Cationic Ions Research Articles

Increasing Cation Ion Symmetry Reduces Ionic Liquid Ordering in Thin Films.

Ionic liquids have been shown to form extended ordered structures near surfaces and in bulk. Identifying fundamental driving force(s) for this organization has been elusive. In this paper, we test a hypothesis that the ionic liquid asymmetry, inherent in many of the IL formulations to frustrate crystallization, is a significant contributor to the observed ordering. We have carried out measurements to track the ordering of ionic liquids composed of "spherical" cations, namely, tetraoctylphosphonium ([P8888]) and tetra(propoxymethyl)phosphonium [P(3O1)4] paired with tetracyanoborate anion [B(CN)4]. Analysis of the infrared signatures for films of these ionic liquids shows very little evidence of ordered structures. These liquids instead remain in a more isotropic environment even when confined to volumes of few micrometer dimensions.

PE/PP fibrous adsorbents with bifunctional groups of tertiary amine and phosphate prepared by electron beam induced co-grafting for heavy metal adsorption of both cationic and anionic forms in acidic conditions.

A novel fabric adsorbent having bifunctional groups of tertiary amine and phosphate was prepared by co-graft polymerization of 2-diethylaminoethyl methacrylate (NMA) and 2-hydroxyethyl methacrylate phosphate (PMA) onto a polyethylene/polypropylene nonwoven fabric (PE/PP NF) under low-energy electron beam acceleration. The process involved pre-irradiating the fabric and immersing it in the comonomer solution for grafting. The kinetics of radiation-induced graft polymerization at a total dose of 100 kGy was investigated. For pre-irradiation at 100 kGy, the optimum condition offering highest degree of grafting was at 12 wt% of NMA, 8 wt% of PMA and 4 h of reaction time. The adsorption of anions using hydrogen chromate (HCrO4−) or Cr(VI) and cations using lead (Pb(II)), cadmium (Cd(II)) and copper (Cu(II)) in aqueous solution was carried out. The results demonstrated that the bifunctional adsorbent was able to adsorb both heavy metal anionic and cationic ions from water. The co-grafted adsorbents with tertiary amine and phosphate were able to adsorb 85% Cr(VI) anion and 29% Pb(II) cations from mixed Cr(VI) and Pb(II) solution at pH 3.0 and 71% Pb(II), 13% Cd(II) and 31 % Cu(II) from mixed Pb(II), Cd(II) and Cu(II) solution at pH 5.0. The unique achievement of this study is its hypothesis that a bifunctional adsorbent can be prepared from radiation-induced graft polymerization of two different monomers onto NF, along with proof that the prepared bifunctional adsorbent can actually absorb both cationic or anionic heavy metals forms. Additionally, the adsorbent's preparation offers a rapid and straightforward one-step grafting technique. Therefore, the new bifunctional adsorbents can remove heavy metal ions in aqueous solution, either in the cation or anion form, thus offering highly promising applications in industrial wastewater treatment.

Structural Studies on Mycobacterial NudC Reveal a Class of Zinc Independent NADH Pyrophosphatase

Non-tuberculous mycobacteria (NTM) have emerged as an increasing threat to public health, due to the extreme antibiotic resistance. NADH pyrophosphatase (NudC) was proposed involving in mycobacterial resistance to the first line anti-tubercular drug isoniazid (INH) or its analog ethionamide (ETH), by hydrolyzing their NAD modified active forms (NAD-INH and NAD-ETH). In this study, we performed enzymatic and structural studies on NudC from M. abscessus (NudCMab), which is highly resistant to isoniazid and emerging as the most worrisome NTM. We determined the crystal structures of NudCMab in apo form, substrate NAD-bound form and product AMP-bound form. We observed the mode for the Nudix motif of NudCMab capturing the pyrophosphate group of NAD mediated by three divalent cation ions, which provides details for understanding the mechanism on NudC hydrolyzing NAD(H) or NAD-capped substrate. Interestingly, our structures revealed a novel subclass NudC from mycobacteria characterized by a unique arginine residue on the conserved QPWPFPxS motif, as well as a unique tower domain that replaces a well-defined zinc-binding motif in E.coli NudC and catalytic domain of mammalian Nudt12. Thus, our structural studies on NudCMab not only present a class of zinc independent NADH pyrophosphatase in mycobacteria, but also may facilitate the design of NudC inhibitors for the treatment of mycobacteria infections in combination with INH or ETH.

