Anion Exchange Research Articles

Effects of DOM and cations on the diffusion migration of PPCPs through ion exchange membranes

The transportation of pharmaceuticals and personal care products (PPCPs) in ion-exchange membranes was worrying, especially in complex substrates. Dissolved organic matter (DOM), the complexation of PPCPs and the membrane pollution formed by DOM were often confused in the existing studies. This paper investigated the diffusive migration patterns of three kinds of (PPCPs) through ion exchange membranes (IEMs) in complex substrates. Triclosan (TCS) exhibited the most probability of migration. Without considering the interference of environmental factors, more than 90 % of TCS was adsorbed by IEMs. The migration of sulfadiazine sodium (SD) and carbamazepine (CBZ) was less than 5 %. The DOM and cations altered the interaction of PPCPs and IEMs. DOM fouling on IEMs converted the direct strong binding of TCS to IEMs to indirect weak binding, and increased the transmembrane migration of TCS consequently. The presence of cations (Ca2+ and Mg2+) increased the inorganic binding of TCS to IEMs, and also promoted the transmembrane migration of TCS. However, coexisting of Mg2+ and humic acid (HA) decreased TCS migration through anion exchange membrane (AM), but increased TCS migration through cation exchange membrane (CM) due to the increasing of solution potential. The research provided a theoretical basis for exploring the safety of product solutions in IEMs systems.

Highly selective separation of 99TcO4−/ReO4− with rapid liquid-liquid two-phase disengagement by amine-diamide ligands

Efficient and selective extraction of pertechnetate (TcO4−) from nitric acid medium has become a significant challenge, especially in the presence of a large excess of interfering anions. By employing a combined strategy involving H-bonding and electrostatic interaction, a highly selective extraction of TcO4− can be achieved. The present work reports three homologous amine-diamide ligands with different alkyl chain lengths on the amine N atom of 2,2′‐(metylimino)bis(N,N‐dioctylacetamide) (MIDOA), 2,2′‐(butylimino)bis(N,N‐dioctylacetamide) (BIDOA) and 2,2′‐(octylimino)bis(N,N‐dioctylacetamide) (OIDOA), and their extraction behaviors for TcO4−/ReO4− in HNO3 solution are also investigated by using n-dodecane as a diluent. It has been shown that all of them exhibit excellent extractability and high selectivity to TcO4−/ReO4−. Their extractability and phase disengagement follow the order of OIDOA > BIDOA > MIDOA, revealing a greater extractability and rapider phase disengagement for the amine-diamide ligand with longer chain substituents on the amine N atom. Both slope analysis and loading capacity test indicate the formation of 1:1 metal/ligand extracted complex, which is also confirmed by the analyses of single-crystal X-ray diffraction (SC-XRD), electrospray ionization mass (ESI-MS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). The extraction of TcO4−/ReO4− by the amine-diamide ligand follows the anion exchange extraction model and is a spontaneous and endothermic process. Furthermore, a competing extraction test was also conducted and demonstrates excellent extractability and high selectivity to TcO4−/ReO4−.

Leaching-readsorption of VO43− optimized diffusion and adsorption of OH− on NiFeOOH catalytic interface for industrial water oxidation

The robustness of NiFe-based oxygen evolution reaction (OER) electrocatalysts is a bottleneck in alkaline industrial water cracking. Herein, the effects of trace Fe doping and leaching-readsorption of VO43− on the activity and stability of activated nickel-vanadium oxide (NVO) were investigated. As a result, the controlled leaching of VO43− created sufficient oxygen vacancies (Ov) for surface reconstruction to NiFeOOH, while its moderate readsorption promoted the diffusion of OH−. The modulated NVO (aFe-NVO) has an overpotential of only 340 mV at 1000 mA cm−2 and can operate stably for 100 h. Density functional theory calculations (DFT) show that the synergistic interaction between sufficient OV, Fe doping and the leaching-readsorption of VO43− optimizes the adsorption of OH−, and significantly reduces the energy barrier of rate-determining step (RDS) (*OH → *O). Furthermore, the assembly of aFe-NVO in alkaline anion exchange membrane (AEM) cells resulted in a cell voltage of 1.95 V at 1000 mA cm−2 and stable operation for 100 h.

4-Halomethyl-Substituted Imidazolium Salts: A Versatile Platform for the Synthesis of Functionalized NHC Precursors.

