Replacement Of Sodium Ions Research Articles

Replacing Sodium Ions with Protons in Vanadophosphate Glass: Suppression of Electronic Conduction by Local Structural Change around Vanadium Ions

Replacing Sodium Ions with Protons in Vanadophosphate Glass: Suppression of Electronic Conduction by Local Structural Change around Vanadium Ions

Desulfurization steel slag improves the saline-sodic soil quality by replacing sodium ions and affecting soil pore structure

Flue gas desulfurization steel slag (DS), a solid waste produced by coal power plants and steelworks, was proposed as an amendment for the remediation of saline-sodic soil. A pot experiment including three dosages of DS alone (1%, 5%, 10% w/w) and their combination with fulvic acid (FA, 1%, w/w) was conducted to evaluate the potentials of DS as an amendment and to explore remediation mechanism of DS combined with FA on saline-sodic soil. The soil salinity, nutrition, pore structure, water retention, consistency, and desiccation cracking of DS and FA-amended soils were determined. Application of DS resulted in a significant reduction of pH, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of saline-sodic soil. The DS amendment significantly increased the 6–15 μm pore volume of soil. The combination application of DS and FA showed better effect than the DS alone. The DS amendments at 5% and 10% significantly increased the field water capacity, permanent wilting point, and available water content of the soil, whereas significantly decreased the plastic limit, liquid limit, and plastic index. The DS alone and combined with FA could effectively control the development of desiccation cracking, reduced significantly the crack area density and average width of cracks of the soil. Consequently, the improvement of alkalinity and soil physical properties by DS amendment significantly increased the yield of alfalfa grown on saline-sodic soil. The remarkable improvement of physical properties of saline-sodic soil contributed to the decrease of SAR and ESP by the Ca2+ in DS replacing the Na + at soil colloid sites. Our results suggested that DS amendments alone or combined with fulvic acid have great potential as saline-alkali soil amendment.

Carbonized Nickel Complex of Sodium Pectate as Catalyst for Proton-Exchange Membrane Fuel Cells.

Sodium pectate derivatives with 25% replacement of sodium ions with nickel ions were obtained by carbonization to temperatures of 280, 550, and 800 °C, under special protocols in an inert atmosphere by carbonization to temperatures of 280, 550, and 800 °C. The 25% substitution is the upper limit of substitution of sodium for nickel ions, above which the complexes are no longer soluble in water. It was established that the sample carburized to 550 °C is the most effective active element in the hydrogen-oxidation reaction, while the sample carbonized up to 800 °C was the most effective in the oxygen-reduction reaction. The poor performance of the catalytic system involving the pectin coordination biopolymer carbonized up to 280 °C was due to loss of proton conductivity caused by water removal and mainly by two-electron transfer in one catalytic cycle of the oxygen-reduction reaction. The improved performance of the system with coordination biopolymer carbonized up to 550 °C was due to the better access of gases to the catalytic sites and four-electron transfer in one catalytic cycle. The (Ni-NaPG)800C sample contains metallic nickel nanoparticles and loose carbon, which enhances the electrical conductivity and gas capacity of the catalytic system. In addition, almost four-electron transfer is observed in one catalytic cycle of the oxygen-reduction reaction.

Synergistic inhibition of polyethylene glycol and potassium chloride in water-based drilling fluids

Mud shale hydration and swelling are major challenges in the development of water-based drilling fluids (WBDFs). In this work, the inhibition performance and inhibition mechanism of polyethylene glycol (PEG) and potassium chloride (KCl) were investigated by hot rolling recovery tests, linear swell tests, Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption spectrophotometry and X-ray photoelectron spectroscopy. The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl. Compared to the d-spacing of Na-montmorillonite (Na-Mt) with PEG or KCl, the d-spacing of Na-Mt with PEG+KCl was lower, which indicates that KCl and PEG have synergistic inhibition effect. This synergistic effect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt. Based on the above experimental results and analysis, a method for optimizing PEG and KCl concentrations was proposed and further verified by rheological and hot rolling recovery tests of WBDFs. Hence, the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.