Tunable double emission of Sb3+/Mn2+ doping stabilized organic-inorganic hybrid zinc-based halides

Low-dimensional organic-inorganic hybrid metal halides (OIHMHs) have attracted much attention lately in contrast to all-inorganic metal halides because of their excellent photophysical properties and tunable emission wavelengths. Zn-based metal halides have the following advantages: simplicity of synthesis, wide bandgap, and excellent chemical stability. Therefore, they are well-suited as host materials for photoluminescence by cation ion doping. We have successfully synthesized intrinsically non-emissive 0D (PPZ)ZnCl4 [PPZ (1-phenylpiperazine) = C10H14N2], and by mono/co-doping with Mn2+ and Sb3+, interesting luminescence phenomena have been produced. Single-doped Mn2+ / Sb3+ shows distinctive green and single orange emission, respectively. However, the co-doped Mn2+ and Sb3+ appeared as dynamic double emission peaks at 530nm and 670nm. Therefore, the co-doped crystals showed luminescence from two different luminescence centers ([MnCl4]2- and [SbCl4]-). We used DFT to calculate the DOS (density of states) of co-doped crystals, which results in energy transfer between Mn2+ and Sb3+. All of the above samples showed high stability after being left for two months. In addition, two different luminescence centers can be produced by the adjustment of the excitation of the co-doped (PPZ)ZnCl4: Sb0.12Mn0.08 samples, which is a distinguishable and obvious photoluminescence phenomenon having great potential preparation of advanced anti-counterfeiting materials in the future.

Impact of calcium-reinforcement on stability, bioavailability, and bioactivity of quercetin-loaded zein/alginate-pectin nanoparticles.

Cationic calcium ions can crosslink anionic alginate and pectin molecules. It was hypothesized that calcium crosslinking would improve the stability and functionality of biopolymer nanoparticles consisting of zein cores coated by alginate-pectin shells. The effects of calcium ion addition on the structural, physicochemical, and gastrointestinal properties of quercetin-loaded zein/alginate-pectin nanoparticles were therefore investigated. The nanoparticles remained stable to aggregation at calcium ion concentrations of 9 mmol/L or less but aggregated and sedimented at higher concentrations. Calcium ion reinforcement increased the particle dispersion stability even at NaCl concentrations up to 1.4 molL-1. The presence of the calcium ions also reduced quercetin release during the early stages of simulated gastrointestinal digestion but increased its release during the later stages. The relatively high release (56.1%) of quercetin from the calcium-reinforced nanoparticles after digestion resulted in higher intracellular antioxidant activities. The pharmacokinetics of the encapsulated quercetin was measured after its oral administration to rats. The maximal concentration (Cmax) of quercetin in rat plasma for calcium-reinforced nanoparticles was 6.1% higher than non-reinforced nanoparticles; the half-life (t1/2) increased by 17.5%, and the mean retention time (MRT) was 10.0% higher (P < 0.05). These results suggest that calcium ion addition improved the performance and bioavailability of nutraceutical-loaded biopolymer nanoparticles. This might find application in the food and beverage industry. © 2024 Society of Chemical Industry.