N,N'-Diarylimidazolium salts containing haloalkyl functional groups that are reactive with various nucleophiles are considered to be promising reagents for the preparation of functionalized N-heterocyclic carbene (NHC) ligands, which are in demand in catalysis, materials science, and biomedical research. Recently, 4-chloromethyl-functionalized N,N'-diarylimidazolium salts became readily available via the condensation of N,N'-diaryl-2-methyl-1,4-diaza-1,3-butadienes with ethyl orthoformate and Me3SiCl, but these compounds were found to have insufficient reactivity in reactions with many nucleophiles. These chloromethyl salts were studied as precursors in the synthesis of bromo- and iodomethyl-functionalized imidazolium salts by halide anion exchange. The 4-ICH2-functionalized products were found to be unstable, whereas a series of novel 4-bromomethyl functionalized N,N'-diarylimidazolium salts were obtained in good yields. These bromomethyl-functionalized imidazolium salts were found to be significantly more reactive towards various N, O and S nucleophiles than the chloromethyl counterparts and enabled the preparation of previously inaccessible heteroatom-functionalized imidazolium salts, some of which were successfully used as NHC proligands in the preparation of Pd/NHC and Au/NHC complexes.

Origin of Enhanced Oxygen Evolution in Restructured Metal–Organic Frameworks for Anion Exchange Membrane Water Electrolysis

AbstractMetal–Organic Frameworks (MOFs), praised for structural flexibility and tunability, are prominent catalyst prototypes for exploring oxygen evolution reaction (OER). Yet, their intricate transformations under OER, especially in industrial high‐current environments, pose significant challenges in accurately elucidating their structure–activity correlation. Here, we harnessed an electrooxidation process for controllable MOF reconstruction, discovering that Fe doping expedites Ni(Fe) MOF structural evolution, accompanied by the elongation of Ni−O bonds, monitored by in situ Raman and UV/Visible spectroscopy. Theoretical modeling further reveals that Fe doping and defect‐induced tensile strain in the NiO6 octahedra augments the metal ds‐O p hybridization, optimizing their adsorption behavior and augmenting OER activity. The reconstructed Ni(Fe) MOF, serving as the anode in anion exchange membrane water electrolysis, achieves a noteworthy current density of 3300 mA cm−2 at 2.2 V while maintaining equally stable operation 500 mA cm−2 for 300 h and 1000 mA cm−2 for 170 h. This undertaking elevates our comprehension of OER catalyst reconstruction, furnishing promising avenues for designing highly efficacious catalysts across electrochemical platforms.

Ultralong Compositional Gradient Perovskite Nanowires Fabricated by Source-Limiting Anion Exchange.

Anion exchange in halide perovskites offers prospective approaches to band gap engineering for miniaturized and integrated optoelectronic devices. However, the band engineering at the nanoscale is uncontrollable due to the rapid and random exchange nature in the liquid or gas phase. Here, we report a source-limiting mechanism in solid-state anion exchange between low-dimensional perovskites, which readily gives access to ultralong compositional gradient nanowires (NWs) with lengths of up to 100 μm. The exchanged NWs remain single-crystalline with intact morphology, while the halogen content exhibits an apparent gradient distribution, leading to a tapered energy band profile along a NW. In the dynamic study of anion behavior, it is shown that the spatial stoichiometric composition can be precisely tuned following Fick's law of diffusion. In addition, self-powered, spectrally resolved photodetectors incorporating multiple detection units within a single gradient NW are demonstrated. This work provides a feasible strategy for the realization of perovskite-based ultracompact optoelectronics, imaging sensors, and other miniaturized semiconductor devices.

CoAl-LDH on ZIF-67 template inserted into the conductive matrix as a high-efficiency composite anode for facilitating phosphorus elimination

