Phosphate Anions Research Articles

The amputation of phosphate anions by cobalt oxide nanoparticles doped functionalized nanocomposites from wastewater

As a novel adsorbent to removal phosphate from water, Co3O4 magnetic nanoparticles functionalized with zeolite-A-@silica nanocomposites were created. The produced adsorbent was evaluated for phosphate removal efficiency using batch adsorption tests, as well as X-ray diffractometry (XRD), scanning electron microscopy (SEM), EDX, BET, and FT-IR. The synthesized adsorbent with a BET (Brunauer–Emmett–Teller(BET) surface area of 8.367 m2/g, porous zeolite-A, was successfully constructed with Co3O4 and nanosilica, according to characterization results. The newly created adsorbent performed incredibly well at adsorbing phosphate; according to the Langmuir model, it had a maximum adsorption capacity of 344.83 mg/g. The adsorption occurred quickly, and the pseudo-first-order kinetic model provided the greatest fit for the kinetic data. As the pH of the solution increased (2 to 10), the elimination of phosphate reduced. The experimental results indicated negative ΔG, negative ΔH, and positive S, suggesting the exothermic and spontaneous process of PO4-3 adsorption on synthesized adsorbents.

Ultrasensitive NIR fluorometric assay for inorganic pyrophosphatase detection via Cu2+-PPi interaction using bimetallic Au–Ag nanoclusters

BackgroundInorganic pyrophosphatase (PPase) is key enzyme playing a key role in biochemical transformations such as biosynthesis of DNA and RNA, bone formation, metabolic pathways associated with lipid, carbohydrate and phosphorous. It has been reported that lung adenocarcinomas, colorectal cancer, and hyperthyroidism disorders can result from abnormal level of PPase. Therefore, it is of notable significance to develop simple and effective real time assay for PPase enzyme activity monitoring for screening of many metabolic pathways as well as for early disease diagnosis. ResultThe fluorometric detection of PPase enzyme in near infrared region-1 (NIR-1) has been carried out using bimetallic nanoclusters (LA@AuAg NCs). The developed sensing strategy was based on quenching of fluorescence intensity of LA@AuAg NCs upon interaction with copper (Cu2+) ions. The off state of LA@AuAg_Cu2+ ensemble was turned on upon addition of pyrophosphate anion (PPi) due to strong binding interaction between PPi and Cu2+. The catalytic conversion of PPi into phosphate anion (Pi) in the presence of PPase led to liberation of Cu2+ ions, and again quenched off state was retrieved due to interaction of free Cu2+ with LA@AuAg NCs. The ultrasensitive detection of PPase was observed in the linear range of 0.06–250 mU/mL with LOD as 0.0025 mU/mL. The designed scheme showed good selectivity towards PPase enzyme in comparison to other bio-substrates, along with good percentage recovery for PPase detection in real human serum samples. SignificanceThe developed NIR based assay is ultrasensitive, highly selective and robust for PPase enzyme and can be safely employed for other enzymes detection. This highly sensitive nature of biosensor was result of involvement of fluorescence-based technique and synergistic effect of dual metal in NIR based bimetallic NCs. Moreover, owing to the emission in NIR domain, in future, these nanoclusters can be safely employed for many biomedical applications for In vivo studies.

Aqueous phosphate detection in real samples using NIR-triggered Diamino Bis-Benzimidazoquinoline fluorescence sensor: An experimental and theoretical approach

