)batteries with excellent performance in wide temperature range is developed.F/N donating fluorinated-amide-based plasticizers significantly improve ionic conductivity(1.52 mS/cm at 30℃),enhance oxidation stability(5.0 V vs.Li^(+)/Li)and fabricate robust LiF/Li_(3)N-rich electrode-electrolyte interphases,which significantly improve the interface stability of Li metal anode and NCM811 cathode.The designed polymer electrolyte is nonflammable and has excellent dimensional stability at 200℃.Capitalizing on these advantageous attributes,the Li||NCM811 cells show excellent cycle stability and rate capability from−20℃ to 60℃ at high voltages(∼4.6 V),and under high-loading full cell condition,which display impressive capacity retention of 84.4%after 1000 cycles and ultrahigh capacity of 154.8 mAh/g at 10 C.This work provides a rational design strategy of polymer electrolytes for wide-temperature high-energy solid-state Li metal batteries.展开更多
In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still face...In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.展开更多
The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impac...The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.展开更多
Crystallized lithium fluoride(LiF)melts at 848℃ upon heating,and evaporates subsequently at a remarkably high temperature of 1673℃,characterizing its excellent thermally stability as one of the most representative m...Crystallized lithium fluoride(LiF)melts at 848℃ upon heating,and evaporates subsequently at a remarkably high temperature of 1673℃,characterizing its excellent thermally stability as one of the most representative metal halides.The marriage between Li F and rechargeable batteries dates back to early activities related to the electrochemical properties of lithium metal(Li°)negative electrodes,in which the nonaqueous electrolytes containing fluorinated salts were generally employed,e.g.,lithium tetrafluoroborate(LiBF_(4)),lithium hexafluoroarsenate(LiAsF_(6)),lithium trifluoromethanesulfonate(CF_(3)SO_(3)Li)[1].展开更多
The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation...The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.展开更多
The presence of aluminum(Al^(3+))and fluoride(F^(−))ions in the environment can be harmful to ecosystems and human health,highlighting the need for accurate and efficient monitoring.In this paper,an innovative approac...The presence of aluminum(Al^(3+))and fluoride(F^(−))ions in the environment can be harmful to ecosystems and human health,highlighting the need for accurate and efficient monitoring.In this paper,an innovative approach is presented that leverages the power of machine learning to enhance the accuracy and efficiency of fluorescence-based detection for sequential quantitative analysis of aluminum(Al^(3+))and fluoride(F^(−))ions in aqueous solutions.The proposed method involves the synthesis of sulfur-functionalized carbon dots(C-dots)as fluorescence probes,with fluorescence enhancement upon interaction with Al^(3+)ions,achieving a detection limit of 4.2 nmol/L.Subsequently,in the presence of F^(−)ions,fluorescence is quenched,with a detection limit of 47.6 nmol/L.The fingerprints of fluorescence images are extracted using a cross-platform computer vision library in Python,followed by data preprocessing.Subsequently,the fingerprint data is subjected to cluster analysis using the K-means model from machine learning,and the average Silhouette Coefficient indicates excellent model performance.Finally,a regression analysis based on the principal component analysis method is employed to achieve more precise quantitative analysis of aluminum and fluoride ions.The results demonstrate that the developed model excels in terms of accuracy and sensitivity.This groundbreaking model not only showcases exceptional performance but also addresses the urgent need for effective environmental monitoring and risk assessment,making it a valuable tool for safeguarding our ecosystems and public health.展开更多
All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercializat...All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercialization of ASSLBs still faces challenges regarding the electrolyte/electrodes interfaces and growth of Li dendrites.Elemental doping is an effective and direct method to enhance the performance of SEs.Here,we report an Al-F co-doping strategy to improve the overall properties including ion conductivity,high voltage stability,and cathode and anode compatibility.Particularly,the Al-F co-doping enables the formation of a thin Li-Al alloy layer and fluoride interphases,thereby constructing a relatively stable interface and promoting uniform Li deposition.The similar merits of Al-F co-doping are also revealed in the Li-argyrodite series.ASSLBs assembled with these optimized electrolytes gain good electrochemical performance,demonstrating the universality of Al-F co-doping towards advanced SEs.展开更多