Unconventional exchange bias and enhanced spin pumping efficiency due to diluted magnetic oxide at the Co/ZnO interface

Exchange bias (EB) is normally created by the interfacial exchange coupling at a ferromagnetic/antiferromagnetic (FM/AFM) interface. FM/AFM interfaces have also been proved to perform enhanced spin angular momentum transfer efficiency in spin pumping (SP), compared with typical FM/nonmagnetic interfaces. Here, we report an unexpected EB and enhanced SP between a ferromagnet and semiconductor. Considerable EB has been observed in Co films grown on ZnO single crystal due to the interface antiferromagnetism of the Zn1−xCoxO (x depends on the Co solubility limit in ZnO) layer. Moreover, SP measurements demonstrate a giant spin pumping efficiency at the Co/ZnO interface with a bump (spin mixing conductance Geff↑↓= 28 nm−2) around the blocking temperature TB ∼ 75 K. The enhanced SP is further confirmed by inverse spin Hall effect measurements and the spin Hall angle θISHE of Zn1−xCoxO is estimated to be 0.011. The bound magnetic polarons with s–d exchange interaction between donor electrons and magnetic cation ions in Zn1−xCoxO play a key role in the formation of antiferromagnetism with giant Geff↑↓. Our work provides a new insight into spin physics at FM/semiconducting interfaces.

Phase separation behavior and thermal degradation analysis of DETA/DEA/DMAC biphasic absorbent

Thermal stability is crucial for maintaining the efficient performance and low regeneration energy of biphasic absorbents, while the synergistic degradation reactions and condition fluctuations could significantly influence the thermal degradation process of biphasic solutions. In this research, a typical amide-based biphasic absorbent diethylenetriamine(DETA)/diethanolamine(DEA)/N, N-dimethylacetamide(DMAC) with low regeneration energy, was applied in a thermal degradation investigation. The thermal stability of active amine in DETA/DEA/DMAC was superior to 30 wt% MEA, 7 M DETA solution, and other biphasic absorbents, with a 19.9 % lower amine degradation ratio compared to 7 M DETA. The primary thermal degradation products in DETA/DEA/DMAC with and without CO2 were analyzed using Cation Ion Chromatography (IC) and 13C Nuclear Magnetic Resonance (NMR). A series of synergistic reactions between DETA and DMAC, with DMAC being an inducer, was revealed in thermal degradation of DETA/DEA/DMAC, leading to accelerated DETA degradation and DEA formation. Various operational conditions including CO2 loading and degradation temperature were considered to build a systemic impact mechanism on thermal degradation for biphasic absorbents. Before phase separation, CO2 absorption and increasing temperature significantly exacerbated DETA degradation. However, phase separation behavior was found to effectively prevent the synergistic degradation reactions in the solution, leading to a 27.4 % reduction in the DETA degradation ratio of the aqueous phase after phase separation. Moreover, it achieved a 24.1 % reduction of the DETA degradation ratio caused by rising temperature in the solution after phase separation. Therefore, it is essential to ensure the completion of phase separation for biphasic solvents before entering the stripper in applications. After thermal degradation, the regeneration rate and cyclic capacity of DETA/DEA/DMAC were strengthened, which was 84.9 % and 63.3 % higher than that of 30 wt% MEA, respectively

Tubulin interaction at tubulin-binding sequence 1 (TBS1) is required for proper surface expression and TRPV1 channel activity

TRPV1, a polymodal and nonselective cation channel has unique gating mechanisms which is regulated by supramolecular complexes at the plasma membrane formed with membrane proteins, lipids and kinase pathways. Crosstalk between microtubule cytoskeleton with TRPV1 at various level has been established. Previously we demonstrated that the positively-charged residues present at specific tubulin-binding stretch sequences (i.e. TBS1 and TBS2, AA 710–730 and 770–797 respectively) located at the C-terminus of TRPV1 are crucial for tubulin interaction and such sequences have evolutionary origin. The nature of TRPV1-tubulin complex and its functional importance remain poorly understood. Here, we made several mutations in the TBS1 and TBS2 regions and characterized such mutants. Though these mutations reduce tubulin interaction drastically, a low and basal-level of tubulin interaction remains with these mutants. Substitution of positively-charged residues (Lys and Arg) to Ala in the TBS1, but not in TBS2 region results in reduced ligand-sensitivity. Such ligand-sensitivity is altered in response to Taxol or Nocodazole. We suggest that tubulin interaction at the TBS1 region favours channel opening while interaction in TBS2 favours channel closure. We demonstrate for the first time the functional significance of TRPV1-tubulin complex and endorse microtubule dynamics as a parameter that can alter TRPV1 channel functions. These findings can be relevant for several physiological functions and also in the context of chemotherapy-induced neuropathic pain caused by various microtubule stabilizing chemotherapeutic drugs. Thus, this characterization may indicate TRPV1 as a potential therapeutic target relevant for chemotherapeutic drug-induced peripheral neuropathies, neurodegeneration and other neurological disorders.