Phosphorus pollution can induce water eutrophication and critically threaten the stability of the aquatic ecosystem. Capacitive deionization (CDI) is a potential candidate for controlling phosphorus levels due to its lack of chemical requirements, eco-friendliness, and low energy demand. Herein, a novel ZIF-67-derived CoAl-LDH embedded in conductive carbon skeletons (CoAl-LDH/C) was successfully constructed by a self-sacrificial template strategy. A conductive carbon matrix is incorporated into LDH, which can alleviate the insufficient conductivity and aggregation issues for LDH. The results revealed that CoAl-LDH/C possesses superior phosphorus elimination properties (qm=32.7 mg P/g) at 1.2 V, benefiting from its abundant active sites, large mesoporous diameter, specific surface area, total pore volume, outstanding specific capacitance, and ion diffusion. Meanwhile, the energy consumption of CoAl-LDH/C is merely 3.398 kWh/kg and 0.024 kWh/m3. CoAl-LDH/C also proved flexible for practical applications regarding complex water quality (wide pH range, coexisting substances, natural water) and cyclic utilization. Finally, the potential mechanism illuminated that the phosphorus elimination process in an electric field engages with ligand exchange, anion exchange, electrostatic attraction, and hydrogen bonds. This work paves a promising concept for designing innovative LDH-based electrodes with excellent ion diffusion and superior conductivity to eliminate phosphorus efficiently.

Laccase purification and azo dye decolorization potential of Sparassis latifolia

Sparassis latifolia often referred to as Cauliflower mushroom possess both medicinal and edibility values. In this research work, first time laccase purification and dye colourisation efficacy of Sparassis latifolia’s purified laccase were assessed. Optimal laccase potential was noted after 12th day of incubation with 4 pH of medium at 45 °C. As supplementary nutritional source, sucrose and ammonium sulphate were unveiled as most effective synthetic carbon and nitrogen sources while wheat straw found as proficient lignocellulosic biomass for enhanced laccase production. Following optimisation of laccase production parameters, laccase was purified to 14.2 fold by ammonium sulphate precipitation, dialysis and anion exchange chromatography. Laccase molecular weight determined through SDS PAGE was found to be of 65 KDa. This purified laccase was tested for its ability to decolourise the Congo red at definite pH and temperature. It was found that this fungus has capability to decolourise up to 98.6% of Congo-red dye.

Study on the Adsorption Mechanism of Cu2+ by ZnAl-LDH-Containing Exchangeable Interlayer Chloride Ions.

Different Zn/Al ratios of Cl- intercalated ZnAl-layered double hydroxide (ZnAl-LDH) were prepared using the coprecipitation method, and their adsorption performance for Cu2+ in aqueous solution was evaluated. The factors affecting adsorption properties, such as dosage, reaction time, and pH, were determined by adsorption experiments. Then, the adsorption kinetics and isotherm models were fitted to evaluate the adsorption mechanism. The results show that the Zn/Al ratio has a great influence on the adsorption effect, the best adsorption effect is obtained when the Zn/Al ratio is 4:1, and the maximum adsorption capacity of Cu2+ is 213 mg/g. The mechanism study shows that the adsorption of Cu2+ by ZnAl-LDH is mainly an isomorphic substitution. Additionally, during the adsorption of CuSO4, the presence of SO42- undergoes interlayer anion exchange with Cl-, and the process of SO42- entering the interlayer facilitates the isomorphic substitution of Cu2+ and Zn2+. X-ray diffraction (XRD) analysis shows that as the Zn/Al ratio increases, the interlayer spacing of ZnAl-LDH increases, and the crystallinity decreases. The adsorption process conforms to the pseudo-second-order kinetic process and the Langmuir isotherm adsorption model. Therefore, the adsorption type of ZnAl-LDH for Cu2+ is monolayer chemical adsorption. The adsorption thermodynamic results indicate that the adsorption of Cu2+ is a spontaneous endothermic process. The research results revealed the mechanism of ZnAl-LDH adsorbing Cu2+, providing ideas for removing and recovering copper-containing electroplating wastewater.

Optimization, structural characterization, and biological applications of exopolysaccharide produced by Enterococcus faecium KT990028