Fluorinated gases(F-gases)play a vital role in the chemical industry and in the fields of air conditioning,refrigeration,health care,and organic synthesis.However,the direct emission of waste gases containing F-gases ...Fluorinated gases(F-gases)play a vital role in the chemical industry and in the fields of air conditioning,refrigeration,health care,and organic synthesis.However,the direct emission of waste gases containing F-gases into the atmosphere contributes to greenhouse effects and generates toxic substances.Developing porous materials for the energy-efficient capture,separation,and recovery of F-gases is highly desired.Recently,as a highly designable porous adsorbents,metal–organic frameworks(MOFs)exhibit excellent selective sorption performance toward F-gases,especially for the recognition and separation of different F-gases with highly similar properties,showing their great potential in F-gases control and recovery.In this review,we discuss the capture and separation of F-gases and their azeotropic,near-azeotropic,and isomeric mixtures in various application scenarios by MOFs,specifically classify and analyze molecular interaction between F-gases and MOFs,and interpret the mechanisms underlying their high performance regarding both adsorption capacity and selectivity,providing a repertoire for future materials design.Challenges faced in the transformation research roadmap of MOFs adsorbent separation technologies toward F-gases are also discussed,and areas for future research endeavors are highlighted.展开更多
In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that wit...In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that with the increasing of F content,the toluene conversion rate first increased and then decreased.However,CO_(2)mineralization efficiency showed the opposite trend.Based on the characterizations,we revealed that F substitutes the surface hydroxyl of TiO_(2)to form the structure of≡Ti-F.The presence of the appropriate amount of surface≡Ti-F on TiO_(2)greatly enhanced the separation of photogenerated carriers,which facilitated the generation of·OH and promoted the activity for the PCO of toluene.It was further revealed that the increase of only·OH promoted the conversion of toluene to ring-containing intermediates,causing the accumulation of intermediates and then conversely inhibited the·OH generation,which led to the decrease of the CO_(2)mineralization efficiency.The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.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
Fluoride-based electrolyte exhibits extraordinarily high oxidative stability in high-voltage lithium metal batteries(h-LMBs) due to the inherent low highest occupied molecular orbital(HOMO) of fiuorinated solvents. Ho...Fluoride-based electrolyte exhibits extraordinarily high oxidative stability in high-voltage lithium metal batteries(h-LMBs) due to the inherent low highest occupied molecular orbital(HOMO) of fiuorinated solvents. However, such fascinating properties do not bring long-term cyclability of h-LMBs. One of critical challenges is the interface instability in contacting with the Li metal anode, as fiuorinated solvents are highly susceptible to exceptionally reductive metallic Li attributed to its low lowest unoccupied molecular orbital(LUMO), which leads to significant consumption of the fiuorinated components upon cycling.Herein, attenuating reductive decomposition of fiuorinated electrolytes is proposed to circumvent rapid electrolyte consumption. Specifically, the vinylene carbonate(VC) is selected to tame the reduction decomposition by preferentially forming protective layer on the Li anode. This work, experimentally and computationally, demonstrates the importance of pre-passivation of Li metal anodes at high voltage to attenuate the decomposition of fiuoroethylene carbonate(FEC). It is expected to enrich the understanding of how VC attenuate the reactivity of FEC, thereby extending the cycle life of fiuorinated electrolytes in high-voltage Li-metal batteries.展开更多
X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorpho...X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.展开更多
Practical application of Na_(3)SbS_(4)(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 ...Practical application of Na_(3)SbS_(4)(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
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
文摘In this study,fluorinating vaporization combined with ETV-ICP-AES technique was used to determine yttrium for which refractory carbide is easily formed.The absolute detection limit is 12 pg,and three-order magnitude of improvement is obtained in comparison with the conventional vaporization ETV-ICP-AES.No memory effect is observed.The relative standard deviation is better than 5%.Some factors affecting fluorinating vaporization,including matrix effect are discussed.This technique is applied to determine yttrium in La_2O_3.
基金the Scientific Research Foundation for the Returned Oversea Chinese Scholars of Shandong University.
文摘Treatment of N-t-butylbenzenesulfonamide with an excess of BuLi, followed by the reaction with methyl 2-（4-methylphenyl）propanoate, gave the corresponding 2-carboxybenzenesulfonamide, which underwent a sequence of consecutive N-deprotective cyclization process mediated by TMSCI-NaI-MeCN reagent to afford the N-sulfonylimine. Following the bromination and ring expansion, 3-methyl-3-（4-methylphenyl）-2H-benzo[e][1,2]thiazine-l,l,4-trione was obtained. Optical resolution of the racemic benzosultam using （-）-menthoxyacetyl chloride, furnished the optically p.ure （＋）- and （-）-3-methyl-3-（4-methylphenyl）-2H- benzo[e][1,2]thiazine-1,1,4-triones, which were fluorinated with FC103 to produce the corresponding chiral N-F agents.