Synthesis and mechanism research of a new low molecular weight shale inhibitor on swelling of sodium montmorillonite

AbstractShale gas as green and clean energy is attracting more interest. However, shale hydration and swelling have become the major challenges using water‐based drilling fluids, replacing oil‐based drilling fluids, for developing shale gas. In this work, a low molecular weight branched polyamine (NETS) as clay swelling inhibitor was synthesized. The NETS performed excellent inhibition property by linear expansion experiments and cuttings hot‐rolling recovery. The inhibition mechanism of NETS was investigated using X‐ray diffraction, fourier transform infrared spectroscopy, cation exchange capacity, X‐ray photoelectron spectroscopy, scanning electron microscopy, and zeta potential. The results show that the NETS can adsorb on Na‐Mt, decrease the basal spacing of wet Na‐Mt from 1.91 to 1.43 nm, and replace majority sodium ions from interlayer of Na‐Mt. However, replaceability of sodium ions and inhibition of water molecules of ethylenediamine are worse than NETS. These indicate that the primary amines of NETS had strong interaction with Na‐Mt, tensed clay layers and decrease the basal spacing. The combination of long hydrophobic chain and primary amines makes NETS to adsorb on surface of Na‐Mt, intercalate into interlayer of Na‐Mt with tilted monolayer arrangement, and replace sodium ions. The more the number of primary amine groups, the better the inhibition performance. Therefore, NETS has a great potential to be an outstanding shale inhibitor of water‐based drilling fluids in the future.

Investigation of the inhibition mechanism of the number of primary amine groups of alkylamines on the swelling of bentonite

The inhibition mechanism of alkylamines that have different numbers of primary amine groups adsorbed on sodium bentonite has been investigated using isothermal adsorption, adsorption kinetics, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (EA), cation exchange capacity (CEC), thermogravimetric analysis (TGA), linear expansion experiments and rolling recovery. The saturated adsorption capacity of alkylamines on sodium bentonite decreased with the increase in the number of primary amine groups. The adsorption rate constant increases rapidly with the increase in the number of primary amine groups on the premise that they are both water-soluble and hydrophobic. A flat-lying monolayer of each alkylamine was intercalated, replacing sodium ions in the interlayer and becoming firmly embedded in the interlayer space of sodium bentonite between the primary amine groups and silicon-oxygen tetrahedra. As a result, the water molecules present in the clay interlayer space were expelled, and the interlayer space of the clay decreased to the maximum extent. The inhibition performance of alkylamines on bentonite clearly increases with the increasing of number of primary amine groups. Therefore, a mixture of alkylamines with multiple primary amine groups is a promising intercalating inhibitor that can be used along with water-based drilling fluids has broad application prospects.

Features of the optical properties of diffusion layers obtained by successive replacement of sodium ions with copper and silver ions in silicate glass

It is experimentally shown that, when copper and silver ions are successively incorporated into silicate glass by the method of ion exchange, followed by heat treatment, metallic nanoparticles whose structure and composition depend on its temperature are formed in the glass. When the heat-treatment temperature is lower than the glass-transition temperature, spherical nanoparticles of silver and copper are formed in the glass; when the temperature is above the glass-transition temperature, nanostructures are formed that consist of a copper core and a silver shell. The absorption spectra of such structures are compared with the calculated spectrum of their absorption cross section.