The present work reports the design, synthesis, and sensing applications of Diamino bis-benzimidazoquinoline (DA-BISQ) derivatives. These compounds were synthesized in appreciable yield and characterized by FT-IR, 1H, and 13C NMR spectral and mass spectrometry. Optical studies revealed intriguing dual excitation properties: single excitations at λex 330-386 nm and double excitations at λex 660-772 nm in 10 % ethanol-water medium. The near-infrared excitation region λex 660-772 nm was particularly focused on the detection of F¯, Cl¯, Br¯, I¯, AcO ̄, ClO4¯, NO3¯, and HPO4¯ anions. Notably, selective fluorescence quenching "OFF" responses were observed for geometric anions like AcO¯, ClO4¯, NO3¯, and HPO4¯. Interestingly, the pyridine spacer-containing derivative 1c exhibited a unique fluorescence "OFF-ON'' response for the phosphate ion. Cyclic voltammetry titration further corroborated the binding affinity towards phosphate. To demonstrate practical applicability, a thin-film strip of receptor 1c was fabricated and tested for effective phosphate sensing in human blood serum samples. Density functional theory calculations were performed to elucidate the sensing mechanism with the phosphate anion. The combined experimental and theoretical results suggest an internal charge transfer process between the receptor and the anion.

Microscale heterogeneity of phosphorus species associated with secondary mineral phases in the B horizons of two boreal Podzols

Poorly crystalline Al and Fe minerals have high sorption capacities for phosphate anions. However, there is still uncertainty about the molecular-level distribution of phosphorus (P) species between Al and Fe mineral phases, which can be relevant for bioavailability. The present study employed synchrotron X-ray microscopic techniques to distinguish between Al- and Fe-associated P phases in two Podzol B horizons (Flakaliden and Skogaby). First, P species were clustered into major groups depending on the main element association (Al-P, Fe-P, Ca-P + organic P) according to the color of P-containing spots in the tricolor μ-XRF quantitative maps that combined P, Al, and Fe fluorescence intensities. Second, the results were analyzed using quantitative linear combination fitting (LCF) of the P K-edge μ-XANES spectra. Third, in cases when the results diverged, a careful visual comparison between the diagnostic features of the XANES spectra of the samples and the reference standards was made. In 45 of 54 investigated spots, the color method and XANES-LCF produced consistent results. In 2 spots where the results were inconsistent, the diagnostic features of the XANES spectra agreed with the color method but not with XANES-LCF. In 39 of the 47 spots where the major P phase could be identified, Al-P was found to predominate. Ca-P was the major phase in 5 spots, Fe-P in 2, and organic P in 1. Most of the Al-P probably consisted of PO4 adsorbed to imogolite-type materials (ITM), as evidenced by oxalate extraction and Fourier Transform Infrared (FTIR) spectroscopy, although at Skogaby, adsorbed organic P may have played an important additional role. Overall, the P speciation showed substantial spatial heterogeneity, particularly in the upper B horizon of the Skogaby soil and in the lower B horizon of the Flakaliden soil. In conclusion, Al-P, particularly ITM-adsorbed PO4, is the main P phase in the B horizons of the studied Podzols, which may have implications for bioavailability as ITM is more easily dissolved than Fe oxides. Also, the combination of XANES-LCF, colors of the μ-XRF maps, and diagnostic features of the XANES spectra led to robust estimates of the major P phases in soil microsites.

4-Carboxyanilinium dihydrogen phosphate monohydrate, an organophosphate adducts of 4-amino benzoic acid: Structural, vibrational, thermal, and computational studies