The aim of this study was to select the best exopolysaccharide (EPS) producer among the Enterococcus strains to optimize, characterize, and evaluate its biological properties. Among the eleven strains, Enterococcus faecium KT990028 was selected, and the production conditions were optimized: 16.3 % (w/v) sucrose, 0.70 % (w/v) yeast extract, 8.3 % (w/v) reconstituted skimmed milk, at 38 °C in 15 h of incubation, producing 2.880 g/L of EPS. High performance anion exchange chromatography (HPAEC) analysis revealed that the molecular weight was 166.98 kDa. HPAEC, spectroscopy (FTIR), and nuclear magnetic resonance (1H NMR) analyses revealed that the EPS was a heteropolysaccharide composed of galactose (37.74 %), rhamnose (19.79 %), arabinose (17.71 %), glucose (9.50 %), fucose (7.93 %), and mannose (7.33 %). Scanning electron microscopy showed a three-dimensional microstructure in the form of decompressed plates, with wrinkles, and pores. By means of dynamic light scattering (DLS), the EPS showed an average size varying from 135.25 ± 10.56 nm and 410.60 ± 45.20 nm, as the concentration was increased from 0.5 mg/mL to 2.0 mg/mL, respectively. X-ray diffraction revealed that the EPS has an amorphous and crystalline nature, while thermogravimetric analysis indicated stability up to 400 °C. The antioxidant effect (5 mg/mL) against DPPH, ABTS, OH, and O2 was 64.50 ± 0.71 %, 47.50 ± 0.10 %, 68.36 ± 0.59 %, and 44.83 ± 0.86 %, respectively. It was also able to inhibit and biofilm disruption of Escherichia coli ATCC 25922 and Enterococcus faecalis ATCC 6057 and had an antimicrobial effect from 50 mg/mL for the strains of against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes ATCC 19117, Staphylococcus aureus ATCC 6538, and Enterococcus faecalis ATCC 6057. Cell cytotoxicity carried out using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that the EPS was safe and promoted the proliferation of Vero cells. Thus, the results indicated that the EPS from E. faecium KT990028 is a promising functional biopolymer for possible applications in the food and pharmaceutical fields.

Rapid and Effective Determination of Ethyl Glucuronide in Hair by Micro Extraction by Packed Sorbent (MEPS) and LC-MS/MS.

Ethyl glucuronide (EtG) in hair is a reliable biomarker of alcohol consumption habits. Due to its small concentration incorporated into hair, analytical methods sensitive enough to reliably quantify EtG in this matrix are required. Sample preparation is critical in hair analysis, especially for EtG, for which extraction efficiency and matrix effect can strongly influence the results; furthermore, miniaturized methods are sought, to reduce solvent use and times of sample preparation. A micro extraction by packed sorbent (MEPS) procedure coupled to a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of EtG in human hair samples. Fifty milligrams of hair samples were cut into snippets and extracted in water. The cleanup of the extract was carried out by using a MEPS syringe packed with anion exchange sorbent (SAX); all parameters for conditioning, washing, loading and eluting steps were optimized and the eluted aqueous volume was directly injected in the LC-MS/MS system operating in the negative ionization mode. The method was fully validated assessing LOD, LOQ, calibration curve, repeatability, accuracy, matrix effect and carryover. The method was subsequently applied to QCs and authentic hair samples. The developed MEPS method is quick and effective, with low solvent purchase and discard costs, allowing the differentiation between social drinkers and chronic excessive alcohol consumers, according to the cut-offs established by the Society of Hair Testing (SoHT).

The influence of CuxS particles on the thermal decomposition of anion exchangers

AbstractDue to the versality, surface imperfections and diverse redox chemistry of CuxS, hybrid ion exchangers (HIXs) containing these particles are an interesting object of research, including thermal transformation. The composite materials used for testing were strongly basic anion exchangers, with macroreticular (M) and gel-type structure (G), containing in the poly (styrene/divinylbenzene) skeleton fine particles of covellite/brochantite (M1), covellite (M2), covellite/digenite/djurleite (G1) and covellite/digenite (G2). The prepared HIXs contained 12–16 mass% S + Cu. They were subjected to thermal analysis under air and N2 to identify the role of the inorganic phase in decomposition of the polymeric phase. The results were discussed on the basis of the TG/DTG curves and X-ray diffraction (XRD) patterns of the solid residues (CuO after combustion, carbon/Cu2S after pyrolysis). It was found that CuxS in the resin phase exhibited oxidative activity promoting the combustion process. The polymeric skeleton of HIXs decomposed in air at a much lower temperature compared to pure resins (400 vs 600 °C). The TG/DTG curves had a model shape, three separate conversions occurring in a narrow temperature range, which indicated sequential decomposition. The low consumption of hydrogen for the reduction of CuxS to Cu2S during pyrolysis was not conducive to condensation of alkyl radicals and increase of the mass of carbon matter. The results advance the understanding of the effect of copper/sulfur-containing fine particles on the thermal decomposition of anion exchanger and can be useful in preparation of multifunctional carbon-containing composite materials.