Controlled Self-Assembly and Luminescence Characteristics of Eu(III) Complexes in Binary Aqueous/Organic Media

Luminescence of sodium tetrakis(naphthoyl trifluoroacetonato) europium(III) (Na[Eu(nta)4]) in binary aqueous-ethanol media is quenched continuously with an increase in the water content, which is ascribed to commonly observed relaxation of photoexcited lanthanide complexes through vibrational coupling with coordinating water. Meanwhile, replacement of sodium ion with an ammonium amphiphile 1 gives a lipid complex 1[Eu(nta)4] which shows distinct changes: its luminescence quantum yield Φ is remarkably increased to ~0.6 above the water content of ~60 vol. %. This unusual enhancement in luminescence intensity occurs in response to self-assembly of 1[Eu(nta)4] into nanoparticles. The lipid counterions provide a hydrophobic atmosphere inside nanoparticles, and they simultaneously form monolayers on the nanoparticle surface that enhance dispersion stability. The size of nanoparticles is tunable depending on the volume fraction of water in the binary media. The lipid-assisted self-assembly of lanthanide complexes provides a unique means to fabricate luminescent nanomaterials, and this approach will be widely applied to fabricate functional coordination nanomaterials.

Are dopamine receptors present on human lymphocytes?

The characteristics of [3H] spiperone binding to human lymphocytes have been examined. The haloperidol displaceable component of [3H] spiperone binding to human lymphocytes was not saturable, and stereoselective displacement by the isomers of butaclamol was not observed. These was no correlation between the ability of known dopamine active drug to cause displacement of the ligand and their rank order of potency. Chloroquine, a drug with no dopaminergic action, was the most potent displacing agent examined. Fragmentation of the cells caused a marked decrease in the haloperidol displaceable component of [3H] spiperone binding, and saturable binding to the lymphocyte membrane fragments was not observed. lysis of cells after equilibrium incubation with [3H] spiperone caused a marked reduction in the haloperidol displaceable component of ligand binding. Association of [3H] spiperone with lymphocytes was unaffected by the metabolic inhibitor iodoacetate or by replacement of sodium ions by lithium ions in the incubation medium, suggesting that such association did no involve an active process. We cannot confirm the existence of dopamine receptors on the surface of human lymphocytes. We suggest that the apparent association of [3H] spiperone with lymphocytes is due to some passive uptake process causing accumulation of the ligand within the cells.

이온교환에 의한 칼슘알지네이트 섬유의 제조

Calcium alginate fiber were prepared by wet spinning of various conditions, including different concentrations of sodium alginate solution and <TEX>$CaCl_2$</TEX> concentrations for coagulating the fiber through an absorption of calcium ion. The absorption of calcium ion during the coagulating step lead to solidify the fibers by the replacement of sodium ion with calcium ion to produce some crosslinking. The concentration of calcium ion in the calcium alginate fiber seems to be well related to the mechanical and physical property of the fiber, such as fiber strength moisture regain, and degree of swelling. The tensile strength of calcium alginate fiber was increased along with the increasing amount of sodium alginate solution. According to EDS analysis, 7 wt% <TEX>$CaCl_2$</TEX> coagulation bath resulted in more calcium ion in the fiber compared to 3 wt% <TEX>$CaCl_2$</TEX> coagulation bath. The decomposition temperature of calcium alginate fiber was <TEX>$199^{\circ}C$</TEX>, which <TEX>$14^{\circ}C$</TEX> higher than that of sodium alginate.

Dynamics of counterion binding during acoustic nebulisation of surfactant solutions

A metal ion (Cu 2+) and a complex copper species, copper (II) bis-bipyridine, were used as alternate counterions in an aqueous surfactant solution of sodium dodecylbenzenesulfonate (SDBS) to investigate the dynamics of counterion interactions in an acoustic field. Sonoluminescence spectral studies showed that such counterions were able to replace sodium ions at the interface, even when the interface was rapidly oscillating under the acoustic field. Ultrasound induced nebulisation was then used to probe the interfacial profile of surfactant and bound counterions in a dynamic environment. At low bulk concentrations, the copper (II) bis-bipyridine cation was more effective at enhancing the loading of the dodecylbenzenesulfonate anion on the interface, due to its documented greater binding ability. However, at higher bulk concentrations, the movement of this cation is limited by its larger size and the smaller Cu 2+ cation is more effective in enhancing the loading of the dodecylbenzenesulfonate anion. The results show that under dynamic conditions, the surface concentrations are governed by mass transfer kinetics rather than equilibrium thermodynamics.