4-Carboxyanilinium dihydrogen phosphate monohydrate (4-CAH2PO4·H2O), an organophosphate adduct, was synthesized and characterized by single-crystal X-ray diffraction, Fourier transform infrared (FTIR), Differential scanning calorimetry (DSC) and computational analysis performed using CrystalExplorer 21, Gaussian 09W and Multiwfn 3.7 software. The complex 4-CAH2PO4·H2O crystallized in the triclinic space group, P-1, with two molecules each of 4-carboxyanilinium (4-CA) cations, H2PO4– anions, and water, respectively, in an asymmetric unit. Crystal data for C7H12NO7P: triclinic, space group P-1, a = 8.5238(2) Å, b = 8.9068(2) Å, c = 14.4976(4) Å, α = 106.456(2)°, β = 90.195(2)°, γ = 92.811(2)°, V = 1054.13(5) Å3, Z = 4, T = 293 K, μ(Cu Kα) = 2.587 mm-1, Dcalc = 1.595 g/cm3, 18182 reflections measured (6.358° ≤ 2Θ ≤ 146.396°), 4149 unique (Rint = 0.1018, Rsigma = 0.0521) which were used in all calculations. The final R1 was 0.0584 (I > 2σ(I)) and wR2 was 0.1712 (all data). The organic layer containing 4-CA cations and the inorganic layer containing phosphate anions and water molecules in 4-CAH2PO4·H2O crystals are connected through a three-dimensional network of strong charge-assisted N–H···O and C-OH···O hydrogen bonds. The fingerprint plot of 4-CAH2PO4·H2O obtained indicated that the most prominent interaction corresponds to the short O···H contact, followed by the H···H and H···C contacts. The intermolecular interaction topology of 4-CAH2PO4·H2O has been quantitatively analyzed. The 4-CAH2PO4·H2O complex was optimized by density functional theory (DFT) with B3LYP/6-31G basis set and the theoretical IR vibrational spectra determined. The noncovalent interaction (NCI) and quantum theory of the atom in the molecule (QTAIM) analysis were done using Multiwfn 3.7 software. 4-CAH2PO4·H2O complex structure and its computational analysis are also compared with that of 4-carboxyanilinium dihydrogen phosphate (4-CAH2PO4).

New hydroxylammonium-based protic ionic liquids: Influence of cation and anion structure on thermal, viscosity and conductive properties

In the research work, new protic ionic liquids (Pr-ILs) were synthesized by an acid-base neutralization reaction. The influence of IL chemical structure (i.e. anion and cation nature) on the thermal behavior, viscosity and ionic conductivity was evaluated. To confirm the chemical structure of synthesized Pr-ILs, nuclear magnetic resonance (1H and 19F) and Fourier transform infrared spectroscopy analyses were performed. Thermal analysis demonstrated that the influence of anion nature on the IL thermal stability was more pronounced than that of cation. The ionic liquids with trifluoromethanesulfonate anion showed the highest thermal stability (Tdeg ∼ 410–420 °C) as compared with other studied anions (i.e. phosphate and acetate anions). The trifluoromethanesulfonate-based Pr-ILs also demonstrated high ionic conductivity – between ∼58 and ∼64 mS·cm−1 at 150 °C and non-humid conditions. Despite the fact that phosphate-based Pr-ILs were more thermally stable (Tdeg ∼ 250–280 °C) than acetate-based ones (Tdeg ∼ 215 °C), acetate-based Pr-ILs revealed a higher ionic conductivity (∼15–19 mS·cm−1 at 80 °C) than phosphate-based Pr-ILs (∼0.2–1 and ∼0.4–2 mS·cm−1 at 80 and 120 °C, respectively). The obtained results confirm that the synthesized Pr-ILs are promising candidates for using them in electrochemical applications, namely, electrodialysis and fuel cells.

Redox-gated recognition of dihydrogen phosphate using a ferrocene-tethered non-symmetric aryl-triazole pentad

ABSTRACT Anions play many roles in our environment. Consequently, the development of synthetic receptors capable of targeted anion binding is of ongoing importance. While many such receptors are known, simplified designs and measurement approaches are always beneficial. Herein, we report the synthesis of a non-symmetric aryl-triazole pentad receptor appended with a single ferrocene, its electrochemistry, and the selective binding to dihydrogen phosphate (H2PO4 –) anions of its oxidised form over various environmentally prevalent anions (HSO4 –, Cl–, NO3 –). The receptor was constructed using a modular architecture with simple installation of a ferrocene unit using click chemistry. Electrochemical analysis on the receptor revealed that addition of H2PO4 – anion led to a shift in the redox peaks of the receptor (FcP) towards more negative potentials, indicating higher anion affinity was achieved after the ferrocene was oxidised to its cationic form (FcP + ). This work verifies prior studies on the efficacy of cationic charge in simpler receptor design for the creation of functional host-guest systems.