SLC4A3 anion exchanger mutations associated to sudden death : short or long QT syndrome?

Abstract Introduction SLC4A3 gene codes for an (Cl-/HCO3-) exchanger present on the surface of cardiomyocytes (AE3 channel) is involved in maintaining the physiological acid-base gradient of the cardiomyocyte at rest. Loss of function of the SLC4A3 gene leading to an increase in intracellular pH has. been reported to be responsible for short QT syndrome (SQT). Methods The aim of our study was to characterize the genotype-phenotype relationships of SLC4A3 mutations identified in the French databases (Paris, Nantes and Lyon) in patients with sudden death. Through systematic exome sequencing we identified 3 new SLC4A3 variants in 3 families with a history of sudden death in two universitary hospitals. Results Family 1. The c.3209G>C variant (p.Gly1070Ala) in the SLC4A3 gene was identified in a 7-yo boy with VF at sleep but admitted in encephalic death. EKG showed short QT (QTc 280ms). Clinical examination, blood tests, TTE and autopsy were normal. There was no family history of sudden death. His mother had EKG evidence of SQT and was carrier the SLC4A3 mutation. She was implanted with an ICD. His two older brothers and the rest of the family had no mutation or pathological ECG and were asymptomatic. Family 2. The c.1027C>T (p.Arg343Cys) mutation in the SLC4A3 gene was identified in a 29-year-old man who presented with sudden death at sleep (VF). Clinical examination, blood tests, TTE and autopsy were normal. A maternal uncle died suddenly while sleeping. His two brothers (30 and 27 yo) are both carriers of the SLC4A3 mutation and exhibit SQT (QTc 320 and 330 ms respectively). TEE, Holter monitoring and stress test were normal in both. Both brothers were treated with hydroquinidine. Over a 2-year follow-up they had no symptom nor AF. Family 3. The c.1022C>G (p.Thr341Arg) mutation was identified in the SLC4A3 gene in a 54-yoman who presented with VF during shower but admitted in encephalic death. There was no family history of sudden death. Clinical examination, blood tests and echocardiography as well as coronary angiogram were normal. The initial ECG showed a prolonged QT interval (QTc 520 ms). QTc decreased to 480 ms in the 48 following hours. His parents and his sister as well as his 18 yo daughter have normal QTc values. We are awaiting the genetic results. Conclusion Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 has been recently reported to cause short QT syndrome but it seems that in rare cases it may also be responsible for LQTS. Further patients are needed to confirm these data. In order to understand the underlying electrophysiological mechanisms, we plan to characterize the cellular impact of these new mutations through IPS.

Characterization of knock-in zebrafish models with a novel SLC4A3 variant identified in a short QT syndrome family

Abstract Background Short QT syndrome (SQTS) is one of the lethal inherited arrhythmia syndromes leading to ventricular fibrillation (VF) and cardiac death. It is mainly caused by pathogenic variants in ion channel related genes, especially KCNH2 which produces IKr. Recently, SLC4A3 encoding a membrane-localized anion exchanger 3 (AE3) that regulates intracellular pH (pHi), has been reported as a causative gene for SQTS. However, the molecular mechanism of SLC4A3 variants which cause SQTS remains unclear. Purpose Functional characterization of a novel SLC4A3 variant identified in a SQTS family. Methods We performed target gene and whole exome sequencing to detect pathogenic variants in a family with SQTS. Patch-clamp analyses were performed to determine the electrophysiological properties using HEK293 cells. We constructed stable cell lines expressing wild-type (WT) or the SLC4A3 variant based on HEK293 cells. To evaluate the intracellular pH (pHi) level, we measured pHi using BCECF-AM via time-lapse microscopy. To clarify the pathogenesis of the SLC4A3 variant in vivo, we injected CRISPR-Cas9 and a repair template into one-cell stage zebrafish embryos and established a SLC4A3 knock-in (KI) zebrafish model (hereafter referred to as slc4a3 zebrafish). Action potential durations (APD) were recorded in slc4a3 zebrafish at 3 days post-fertilization (dpf). Results We identified two novel variants in KCNH2 (c.280 c>t, p.H70Y) and SLC4A3 (c.1059 c>a, p.N353K) in a SQTS patient. Both variants were co-segregated in the patient’s family with short QT intervals (Figure A). By electrophysiological analysis, KCNH2-H70Y did not increase IKr. We over-expressed KCNH2 (WT and H70Y), KCNQ1, and KCNJ2 in the SLC4A3 stable cell lines (WT and N353K) though no increase of IKr, IKs, and IK1 was observed. In the analysis of pHi, cells expressing SLC4A3-N353K showed significantly slower pHi alternations than those with WT, indicating the loss-of-function effect of transport kinetics in the regulation of pHi. In the electrophysiological analysis of the slc4a3 zebrafish, which harbors the paralogous variant of SLC4A3-N353K, APD20, 50, and 70 were significantly shortened in the slc4a3 KI zebrafish (HOMO) compared to the control (WT), providing evidence for the shortened QT interval with the SLC4A3 variant in vivo (Figure B). Furthermore, slc4a3 zebrafish developed severe cardiac edema (HET and HOMO: Figure C, arrows) with no gross morphological defects in other organs, which may indicate the specific role of SLC4A3-N353K in cardiac function. Conclusion We identified a novel SLC4A3 variant, p.N353K, in a family with SQTS and revealed its contributions to the pHi control and the shortened APD. Further analysis will be necessary to clarify the mechanism by which SLC4A3-N353K causes QT shortening.