Rule based design of clay-swelling inhibitors

In oil and gas drilling operations, drilling fluids perform essential tasks such as lubricating the drill bit, providing hydrostatic pressure and removing drill cuttings. One important function of the drilling fluid is to stop compacted clay minerals, commonly encountered in drilling operations, from taking up water from the drilling fluids and consequently swelling. Such a scenario can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. With increasingly stringent environmental guidelines determining which swelling inhibitors are available for use in the oilfield as drilling fluid additives, there is a need to fully understand the mechanisms of clay hydration in order to design new swelling inhibitors which conform to evolving regulations. Using a range of computational techniques and analysis, combined with known experimental results, we have devised a set of “rule-based” design criteria for clay-swelling inhibitors. To achieve this, we have formulated a hydration energy parameter, which assesses the changes in energy during the step-wise progression from mono- to bi- to trilayers of water in the clay sheet galleries. This parameter can be used to rationalise and predict the swelling profiles for clays containing both cationic and neutral clay swelling inhibitors. The rules we have devised are as follows: (i) Cationic inhibitors should be able to replace sodium ions in the interlayer. (ii) Cationic inhibitors should possess a water soluble, hydrophobic backbone. (iii) Cationic inhibitors should have primary di-amine or mono-quaternary amine functionality. (iv) Cationic inhibitors should have little alcohol functionality. (v) The hydrophobic backbone of the cationic inhibitor should be long enough to form a dense monolayer in the interlayer. (vi) For neutral inhibitors, the inhibitor should be a water soluble organic molecule of low molecular weight with well defined domains of relatively high hydrophobicity and small domains of hydrophobicity. Our “rule-based” criteria will facilitate the rational design of improved—and more environmentally acceptable—clay swelling inhibitors for oilfield drilling operations.

Effect of glass composition on silver-incorporation into aluminoborosilicate glasses through a staining process

To fabricate graded-index optical elements by silver staining, we investigated the behavior of ion incorporation in aluminoborosilicate glasses, in which the contents of Al2O3and Na2O were the same (in mol%). The amount of silver incorporated into the aluminoborosilicate glasses by the staining at 320 °C for 12 h was 5 to 10 times larger than that incorporated into the soda-lime silicate and borosilicate glasses. The diffusion depth of the incorporated silver ions was approximately 80 μm, which was also much deeper than that of the soda-lime silicate and borosilicate glasses. The coloration of the glasses was suppressed, particularly for the glass with the low content of Na2O. The concentration of the incorporated silver ions at the glass surface was 2 × 1021atom/cm3for the 37.5SiO2·25Al2O3·25Na2O·12.5B2O3glass, corresponding to the replacement of sodium ions (20%). The refractive indices near the stained surfaces increased by 0.04 to 0.06. These values were comparable with those of the soda-lime silicate and borosilicate glasses.

Competitive binding exchange between alkali metal ions (K+, Rb+, and Cs+) and Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2: a 23Na and 1H NMR study

A comparative study of the competitive cation exchange between the alkali metal ions K+, Rb+, and Cs+ and the Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2 was performed in aqueous solution by a combined use of the 23Na and 1H NMR spectroscopy. The titration data confirm the different binding affinities of these ions for the G-quadruplex and, in particular, major differences in the behavior of Cs+ as compared to the other ions were found. Accordingly, Cs+ competes with Na+ only for the binding sites at the quadruplex surface (primarily phosphate groups), while K+ and Rb+ are also able to replace sodium ions located inside the quadruplex. Furthermore, the 1H NMR results relative to the CsCl titration evidence a close approach of Cs+ ions to the phosphate groups in the narrow groove of [d(G4T4G4)]2. Based on a three-site exchange model, the 23Na NMR relaxation data lead to an estimate of the relative binding affinity of Cs+ versus Na+ for the quadruplex surface of 0.5 at 298 K. Comparing this value to those reported in the literature for the surface of the G-quadruplex formed by 5'-guanosinemonophosphate and for the surface of double-helical DNA suggests that topology factors may have an important influence on the cation affinity for the phosphate groups on DNA.