Layered double hydroxide for slowing selenium fertilizer release and improving selenium utilization efficiency in vegetables

Selenium (Se) is a beneficial plant micronutrient, and the application of Se fertilizers can promote plant growth and enhance the Se content in crops. However, traditional soluble Se fertilizers have low utilization efficiency of Se due to adsorption or leaching. Here, selenite (SeO32−) -intercalated Mg/Al layered double hydroxide (Se-Mg/Al) for SeO32− slow-release was synthesized by co-precipitation and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Se-Mg/Al possessed a typical lamellar structure, combining with selenite by electrostatic interaction in interlayer and chemisorption on the surface. The release mechanism of selenite in distilled water from Mg/Al layered double hydroxide (Mg/Al LDH) was Fickian diffusion with gradually released 97.86% after 20 h (Over 90% within 2 h for sodium selenite). At pH range 4.0–8.0, Se-Mg/Al had a stable slow-release ability. And, the sulfate and phosphate anions could effectively trigger the release of selenite through anions exchange. The pot experiments showed that Se-Mg/Al increased Se content of vegetables, more than twice that of directly using sodium selenite. Compared with control treatment, the average stem height and fresh weight per 10 plants with Se-Mg/Al treatment improved approximately 1.48 times and 2.34 times, respectively. This work provides a feasible way for achieving crops selenium supplementation and improving selenium utilization efficiency.

Eco-friendly nanoparticles: mechanisms and capacities for efficient removal of heavy metals and phosphate from water using definitive screening design approach.

Can nano-zero-valent iron, synthesized using oak leaf extract, be the key solution for water preservation, efficiently removing heavy metal ions and phosphate anions simultaneously? This research unveils how this technology not only promises high efficiency in the remediation of water resources, but also sets new standards for environmentally friendly processes. The high antioxidant capacity and high phenol content indicate suggest the possibility of oak-nZVI synthesis using oak leaf extract as a stable material with minimal agglomeration. The simultaneous removal of Cd and phosphates, as well as and Ni and phosphates was optimized by a statistically designed experiment with a definitive screening design approach. By defining the key factors with the most significant impact, a more efficient and faster method is achieved, improving the economic sustainability of the research by minimizing the number of experiments while maximizing precision. In terms of significance, four input parameters affecting process productivity were monitored: initial metal concentration (1-9mgL-1), initial ion concentration (1-9mgL-1), pH value (2-10), and oak-nZVI dosage (2-16mL). The process optimization resulted in the highest simultaneous removal efficiency of 98.99 and 87.30% for cadmium and phosphate ions, respectively. The highest efficiency for the simultaneous removal of nickel and phosphate ions was 93.44 and 96.75%, respectively. The optimization process fits within the confidence intervals, which confirms the assumption that the selected regression model well describes the process. In the context of e of the challenges and problems of environmental protection, this work has shown considerable potential and successful application for the simultaneous removal of Cd(II) and Ni(II) in the presence of phosphates from water.

The Fluorescence Sensing Capability of 1,4-dihydroxyanthraquinone Towards Metal Ions and Imaging Cells.

Fluorescence and colorimetric sensors have gained significant traction in diverse scientific domains, including environmental, agricultural, and pharmaceutical chemistry. This article comprehensively surveys recent advancements in developing sensors employing 1,4-dihydroxyanthraquinone(1,4-DHAQ). The study delves into the unique properties of 1,4-dihydroxyanthraquinone(1,4-DHAQ) as a sensor, focusing on its capacity to detect Cu2+ ions and elucidating its fluorescence quenching mechanisms. Furthermore, the interaction of dihydroxyanthraquinone with Ga(III), Al(III), and In(III) ions is explored under both aqueous and non-aqueous conditions, leading to the formation of distinctive fluorescent species. The investigation extends to factors influencing ligand behavior, including time dependency, temperature, solvent type, counterions, and pH levels. These key parameters are systematically analyzed to understand sensor performance better. In conclusion, the article investigates the utility of the 1,4-dihydroxyanthraquinone-Zn2+ probe as a versatile sensing platform for phosphate anions, particularly in live cell imaging. The findings contribute to the evolving landscape of sensor technologies, offering insights into the diverse applications and potential advancements in this burgeoning field.