All‐Optical Imaging Using Perovskite Nanocrystals Based on Spectro‐Spatial Correlation

AbstractThe exponential growth of data from sensors and internet‐connected devices has challenged traditional electronic computing, particularly in processing speed and power efficiency. Optical information processing, with its inherent high speed and parallelism, offers a promising solution. Moreover, optical processing is vital for developing all‐optical networks, where all‐optical imaging is essential. In this paper, a novel all‐optical imaging technique that leverages in situ anion exchange reactions between perovskite nanocrystals to create an array of pixels with tunable emission wavelengths is proposed. This method enables the conversion of UV light, whether transmitted or reflected by an object, into the visible spectrum, thereby establishing a direct correlation between spectral and spatial information. By employing wavelength division multiplexing (WDM), the approach reduces the dimensionality of information acquisition from two dimensions to one, enhancing imaging speed. This innovation paves the way for significant advancements in all‐optical imaging and image processing, offering new possibilities for faster and more efficient imaging technologies.

Inorganic–organic hybrid nonwoven fabrics with colorimetric detection capability for borate ions in aqueous solutions

Abstract A nonwoven fabric sheet with an immobilized colorimetric reagent was prepared to detect borate anions in aqueous media. The fabric comprised immobilized chromotropate and 1-butanesulfonate anions and chromotropate, as the colorimetric reagent, per anion exchange capacity of the layered double hydroxide. The resulting sheet quantitatively detected borate anions through photoluminescence measurements. Thus, it can be used for onsite quantitative analysis of dissolved boron in water, with promising potential for water quality monitoring and, consequently, sustainable and safe water resources globally.

Engineering Lattice Oxygen Regeneration of NiFe Layered Double Hydroxide Enhances Oxygen Evolution Catalysis Durability.

The lattice oxygen mechanism (LOM) endows NiFe layered double hydroxide (NiFe-LDH) with superior oxygen evolution reaction (OER) activity, yet the frequent evolution and sluggish regeneration of lattice oxygen intensify the dissolution of active species. Herein, we overcome this challenge by constructing the NiFe hydroxide/Ni4Mo alloy (NiFe-LDH/Ni4Mo) heterojunction electrocatalyst, featuring the Ni4Mo alloy as the oxygen pump to provide oxygenous intermediates and electrons for NiFe-LDH. The released lattice oxygen can be timely offset by the oxygenous species during the LOM process, balancing the regeneration of lattice oxygen and assuring the enhancement of the durability. In consequence, the durability of NiFe-LDH is significantly enhanced after the modification of Ni4Mo with an impressively durability for over 60 h, much longer than that of NiFe-LDH counterpart with only 10 h. In-situ spectra and first-principle simulations reveal that the adsorption of OH- is significantly strengthened owing to the introduction of Ni4Mo, ensuring the rapid regeneration of lattice oxygen. Moreover, NiFe-LDH/Ni4Mo-based anion exchange membrane water electrolyzer (AEMWE) presents an impressive durability for over 150 h at 100 mA cm-2. The oxygen pump strategy opens opportunities to balance the evolution and regeneration of lattice oxygen, enhancing the durability of efficient OER catalysts.