The Involvement of Calcium Transport Systems of the Plasma Membrane in Calcium Exchange in Neurons of the Carassius gibelio Cerebellum

We studied the role of Na+/Ca2+ exchanger (NCX) and Ca2+-ATPase of the plasma membrane (РМСА), known to be the most important intracellular systems controlling calcium exchange in cerebellar neurons of a fish species tolerant to hypoxia, Carassius gibelio. In our experiments, we used the corresponding blockers of these transport systems, ions of lithium and lanthanum. The intracellular Ca2+ concentration ([Ca2+] і ) was measured using a calcium-sensitive dye, Fura-2AM, and a microfluorescence technique. We found that neurons of the Carassius cerebellum possess an effective system of cleaning of the cytoplasm from excessive Ca2+, which is provided by both NCX and РМСА functioning in the plasma membrane. Under conditions of the blockade of functioning of РМСА using lanthanum, the basal Ca2+ level in the cells increased, on average, by 31.4% with respect to the control, independently of the duration of test depolarizations. After switching off of the NCX functioning by the replacement of sodium ions in the extracellular solution by lithium ions, the Ca2+ level in the cell increased by 36.6% with respect to the control (also independently of the duration of depolarization). The obtained data indicate that the functioning of РМСА and NCX in Carassius cerebellar neurons significantly influences the intracellular calcium exchange providing the maintenance of an adequate basal Ca2+ level in these neurons.

Involvement of carrier-mediated transport system in uptake of tetrodotoxin into liver tissue slices of puffer fish Takifugu rubripes

Although puffer fish contain tetrodotoxin (TTX) at a high concentration mainly in liver, the underlying mechanism remains to be elucidated. In the present study, uptake of TTX into the liver tissue slices of puffer fish Takifugu rubripes was investigated by in vitro incubation experiment. When T. rubripes liver slices were incubated with 0–2000 μM TTX at 20 °C for 60 min, the uptake rates exhibited non-linearity, suggesting that the TTX uptake into T. rubripes liver is carrier-mediated. The TTX uptake was composed of a saturable component ( V max 47.7±5.9 pmol/min/mg protein and K m 249±47 μM) and a non-saturable component ( P dif 0.0335±0.0041 μL/min/mg protein). The uptake of TTX was significantly decreased to 0.4 and 0.6 fold by the incubation at 5 °C and the replacement of sodium-ion by choline in the buffer, respectively, while it was not affected by the presence of 1 mM l-carnitine, p-aminohippurate, taurocholate or tetraethylammonium. The TTX uptake by black scraper Thamnaconus modestus liver slices was much lower than that of T. rubripes and independent of the incubation temperature, unlike T. rubripes. These results reveal the involvement of carrier-mediated transport system in the TTX uptake by puffer fish T. rubripes liver slices.

Reaction of layered sodium disilicate SKS-6 with calcium chloride solution as revealed by solid state NMR spectroscopy: Exploring the calcium ion extracting mechanism of SKS-6

Solid-state 1H, 29Si NMR and 23Na MQMAS NMR spectroscopy combined with X-ray powder diffraction (XRD) technique was used to study the reaction between layered sodium disilicate SKS-6 and calcium chloride solution with different concentrations. Based on the experimental results the calcium ion extracting mechanism of SKS-6 was demonstrated to be via ion replacement, during which calcium ions replace sodium ions and combine with the non-bridging oxygen in SKS-6 for charge compensation, and simultaneously sodium ions leave the interlayer. This ion-replacement process was greatly influenced by the substitution of sodium ions by protons as well as the calcium ions concentration. Increasing calcium ions concentration favors the replacement of sodium ions by calcium ions, but prevents sodium ions from being substituted by protons.