Rhombohedral platinum-copper intermetallic compound: A high phosphate tolerance electrocatalyst for HT-PEMFC

In high-temperature proton exchange membrane fuel cells (HT-PEMFC), phosphate anions act as a poisonous 'spectator species', binding strongly to the Pt surface through PtO bonds similarly to O2. This blocks the Pt active sites, resulting in slow ORR kinetics. Herein, we synthesized ultrafine L11-PtCu intermetallic compound nanoparticles (O-PtCu/S-C) loaded on an S-doped carbon support with an average size of about 3 nm through wet impregnation followed by hydrogen annealing, which showed high resistance to phosphate poisoning. The introduction of S notably improved the metal-support interaction and prevented particle growth during annealing, which is beneficial for the uniform distribution of nanoparticles and prevents detachment and agglomeration during ADT. The pronounced Cu-Pt electronic interaction in O-PtCu/S-C induced electron transfer from Cu to Pt, which effectively modified the electronic structure of Pt and weakened the adsorption energy of phosphate anions on the catalyst surface. In addition, the phosphate poisoning test results from both room temperature RDE and high-temperature RDE demonstrate that O-PtCu/S-C possesses excellent phosphate tolerance, superior ORR activity, and remarkable stability. It exhibits a superior peak power density of 800.5 mW cm−2 in 160°C H2-O2 HT-PEMFC with Pt loading of 0.5 mg cm−2. This research offers a novel approach to designing phosphate-resistant electrocatalysts for HT-PEMFC.

Modulating fluorescent sensing of the pyrene-based ion pair receptor by docking on graphene quantum dots

We successfully synthesized squaramide-based ion pair receptor 3, possessing a cation binding domain linked to the receptor scaffold so as act as an electron-withdrawing group and enhance anion binding. This compound was able to efficiently and cooperatively bind anions in the presence of sodium cations. Using reference compounds 1 and 2, we demonstrated that the presence of a carbonyl group on the aromatic ring significantly enhances the efficiency of anion binding. The incorporation of this group in the structure of receptor 3, combined with other strongly electron-withdrawing groups located on another aryl subunit, enabled the receptor to bind salts even in the presence of water. Furthermore, the capacity for modular synthesis of diarylsquaramides allowed to obtain sensor 4, which features a pyrene moiety directly attached to the anion-binding domain, selectively sensing dihydrogen phosphate anions. Besides the signaling feature, the presence of pyrene rings facilitated the docking of sensor 4 onto the surface of graphene quantum dots, resulting in a conjugate with improved fluorescent properties.

Sequence closed-loop recovery of fluoride, phosphate, and sulfate anions from phosphogypsum leachate via precipitation-electrodialysis-crystallization approaches

Phosphogypsum (PG) is a large-scale industrial by-product generated during the production of phosphoric acid, typically being deposited in landfills worldwide. The leaching of fluoride (F−), phosphate (PO43−), and sulfate (SO42−) anions from PG into water bodies through rainfall results in significant environmental pollution. Herein, we propose a stepwise precipitation combined with electrodialysis and crystallization strategy for efficient recovery and valorization of multiple anions from PG leachate. Our method demonstrates effectiveness both theoretically and practically. Consequently, fluoride anions were precipitated as CaF2 and Ca5(PO4)3F at pH 4.7, with a recovery rate of 98.80 %; phosphate anions as MgNH4PO4·H2O at pH 8.5, with a recovery rate of 99.91 %; and sulfate anions through electrodialysis and crystallization with a recovery efficiency of 99.89 %, ensuring effluent met discharge standards. In addition, the concentrated sulfate-rich solution was employed for electrochemical production of persulfate, yielding ammonium persulfate salts after cooling crystallization. Our integrated approach for multiple anion recovery from PG leachate offers significant environmental and economic benefits, providing valuable insights and references for future research and practical production.