Reversible Li-ion trade-off in ultrathick sulfur cathodes for practical lean Li–S batteries

The use of low electrolyte volume is beneficial to improve energy density but severely limits access over obscured sulfur, along with sluggish ion kinetics and aggravated polarization, as the ion imbalance across the multicomponent interface of thick sulfur cathodes at a lean electrolyte viciously dominates the sulfur electrokinetics. Herein, we demonstrate that an ion imbalance at the interfaces of a thick electrode with a lean electrolyte can be compensated by the ion trade-off strategy utilizing a cationic ion conductive active binder. It ensures sustained lithium-ion donation/release over the vicinity of slow electrolyte percolation to realize an ion-enriched sulfur–binder–electrolyte interface. The in-situ evolved ionic interface essentially activates the inaccessible sulfur, bringing about additional capacity and low ion and charge transfer resistances. The active binder adopts sulfur cathodes housing 8.1 mg cm–2 with an E/S ratio of 6 µL mg–1 electrochemically utilized 60.89 % sulfur, corresponding to a 1020 mAh g–1 capacity. The lean Li–S pouch cell delivers an energy density of 324 Wh kg–1, demonstrating the efficacy of ion trade-off to ease the interfacial barrier. This study would open up a new paradigm in potentially designing thick electrodes for multiple high energy density batteries.

In Situ Synthesized HOF Ion Rectification Membrane with Ultrahigh Permselectivity for Nanofluidic Osmotic Energy Harvesting

AbstractThe utilization of salt concentration gradients as a renewable energy source represents a pivotal solution to the energy crisis. However, it is a persistent challenge to fabricate high‐performance ion permeable membranes with excellent ion permselectivity. In this work, hydrogen‐bonded organic framework (HOF) is in situ growth on anodic aluminum oxide (AAO) via chemical‐binding and solution‐processing strategy. The hydrogen bonding and π–π interactions forming the porous structure and the internal unprotonated carboxyl groups endow the HOF with superior cation selectivity and ion permeability. Furthermore, benefiting from the remarkable asymmetry of the prepared nanofluidic membrane arising from structure and charge of AAO and HOF, the HOF/AAO presents outstanding ion current rectification (ICR) characteristic, which can eliminate the ion concentration polarization (ICP) and power loss. Therefore, an impressive output power density with 500‐fold NaCl gradient is achieved as 75.2 W m−2 using the as‐prepared HOF/AAO, which is superior to most of reported membranes (7.0–40.0 W m−2). To show the critical role of HOF, 2D and 3D MOF with the same monomers are also synthesized, achieving decreased power densities of 36.2 and 58.3 W m−2 respectively. The present work provides a novel strategy to develop high‐performance nanofluidic ICR membranes for osmotic energy harvesting.

Fabricating whole pine needles biomass with phenylhydrazine-4-sulphonic acid for effective removal of cationic dyes and heavy metal ions from wastewater

We applied a holistic, sustainable, and green approach to develop an effective multipurpose adsorbent from whole pine needles (PNs), a forest waste lignocellulosic biomass. The PNs were oxidized and modified with phenylhydrazine-4-sulphonic acid (ɸHSO3H) to OPN-ɸHSO3H. The latter was characterized and tested as an adsorbent for cationic dyes, malachite green (MG), methylene blue (MB), crystal violet (CV), and metal ions (Hg2⁺ and Pb2⁺). The adsorption followed different kinetic models: Elovich for MG and MB, pseudo-second-order for CV, and pseudo-first-order for Hg2⁺ and Pb2⁺. Langmuir isotherm indicated maximum adsorption capacities of 303.4 ± 8.91 mgg−1 (MG), 331.4 ± 17.50 mgg−1 (MB), 376.6 ± 22.47 mgg−1 (CV), 210.8 ± 28.86 mgg−1 (Hg2⁺), and 172.9 ± 20.93 mgg−1 (Pb2⁺) within 30 min. Maximum removal efficiencies were 99.0% (MG), 98.0% (MB), 96.04% (CV), 95.5% (Hg2⁺), and 89.8% (Pb2⁺). The adsorbent demonstrated significant regeneration and reusability over ten cycles, proving highly efficient for both cationic dyes and metal ions, with wide potential for practical applications where more than one adsorbate is present.