基金the National Natural Science Foundation of China(No.21372077)for their financial supports.
文摘The direct preparation of a kind of fluorinating reagent 1[F-TEDA-N(SO_(2)Ph)_(2)]was realized in high yield via the complexation of N-fluorobenzenesulfonimide(NFSI)with 1-(chloromethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium N',N'-bis-(benzenesulfonylimide)salt.In its fluorination to oxindoles,the fluorinating products 6 were afforded in moderate to high yields.
基金supported by the National Natural Science Foundation of China(22378205)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Center for Advanced Materials and Technology in Nanjing University of Science and Technology。
文摘The incorporation of small fluorinated functional groups,including CF_(3),CF_(2)H,and CFH_(2),into small molecules represents a crucial strategy for modulating their physical,chemical,and biological characteristics[1,2].Consequently,organofluorine compounds are frequently encountered in pharmaceuticals and agrochemicals.Significant advances have been made in the introduction of fluoroalkyl groups into small molecules since the beginning of the 21st century.
基金the support from the National Natural Science Foundation of China(52473083,52373089,52403085)Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)+2 种基金the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57)Natural Science Basic Research Plan in Shaanxi Province of China(2024JC-YBMS-279)Natural Science Foundation of Chongqing,China(2023NSCQMSX2547)
文摘With the miniaturization and high-frequency evolution of antennas in 5G/6G communications,aerospace,and transportation,polymer composite papers integrating superior wave-transparent performance and thermal conductivity for radar antenna systems are urgently needed.Herein,a down-top strategy was employed to synthesize poly(p-phenylene benzobisoxazole)precursor nanofibers(prePNF).The prePNF was then uniformly mixed with fluorinated graphene(FG)to fabricate FG/PNF composite papers through consecutively suction filtration,hot-pressing,and thermal annealing.The hydroxyl and amino groups in prePNF enhanced the stability of FG/prePNF dispersion,while the increasedπ-πinteractions between PNF and FG after annealing improved their compatibility.The preparation time and cost of PNF paper was significantly reduced when applying this strategy,which enabled its large-scale production.Furthermore,the prepared FG/PNF composite papers exhibited excellent wave-transparent performance and thermal conductivity.When the mass fraction of FG was 40 wt%,the FG/PNF composite paper prepared via the down-top strategy achieved the wave-transparent coefficient(|T|2)of 96.3%under 10 GHz,in-plane thermal conductivity(λ_(∥))of 7.13 W m^(−1)K^(−1),and through-plane thermal conductivity(λ_(⊥))of 0.67 W m^(−1)K^(−1),outperforming FG/PNF composite paper prepared by the top-down strategy(|T|2=95.9%,λ_(∥)=5.52 W m^(−1)K^(−1),λ_(⊥)=0.52 W m^(−1)K^(−1))and pure PNF paper(|T|2=94.7%,λ_(∥)=3.04 W m^(−1)K^(−1),λ_(⊥)=0.24 W m^(−1)K^(−1)).Meanwhile,FG/PNF composite paper(with 40 wt%FG)through the down-top strategy also demonstrated outstanding mechanical properties with tensile strength and toughness reaching 197.4 MPa and 11.6 MJ m^(−3),respectively.
基金supported by the National Key R&D Program of China(No.2022YFB3803400)National Natural Science Foundation of China(Nos.52102054,52020105010,51927803,52188101 and 52072378)+1 种基金Liaoning Province Science and Technology Planning Project(No.2022-BS-007)Fujian Science and Technology Program(No.2023T3025).
文摘Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.
基金supported by the Science Foundation of High-Level Talents of Wuyi University(Nos.2019AL017,2021AL002).