Assessment of the stability of a dispersive soil treated by alum

Dispersive soils have been responsible for failures in several geotechnical and geoenvironmental projects. Chemical treatments have been used to overcome deficiencies in the dispersive performance of these types of soils. Alum (aluminum sulfate {Al 2(SO 4) 3·18H 2O}) is commonly used for the treatment of these types of soils. The interaction of soil–additives during the treatment process is a physico-chemical phenomenon. In this paper, the fundamental aspects of interaction between dispersive soil and alum are examined and evaluated. Bentonite samples were laboratory dispersed with the use of different concentrations of sodium sulfate (Na 2SO 4). Alum was then used to control their dispersivity performance. A set of physico-chemical experiments including Atterberg limits, permeability, consolidation, double hydrometer, ion exchange, and pH measurement were performed to investigate the fundamental mechanism of soil–alum interaction. XRD and SEM testing were performed to support the findings. Double hydrometer testing indicates that the application of 1.5% aluminum sulfate caused a noticeable decrease in dispersivity potential. The results obtained indicate that the addition of alum causes a decrease in the pH level of dispersive bentonite. In this process, a distinguishable change in the engineering properties of soil occurred, including a reduction in liquid limit and an increase in hydraulic conductivity. In fact, the replacement of sodium ions by aluminum ions in the double layer of the clay particles resulted in a decrease in the thickness of the particles' double layers. It is concluded that two different phenomena were responsible for overcoming soil dispersivity: ion exchange and pH effects.

Pulsed cathodoluminescence of two-alkali sodium potassium silicate glasses

Alkali silicate glasses of variable composition 22xNa2O · 22(1−x)K2O · 3CaO · 75SiO2 with equimolecular replacement of sodium ions by potassium ions are investigated using pulsed cathodoluminescence. It is revealed that localized electronic states interact with vibrations of two types, namely, polarization vibrations of the silicon-oxygen network with the frequency v0 = 820 cm−1 and bending vibrations of the modifier sublattice. At low concentrations of one of the alkali components (x < 0.1), bending vibrations are observed at two frequencies. These frequencies coincide with those of the corresponding vibrations in one-alkali systems containing Na (530 cm−1) and K (520 cm−1). At higher concentrations (x in the range ∼0.14–0.86), there occur bending vibrations of the cationic sublattice with a frequency of 420 cm−1. This can be interpreted as a luminescence analog of two-alkali (mixed-alkali) effect.

Permeability of human jejunal segments to gonyautoxins measured by the Ussing chamber technique

The aim of this work was to study the mechanisms involved in intestinal permeability of gonyautoxins. For this purpose, the influence on transmucosal resistance of gonyautoxins and their permeability was investigated in excised human jejunal segments. To evaluate these events, the isolated mucosa was mounted in Ussing chambers for electrophysiological characterization. The organic gonyautoxin cations were applied to the mucosal side and samples collected on the serosal side. The permeability of gonyautoxins measured at 37 °C was 4.3-fold greater than at 4 °C, indicative of high cation selective transcellular permeability. In order to characterize the permeability of gonyautoxins, the effects of choline, ouabain, phlorizin and fluorescein were studied. The inhibition by these compounds was expressed as percent inhibition of the maximal flux of gonyautoxins at 120 min. Replacement of sodium ion by choline, showed the highest inhibition (85.5% from control). Ouabain, fluorescein and phlorizin inhibit the gonyautoxins flux by 53.9, 41.0 and 9.64%, respectively. The inhibition of gonyautoxins’ permeability produced by ouabain and phlorizin go in parallel with an increase in the transmucosal electrical resistance (TER). This study shows that permeability of gonyautoxin cations occurred predominantly by the transcellular pathway (76%) when toxins were applied in the mucosal–serosal direction. The paracellular pathway of gonyautoxins was 24% of total permeability when compared with [ 3H] mannitol permeability. These findings suggests that permeability of gonyautoxins depends on temperature and processes involving sodium ion. Replacing sodium ions by choline ions showed a marked effect on TER.