Multifunctional Chitosan Nanofiber-Based Sponge Materials Using Freeze-Thaw and Post-Cross-Linking Method.

The fabrication of porous sponge materials with stable structures via cross-linking diverse polymers presents significant challenges due to the simultaneous requirements for phase separation as a pore-forming step and cross-linking reactions during the fabrication process. To address these challenges, we developed a sponge material solely from natural-based polymers, specifically chitosan nanofibers (CSNFs) and dialdehyde carboxymethyl cellulose (DACMC), employing a straightforward, eco-friendly technique. This technique integrates a facile freeze-thaw method with subsequent cross-linking between CSNFs and DACMC. This method effectively addresses the difficulties associated with pore formation in materials, which typically arise from the rapid formation and precipitation of polyionic complexes during the mixing of anionic and cationic polymers, using ice crystals as a rigid template. The resultant sponge materials exhibit remarkable shape recoverability in their wet state and maintain light, stable porosity in the dry state. Furthermore, in comparison to commonly used commercial foams, this composite porous material demonstrates superior fire retardancy and thermal insulation properties in its dry state. Additionally, it shows effective adsorption capacities for both cationic and anionic dyes and metal ions. This method of using biobased polymers to produce porous composites offers a promising avenue for creating multifunctional materials, with potential applications across various industries.

Preparation and characterization of starch carbamate modified natural sodium alginate composite hydrogel blend formulation and its application for slow-release fertilizer

The exploration of environmentally friendly slow-release fertilizer (SRF) based on natural bio-polymers is of great importance in the development of modern agriculture and horticulture. Herein, a novel starch carbamate (SC) modified sodium alginate (SA) hydrogel (SC/SAH) was prepared utilizing as-synthesized SC and natural SA through the cationic ions crosslinking method and ultimately the corresponding slow-release fertilizer (SC/SAH-SRF) was successfully developed by immersing the dried SC/SAH matrix into saturated urea solution. Due to the low gelation temperature and high viscosity of the synthesized SC, the formed SC/SAH exhibits significantly enhanced properties including excellent water absorbency up to 8.02 g/g with considerable repeatability, abundant pore structure and high hydrophilicity compared with the neat SAH and natural starch based hydrogel (NS/SAH). Accordingly, the SC/SAH leads to higher urea loading amount ∼ 1.28 g/g. Importantly, the resultant SC/SAH-SRF also shows superior slow-release performance, yielding a cumulative urea release of only 61.6 % within 10 h and almost completely release >16 h in water, what's more, only 58.5 % of the urea releases within 25 days and exceeding 50 days for complete release in soil column assays. The slow-release of urea from SC/SAH-SRF well complies for the first-order kinetics and accomplishes via a non-Fickian diffusion process. Moreover, the pot experiment demonstrates that the SC/SAH-SRF has higher growth promotion role for the maize seedlings than those of others. Consequently, this work provides a novel strategy for preparing environmentally friendly SRF by blending modified starch and hydrogel.