Effect of Formation Temperature of Zirconium Dioxide on its Phase Composition and the Efficiency of Adsorptive Removal of Phosphate Anions from a Water Solution

Effect of Formation Temperature of Zirconium Dioxide on its Phase Composition and the Efficiency of Adsorptive Removal of Phosphate Anions from a Water Solution

Synthesis, Spectroscopic Evaluations and UV-Vis Titration Studies of New Symmetrical Amide Compounds Derived from N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic Acid Methyl Ester

In this study, 2 flexible and pre-organized tetraamide compounds derived from N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic acid methyl ester namely 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]pentane (L1) and 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]hexane (L2) have been successfully synthesized when reacted with diamines in 1:2 ratio. These new compounds were built from combination of 3 main components, as a trend requires for anion receptor which are (i) 2,6-pyridine dicarboxamide moieties as targeted anion binding host, (ii) amino methyl pyridine pendants arms as the flexible moieties and (iii) pentyl (-C5H10-) and hexyl (-C6H12-) unit as the spacer. Compounds L1-L2 were fully characterized by using elemental analyzer, Fourier transform infrared (FTIR) spectroscopy, gas chromatography-mass spectroscopy (GC-MS), 1H, 2D NOESY and 13C Nuclear Magnetic Resonance (NMR) spectroscopies, and Ultraviolet-visible (UV-Vis) spectroscopies. In this study, anion titration methods were used to identify the affinity towards selected anions. The results showed that L1 (having a pentyl spacer) had the highest affinity towards phosphate anions as compared to L2, where the red shift changes were observed in the UV-vis spectrum at the amide region. HIGHLIGHTS Two novel amide compounds with flexible and pre-organized structure are designed for use as potential anion receptors The flexible moieties at the amide and the linker allow hydrogen bonding interaction of the molecules with variety anions with different geometries Anion titration studies revealed good affinities towards phosphate anions as suggested in Hofmeister trend GRAPHICAL ABSTRACT

Reduction-orientated selective removal of selenate by thiourea-functionalized polystyrene material

Efficient removal of trace selenate [Se(VI)] from contaminated water is still challenging because of the inevitable interference from the coexisting anions toward the adsorption or ion-exchange process. Herein, a bifunctional material (NCS@CMPS) was proposed for selective removal of Se(VI) from a complex matrix. NCS@CMPS was subtly prepared by grafting a chloromethylated polystyrene substrate (CMPS) with thiourea, resulting in reductive groups (C-SH and C=S) and adsorptive sites (–NH-, –NH2, and C=NH2+) anchored on the skeleton of CMPS. Batch studies demonstrated an excellent removal efficiency and anti-interference capabilities of NCS@CMPS toward Se(VI), even with very high levels of competing anions (chloride, sulfate, phosphate, nitrate, and bicarbonate) over a wide pH range (3 ∼11). The in-situ reductive removal and the unique pH-buffering effect of NCS@CMPS were responsible for the high selectivity and the wide applicability. The XPS analyses identified the removal mechanisms of concentrating, reducing, and sequestrating of Se species inside NCS@CMPS, where the majority of Se species was reduced to Se(IV) (80.9%). In column mode, NCS@CMPS can treat over 10,000 bed volumes (BV) of a simulated Se(VI) wastewater ([Se]ini = 200 μg/L) to below 10 μg/L, whereas the capacity of its substrate (i.e., CMPS) was only 28 BV. Additionally, the exhausted NCS@CMPS can be regenerated by NaBH4-NaOH-HCl treatment for repeated use. Moreover, the effectiveness of NCS@CMPS in treating actual industrial Se(VI) wastewater was also validated.

Synthesis and characterization of surface-modified magnetic mesoporous silicate materials for phosphate adsorption.