文摘Polymer-electrolyte-based solid-state Li metal batteries with high-voltage Ni-rich cathodes are promising energy storage technologies owing to their favorable security and high energy densities.However,operating in wide temperature range and at high voltage is a tough challenge for them.Herein,F/N donating fluorinated-amide-based plasticizers regulated polymer electrolyte capable of enabling high-voltage Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)batteries with excellent performance in wide temperature range is developed.F/N donating fluorinated-amide-based plasticizers significantly improve ionic conductivity(1.52 mS/cm at 30℃),enhance oxidation stability(5.0 V vs.Li^(+)/Li)and fabricate robust LiF/Li_(3)N-rich electrode-electrolyte interphases,which significantly improve the interface stability of Li metal anode and NCM811 cathode.The designed polymer electrolyte is nonflammable and has excellent dimensional stability at 200℃.Capitalizing on these advantageous attributes,the Li||NCM811 cells show excellent cycle stability and rate capability from−20℃ to 60℃ at high voltages(∼4.6 V),and under high-loading full cell condition,which display impressive capacity retention of 84.4%after 1000 cycles and ultrahigh capacity of 154.8 mAh/g at 10 C.This work provides a rational design strategy of polymer electrolytes for wide-temperature high-energy solid-state Li metal batteries.
基金the financial support from the National Natural Science Foundation of China (No. 52072390)the National High-Level Talents Special Support Program (Leading Talent of Technological Innovation)+2 种基金the China Postdoctoral Science Foundation (No. 2023M743648)the Young Scientists Fund of the National Natural Science Foundation of China (No. 52302330)the support from the Shanghai Emperor of Cleaning Hi-Tech Co.,LTD
文摘In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.
基金financially supported by the National Natural Science Foundation of China (Nos.22375024,21975031,51933001,and 21734009)。
文摘The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.
文摘Crystallized lithium fluoride(LiF)melts at 848℃ upon heating,and evaporates subsequently at a remarkably high temperature of 1673℃,characterizing its excellent thermally stability as one of the most representative metal halides.The marriage between Li F and rechargeable batteries dates back to early activities related to the electrochemical properties of lithium metal(Li°)negative electrodes,in which the nonaqueous electrolytes containing fluorinated salts were generally employed,e.g.,lithium tetrafluoroborate(LiBF_(4)),lithium hexafluoroarsenate(LiAsF_(6)),lithium trifluoromethanesulfonate(CF_(3)SO_(3)Li)[1].
基金supported by the National Natural Science Foundation of China (Grant Nos. 62174019, 52302046, L2424216)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2024A1515012139)+2 种基金the Major Program (JD) of Hubei Province (Grant No. 2023BAA009)the Knowledge Innovation Program of Wuhan-Shuguang Project (Grant No. 2023010201020262)the Basic Research Program of Jiangsu (Grant No. BK20230268)。
文摘The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.
基金supported by the National Natural Science Foundation of China(No.U21A20290)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011656)+2 种基金the Projects of Talents Recruitment of GDUPT(No.2023rcyj1003)the 2022“Sail Plan”Project of Maoming Green Chemical Industry Research Institute(No.MMGCIRI2022YFJH-Y-024)Maoming Science and Technology Project(No.2023382).
文摘The presence of aluminum(Al^(3+))and fluoride(F^(−))ions in the environment can be harmful to ecosystems and human health,highlighting the need for accurate and efficient monitoring.In this paper,an innovative approach is presented that leverages the power of machine learning to enhance the accuracy and efficiency of fluorescence-based detection for sequential quantitative analysis of aluminum(Al^(3+))and fluoride(F^(−))ions in aqueous solutions.The proposed method involves the synthesis of sulfur-functionalized carbon dots(C-dots)as fluorescence probes,with fluorescence enhancement upon interaction with Al^(3+)ions,achieving a detection limit of 4.2 nmol/L.Subsequently,in the presence of F^(−)ions,fluorescence is quenched,with a detection limit of 47.6 nmol/L.The fingerprints of fluorescence images are extracted using a cross-platform computer vision library in Python,followed by data preprocessing.Subsequently,the fingerprint data is subjected to cluster analysis using the K-means model from machine learning,and the average Silhouette Coefficient indicates excellent model performance.Finally,a regression analysis based on the principal component analysis method is employed to achieve more precise quantitative analysis of aluminum and fluoride ions.The results demonstrate that the developed model excels in terms of accuracy and sensitivity.This groundbreaking model not only showcases exceptional performance but also addresses the urgent need for effective environmental monitoring and risk assessment,making it a valuable tool for safeguarding our ecosystems and public health.