Combined Approaches for the Remediation of Cadmium- and Arsenic-Contaminated Soil: Phytoremediation and Stabilization Strategies

The prolonged duration of phytoremediation poses a risk of heavy metal dispersal to the surrounding environment. This study investigated a combined remediation approach for cadmium (Cd)- and arsenic (As)-contaminated soil by integrating phytoremediation with stabilization techniques. Bidens pilosa was utilized as the phytoremediator, and steel slag, pyrolusite, and FeSO4 were employed as stabilizing agents in the pot experiments. Key metrics such as soil moisture content, root length, plant height, and heavy metal concentrations in Bidens pilosa were measured to evaluate the remediation efficacy. Additionally, the bioavailability, leaching toxicity, and chemical forms of Cd and As, along with other soil properties, were analyzed. The results indicated that the optimal restoration effect was achieved by combining steel slag, pyrolusite, and FeSO4 with stabilizers in a ratio of 2:1:10. Additionally, the optimal dosage of these materials was found to be 9% by weight. Mechanistic studies, including heavy metal speciation analysis, X-ray photoelectron spectroscopy (XPS), and microbial community diversity analysis, revealed that the stabilization effects were primarily due to the interactions of anionic and cationic ions, chelation by organic acids secreted by plant roots, and enhanced microbial activity. A cost–benefit analysis demonstrated the technical, economic, and commercial viability of the combined remediation approach.

Synergistic effect of CTA+ and Br- on defect-free TSV filling by Cu electrodeposition

Suppressing additives for Cu electrodeposition play a critical role in inducing bottom-up filling in micrometer-scale features such as through-silicon vias (TSVs). This study explores the adsorptive behaviors of cetyltrimethylammonium cation (CTA+) and bromide ion (Br-) and their application to defect-free TSV filling. Electrochemical analyses reveal that both CTA+ and Br- suppress Cu electrodeposition, with only CTA+ exhibiting negative differential resistance (NDR) behavior. The addition of Br- to CTA+ enhances the suppression effect while maintaining the NDR behavior of CTA+. TSV filling experiments demonstrate that the NDR behavior of the CTA+ and Br- combination induces the passive-active transition on the sidewalls of TSVs, which is essential for Cu bottom-up filling. The effects of CTA+ and Br- concentrations on the passive-active transition are also investigated, showing that CTA+ determines the height at which the passive-active transition occurs, while Br- enhances suppression to inhibit Cu growth on the sidewalls in the active region. Based on these behaviors, the optimal CTA+-Br- combination leads to successful bottom-up filling in TSVs. The mechanisms of TSV filling with CTA+ and Br- are suggested based on electrochemical analyses and gap-filling results. The active region at the TSV bottom, formed via selective breakdown of suppressing adsorbates, is filled while effectively inhibiting Cu deposition on the sidewalls, followed by filling the remaining portion of TSVs with vertical Cu growth.

Thermal Vapor Deposition of a Hydrophobic and Gas-Permeable Membrane on Zirconium Phosphate Cation Exchanger: An Oral Sorbent for the Urea Removal of Kidney Failure.

An oral sorbent with high capacity for NH4+ is desirable in lowering the blood urea level and mitigating the dialysis burden for end-stage kidney disease (ESKD) patients. Zirconium phosphate (ZrP) is an amorphous cation ion exchanger with high NH4+ binding capacity as a sorbent material, but its selectivity to remove NH4+ is limited in the presence of other competing ions in water solution. We previously have developed a gas-permeable and hydrophobic perfluorocarbon coating on ZrP, which improves ZrP's NH4+ selectivity. However, the coating preparation procedure, a wet chemistry approach, is complicated and time-consuming, and more importantly, the large amount of usage of acetone poses a concern for the application of ZrP as an oral sorbent. In this study, we developed a solventless coating protocol that effectively coats ZrP with tetraethyl orthosilicate (TEOS) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FOTS) via thermal vapor deposition (TVD) in a simplified manner. X-ray photoelectron spectroscopy (XPS) and contact angle measurements verify the two coatings are successfully deposited on the ZrP surface, and the coating condition was optimized based on an in vitro static binding study. The dynamic binding study of competing ions on Na-loaded ZrP with TVD coatings yields a maximum NH4+ removal (∼3.2 mequiv/g), which can be improved to ∼4.7 mequiv/g if H-loaded ZrP under the same coating condition is used in basic stock solutions. More importantly, both materials barely remove Ca2+ and show excellent acid resistance. The significant improvement in the NH4+ binding capacity and selectivity reported here establishes a highly promising surface modification approach to optimize oral sorbents for ESKD patients.