The magnetic mesoporous silica material, Mag-MCM-41, was synthesized by coating magnetite (Fe3O4) nanoparticles with a mesoporous material called MCM-41. Mag-MCM-41 and modified nanomaterials Mag-MCM-41-NN and Mag-MCM-41-NN-Fe+3 which were modified with aminopropyl functional groups. In water and wastewater, phosphate anions are considered significant contaminants due to their detrimental impact on the environment. They promote the growth of algae, leading to eutrophication. The purpose of this study is to investigate the removal of phosphate anions from aqueous solutions using modified magnetic silica particles. The Mag-MCM-41 material exhibits hexagonal properties and belongs to the class of "mesoporous" materials. It has a surface area of 923 m2.g-1, which was determined through N2 adsorption-desorption isotherms, FTIR, TEM, BET, and SAXS analysis. Kinetic and adsorption isotherm studies were conducted using Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents to examine the behavior of phosphate anions. The kinetic and adsorption isotherm studies of phosphate anions revealed that the adsorption process on Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents followed the chemical adsorption mechanism. Phosphate adsorption on all adsorbents occurred in a monolayer, and the MCM-41-NN-Fe+3 adsorbent exhibited the highest maximum adsorption capacity (qm) value of 112.87 mg.g-1 compared to the other adsorbents.

Ca2+ efflux facilitated by co-transport of phosphate anion in H+/Ca2+ antiporter

Ca2+ efflux facilitated by co-transport of phosphate anion in H+/Ca2+ antiporter

Dynamic and Reversible Blending Interface on Polyoxovanadate Electrode for High-Performance Lithium-Ion Batteries.

Solid electrolyte interphase (SEI) plays a critical role in the performance of lithium-ion batteries (LIBs). In contrast to the clear interface between the traditional consecutive electrode materials and SEI, ionic polyoxometalates (POMs) as electrode could bilaterally diffuse with SEI and form a blending interface for superior electrochemical performance. POMs have recently aroused much interest as electrode materials in LIBs due to their structural flexibility, high capacity, and cycling stability. However, the interface evolution between POM-based electrodes and SEI, which is critical for Li+ ion transportation, has rarely been explored. Herein, we choose Li10[V12B18O60H6] (LVB) as an example to investigate the formation and structural evolution of the electrode-electrolyte interface. Time-of-flight secondary ion mass spectrometry together with X-ray photoelectron spectroscopy demonstrates the evolution of a blending layer at the interface containing typical SEI components, a polyanion from LVB and a phosphate anion from decomposition products of LiPF6. In the blending layer, ion migration takes place between the P-related inorganic species and the polyanion during the Li+ insertion/extraction reaction. Such a compatible blending layer favors Li+ transportation and the reversibility of the redox reactions, as supported by a series of electrochemical analyses. This work provides detailed insights into understanding the interface evolution of the LVB electrode and demonstrates the importance of interfacial engineering to induce proper interface layers in the development of high-performance POM-based electrodes for LIBs.

Water-Soluble Triazolium Covalent Cages for ATP Sensing.

Water-soluble organic cages are attractive targets for their molecular recognition and sensing features of biologically relevant molecules. Here, we have successfully designed and synthesized a pair of water-soluble cationic cages employing click reaction as the fundamental step followed by the N-methylation of the triazole rings. The rigid and shape-persistent 3D hydrophobic cavity, positively charged surface, H-bonding triazolium rings, and excellent water solubility empower both cages to exhibit a superior affinity and selectivity for binding with adenosine-5'-triphosphate (ATP) compared to cyclophanes and other macrocyclic receptors. Both cage molecules (PCC⋅Cl and BCC⋅Cl) can bind a highly emissive dye HPTS (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt) to form non-fluorescent complexes. The addition of ATP resulted in the stronger cage⊂ATP complexes with the retention of HPTS emission upon its displacement. The resultant indicator-displacement assay system can efficiently sense and quantify ATP in nanomolar detection limits in buffer solutions and human serum matrix. Spectroscopic and theoretical studies revealed the synergistic effect of π⋅⋅⋅π stacking interaction between the aromatic moiety of the cationic cages and the adenine moiety of ATP, as well as the electrostatic and hydrogen bonding interaction between the phosphate anion of ATP and triazole protons of cages, played the pivotal roles in the sensing process.