基金supported by the National Natural Science Foundation of China(Nos.52172243,52371215)。
文摘All-solid-state Li batteries(ASSLBs)using solid electrolytes(SEs)have gained significant attention in recent years considering the safety issue and their high energy density.Despite these advantages,the commercialization of ASSLBs still faces challenges regarding the electrolyte/electrodes interfaces and growth of Li dendrites.Elemental doping is an effective and direct method to enhance the performance of SEs.Here,we report an Al-F co-doping strategy to improve the overall properties including ion conductivity,high voltage stability,and cathode and anode compatibility.Particularly,the Al-F co-doping enables the formation of a thin Li-Al alloy layer and fluoride interphases,thereby constructing a relatively stable interface and promoting uniform Li deposition.The similar merits of Al-F co-doping are also revealed in the Li-argyrodite series.ASSLBs assembled with these optimized electrolytes gain good electrochemical performance,demonstrating the universality of Al-F co-doping towards advanced SEs.
基金funded by the National Key Research and Development Program of China(2022YFE0110500)National Natural Science Foundation of China(22376161,52373154,52103181)+1 种基金the Fundamental Research Funds for the Central Universities of Chinathe Interdisciplinary Project in Environmental Science and Engineering of Tongji University(2023-3-YB-02)。
文摘Fluorinated gases(F-gases)play a vital role in the chemical industry and in the fields of air conditioning,refrigeration,health care,and organic synthesis.However,the direct emission of waste gases containing F-gases into the atmosphere contributes to greenhouse effects and generates toxic substances.Developing porous materials for the energy-efficient capture,separation,and recovery of F-gases is highly desired.Recently,as a highly designable porous adsorbents,metal–organic frameworks(MOFs)exhibit excellent selective sorption performance toward F-gases,especially for the recognition and separation of different F-gases with highly similar properties,showing their great potential in F-gases control and recovery.In this review,we discuss the capture and separation of F-gases and their azeotropic,near-azeotropic,and isomeric mixtures in various application scenarios by MOFs,specifically classify and analyze molecular interaction between F-gases and MOFs,and interpret the mechanisms underlying their high performance regarding both adsorption capacity and selectivity,providing a repertoire for future materials design.Challenges faced in the transformation research roadmap of MOFs adsorbent separation technologies toward F-gases are also discussed,and areas for future research endeavors are highlighted.
基金supported by the National Natural Science Foundation of China(Nos.21976196,22276204).
文摘In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that with the increasing of F content,the toluene conversion rate first increased and then decreased.However,CO_(2)mineralization efficiency showed the opposite trend.Based on the characterizations,we revealed that F substitutes the surface hydroxyl of TiO_(2)to form the structure of≡Ti-F.The presence of the appropriate amount of surface≡Ti-F on TiO_(2)greatly enhanced the separation of photogenerated carriers,which facilitated the generation of·OH and promoted the activity for the PCO of toluene.It was further revealed that the increase of only·OH promoted the conversion of toluene to ring-containing intermediates,causing the accumulation of intermediates and then conversely inhibited the·OH generation,which led to the decrease of the CO_(2)mineralization efficiency.The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.
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 the National Natural Science Foundation of China (Nos. 22379121, 62005216)Basic Public Welfare Research Program of Zhejiang (No. LQ22F050013)+1 种基金Zhejiang Province Key Laboratory of Flexible Electronics Open Fund (2023FE005)Shenzhen Foundation Research Program (No. JCYJ20220530112812028)。
文摘Fluoride-based electrolyte exhibits extraordinarily high oxidative stability in high-voltage lithium metal batteries(h-LMBs) due to the inherent low highest occupied molecular orbital(HOMO) of fiuorinated solvents. However, such fascinating properties do not bring long-term cyclability of h-LMBs. One of critical challenges is the interface instability in contacting with the Li metal anode, as fiuorinated solvents are highly susceptible to exceptionally reductive metallic Li attributed to its low lowest unoccupied molecular orbital(LUMO), which leads to significant consumption of the fiuorinated components upon cycling.Herein, attenuating reductive decomposition of fiuorinated electrolytes is proposed to circumvent rapid electrolyte consumption. Specifically, the vinylene carbonate(VC) is selected to tame the reduction decomposition by preferentially forming protective layer on the Li anode. This work, experimentally and computationally, demonstrates the importance of pre-passivation of Li metal anodes at high voltage to attenuate the decomposition of fiuoroethylene carbonate(FEC). It is expected to enrich the understanding of how VC attenuate the reactivity of FEC, thereby extending the cycle life of fiuorinated electrolytes in high-voltage Li-metal batteries.
基金supported by the National Natural Science Foundation of China(No.12235006)the National Key Research and Development Program of China(No.2020YFE0202002.
文摘X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.
文摘Practical application of Na_(3)SbS_(4)(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.