Effect of Surfactants on 1,2-Dichloroethane-in-Water Droplet Impacts at Electrified Liquid-Liquid Interface

In this work, we used the electrified liquid-liquid interface (eLLI) to study the fusion of DCE-in-water organic droplets (soft particles) upon coming into contact with the soft interface. Our focus was to define the effect of the neutral (1-tetradodecanol) and ionic (cetyltrimethylammonium bromide and sodium dodecylsulfonate) surfactants that stabilize the colloidal solution on the electroanalytical output of the impact events. The electrochemically and interfacially active salt used in our work (tetramethylammonium tetrakis(4-chlorophenyl)borate) was always initially dissolved in the organic phase droplets. When the potential drop at the interface was set below the formal Galvani potential of the tetramethylammonium cation ion transfer, we observed ionic current events upon the fusion of the droplets at the eLLI, as studied by chronoamperometry. This phenomenon was found to be severely affected by the surfactants. Our system was investigated with several methods, including cyclic voltammetry, chronoamperometry, interfacial tension measurements, and finally zeta potential and droplet size distribution measurements based on dynamic light scattering.

Electrochemical Reduction of N2 to Ammonia Promoted by Hydrated Cation Ions: Mechanistic Insights from a Combined Computational and Experimental Study.

Alkali ions, major components at the electrode-electrolyte interface, are crucial to modulating reaction activity and selectivity of catalyst materials. However, the underlying mechanism of how the alkali ions catalyze the N2 reduction reaction (NRR) into ammonia remains elusive, posing challenges for experimentalists to select appropriate electrolyte solutions. In this work, by employing a combined experimental and computational approach, we proposed four essential roles of cation ions at Fe electrodes for N2 fixation: (i) promoting NN bond cleavage; (ii) stabilizing NRR intermediates; (iii) suppressing the competing hydrogen evolution reaction (HER); and (iv) modulating the interfacial charge distribution at the electrode-electrolyte interface. For N2 adsorption on an Fe electrode with cation ions, our constrained ab initio molecular dynamic (c-AIMD) results demonstrate a barrierless process, while an extra 0.52 eV barrier requires to be overcome to adsorb N2 for the pure Fe-water interface. For the formation of *NNH species within the N2 reduction process, the calculated free energy barrier is 0.50 eV at the Li+-Fe-water interface. However, the calculated barrier reaches 0.81 eV in pure Fe-water interface. Furthermore, experiments demonstrate a high Faradaic efficiency for ammonia synthesis on a Li+-Fe-water interface, reaching 27.93% at a working potential of -0.3 V vs RHE and pH = 6.8. These results emphasize how alkali metal cations and local reaction environments on the electrode surface play crucial roles in influencing the kinetics of interfacial reactions.

Acetate anions intercalated Fe/Mg-layered double hydroxides modified biochar for efficient adsorption of anionic and cationic heavy metal ions from polluted water

The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac− as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations.

Axonal and Glial PIEZO1 and PIEZO2 Immunoreactivity in Human Clitoral Krause's Corpuscles.

Krause's corpuscles are typical of cutaneous mucous epithelia, like the lip vermillion or the glans clitoridis, and are associated with rapidly adapting low-threshold mechanoreceptors involved in gentle touch or vibration. PIEZO1 and PIEZO2 are transmembrane mechano-gated proteins that form a part of the cationic ion channels required for mechanosensitivity in mammalian cells. They are involved in somatosensitivity, especially in the different qualities of touch, but also in pain and proprioception. In the present study, immunohistochemistry and immunofluorescence were used to analyze the occurrence and cellular location of PIEZO1 and PIEZO2 in human clitoral Krause's corpuscles. Both PIEZO1 and PIEZO2 were detected in Krause's corpuscles in both the axon and the terminal glial cells. The presence of PIEZOs in the terminal glial cells of Kraus's corpuscles is reported here for the first time. Based on the distribution of PIEZO1 and PIEZO2, it may be assumed they could be involved in mechanical stimuli, sexual behavior, and sexual pleasure.