Engineering Lattice Oxygen Regeneration of NiFe Layered Double Hydroxide Enhances Oxygen Evolution Catalysis Durability

The lattice oxygen mechanism (LOM) endows NiFe layered double hydroxide (NiFe‐LDH) with superior oxygen evolution reaction (OER) activity, yet the frequent evolution and sluggish regeneration of lattice oxygen intensify the dissolution of active species. Herein, we overcome this challenge by constructing the NiFe hydroxide/Ni4Mo alloy (NiFe‐LDH/Ni4Mo) heterojunction electrocatalyst, featuring the Ni4Mo alloy as the oxygen pump to provide oxygenous intermediates and electrons for NiFe‐LDH. The released lattice oxygen can be timely offset by the oxygenous species during the LOM process, balancing the regeneration of lattice oxygen and assuring the enhancement of the durability. In consequence, the durability of NiFe‐LDH is significantly enhanced after the modification of Ni4Mo with an impressively durability for over 60 h, much longer than that of NiFe‐LDH counterpart with only 10 h. In‐situ spectra and first‐principle simulations reveal that the adsorption of OH− is significantly strengthened owing to the introduction of Ni4Mo, ensuring the rapid regeneration of lattice oxygen. Moreover, NiFe‐LDH/Ni4Mo‐based anion exchange membrane water electrolyzer (AEMWE) presents an impressive durability for over 150 h at 100 mA cm−2. The oxygen pump strategy opens opportunities to balance the evolution and regeneration of lattice oxygen, enhancing the durability of efficient OER catalysts.

Air and Water Stable Bicyclic (Alkyl)(Amino)Carbene Stabilized Phosphenium Cation: Reactivity and Selective Fluoride Ion Affinity.

The synthesis and reactivity of an air and water stable Bicyclic (alkyl)(amino)carbene (BICAAC) stabilized phosphenium cation (1) is reported. Air and water stable phosphenium cation are rare in the literature. Compound 1 is obtained by reaction of BICAAC with Ph2PCl in THF followed by anion exchange with LiOTf. The reduction and oxidation of 1 yielded corresponding α-radical phosphine species (2) and BICAAC stabilized phosphenium oxide (3) respectively. All compounds are well characterized by single crystal X-ray diffraction studies. The Lewis acidity of compounds 1 and 3 are determined by conducting fluoride ion affinity experiments using UV-Vis spectrophotometry and multinuclei NMR spectroscopy. Compounds 1 and 3 exhibited selective binding to fluoride anion but did not interact with other halides (Cl- and Br-). Quantum chemical calculations were performed to understand the structure and nature of bonding interactions in these compounds, as well as to comprehend the specific bonding affinity to fluoride over other halide ions.

Mechanistic model of minute virus of mice elution behavior in anion exchange chromatography purification.

This study aimed to propose a methodology for developing a mechanistic model for viral clearance of the minute virus of mice (MVM) on flow-through anion exchange (AEX) chromatography. Protein surface analysis was applied to investigate the possibility of molecular interaction between the recombinant biotherapeutic and MVM. The protein product-free Tris buffers were spiked with MVM, and the MVM elution profile from AEX chromatography was quantitatively analyzed using quantitative polymerase chain reaction (qPCR) for pooled fractions. GoSilico™ Chromatography Modeling Software was applied to develop the mechanistic models for MVM species. For evaluating the visual fit of the developed model, the R2 of intact MVM virions and uncoated capsids between the simulated and measured amount in each fraction are 0.880 and 0.948, respectively. Response surface plots of logarithmic reduction values (LRV) against pH and conductivity in loaded sample were generated to show the range for suitable loaded sample conditions for achieving a good LRV. To evaluate the applicability of the developed MVM elution model to a recombinant biotherapeutic, two demonstrations of AEX chromatography purification were performed with a loaded sample of a model monoclonal antibody. The peaks of the MVM species in the elution step of both runs were accurately simulated by the developed model. In addition, to assess the possibility of molecular interaction between the virus and the target protein significantly affecting the MVM elution behavior, the antibody's surface was evaluated in terms of hydrophobicity/hydrophilicity using surface analysis.