Effect Of Cation Type Research Articles

Effect of Cation Types on the Steel Corrosion Inhibition Behavior of Calcined Layered Double Hydroxides in Saturated Calcium Hydroxide Solution

Effect of Cation Types on the Steel Corrosion Inhibition Behavior of Calcined Layered Double Hydroxides in Saturated Calcium Hydroxide Solution

Defect equilibrium and charge transport in R0.25Sr0.75FeO3−δ (R = La, Nd, Y, Ho): The effect of cation type

The perovskite-type oxides of R0.25Sr0.75FeO3−δ series for R = La, Nd, Y, Ho were subjected to X-ray and electron diffraction studies, thermogravimetric and dilatometric measurements. Coulometric titration and four-probe DC techniques were used to obtain data on oxygen content and electrical conductivity of the oxides in the range of oxygen partial pressure from 10−19 to 0.5 atm at 750–950 °C. A decrease in the size of R-cation in R0.25Sr0.75FeO3−δ was found to result in a decrease in the oxygen content in the oxides, thermal expansion, and electrical conductivity. In case of Y and Ho, an extra factor, in addition to the cation radius, affecting the oxide properties, is argued to be the limited oxygen coordination, which promotes local ordering in the respective oxides. This statement was confirmed by electron diffraction study, which detected incommensurate diffuse scattering as the evidence of partial local ordering of cations in the A sublattice in combination with the ordering of oxygen vacancies. This partial local ordering affects strongly functional properties of Y and Ho containing oxides. In particular, oxygen-ion conductivity at 950 °C decreases from 0.328 ± 0.005 to 0.055 ± 0.003 S/cm in response to the substitution of La in R0.25Sr0.75FeO3−δ by Y.

Effect of cation type on corrosion of steel treated by DNA corrosion inhibitor in simulated concrete pore solution

The purpose of this study is to evaluate the influence of cation types on the rust resistance performance of new nucleic acid corrosion inhibitors in simulated concrete pore solution. Four common chlorinated ice salts (sodium chloride (NaCl), potassium choride (KCl), calcium chloride (CaCl2) and magnesium chloride (MgCl2)) were selected to study the corrosion behaviour of chloride ions by linear polarisation resistance method, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results show that the cationic type will affect the thickness of the passivated film on the steel surface and the compactness of the passivated film formed by iron oxide and nucleic acid rust inhibitor. The type of cations affects the critical chloride concentration of nucleic acid inhibitor, following Na+ ≈ K+ > Ca2+ > Mg2+.

Spark plasma sintering of multi-cation doped (Yb, Sm) α/β-SiAlON ceramic tool materials: Effects of cation type, composition, and sintering temperature

The multi-cation doped α/β-SiAlON composite ceramics tool materials were prepared via spark plasma sintering. The effects of cation type (Yb, Sm, Yb/Sm), composition, and sintering temperature on densification behavior, phase formation, microstructural evolution, and mechanical properties of α/β-SiAlON were studied. Results showed that the addition of Sm2O3 in Yb/Sm-SiAlON could decline the shrinkage temperature and accelerate the densification process due to the increased liquid phase volume and decreased viscosity. The Sm2O3 played the role of both sintering additives and stabilizing cation of α-SiAlON, which could promote the formation of α-SiAlON and the elongation of β-SiAlON, thus acquired refined α grains and large aspect ratio of β grains. The SPS-sintered multi-cation doped Yb/Sm-SiAlON with 2 wt% additional Sm2O3 possessed excellent comprehensive mechanical properties (3.40 g/cm3, 18.53 ± 0.18 GPa, and 6.13 ± 0.23 MPa m1/2).

Prediction of Sulfate Attack Products in Portland-Limestone Cements: The Effect of Cation Type and Concentration

Portland-limestone cement materials are susceptible to sulfate attack at low temperature and high humidity, because such conditions facilitate the formation of thaumasite, detriment to the structural integrity of calcium silicate hydrates (C─S─H). In this work, the effect of the cation associated with sulfates, concentration of sulfate solution, and limestone content in cement, were thermodynamically simulated. MgSO4 solution is of higher risk, degrading extensively the structural integrity of C─S─H. Although this phase is partially preserved under the effect of Na2SO4 and K2SO4 solutions, extensive expansion and thaumasite formation occur. The sulfate content of the corrosive solution and the limestone content in cement are the factors mostly intensifying the attack caused by MgSO4 and Na2SO4/K2SO4 solutions, respectively.

Adsorption and separation of the C3 hydrocarbons on cationic FER zeolites: Effect of dual sites existence

Abstract Adsorption and co-adsorption of propane and propene were investigated by combination of calorimetric-volumetric measurements with breakthrough experiments on alkali metal exchanged (Li, Na-, K-) FER zeolites with different Si/Al ratio. Effect of cation type and their concentration in the zeolite on adsorption selectivity was evaluated and discussed. Based on determined adsorption heats at zero coverage limit, the bridged complexes of propene were confirmed only in the case of K-FER zeolites. Presence of bridged complexes between two nearby K+ cations in dual cationic sites, described in details previously (Rubes et al. J. Phys. Chem. C 122 (2018) 6128), results in significant increase in adsorption selectivity while adsorption capacity of the zeolite is not influenced and is comparable with other M-FER zeolites. On the other hand, Na-FER zeolites exhibited the lowest propene/propane selectivity (at least six-times lower than K-FER-8.6 zeolite).

Influence of salt-forming anions on the geotechnical properties of a soil stabilised with hydraulic binders: effect of cation type

A treatment with hydraulic binders confers to soils enhanced physical and mechanical characteristics that allows their integration in a road section. To gain acceptance of this technique, there is a clear requirement of studies that provide information on success and failures. The aim of this study was to investigate the influence of the salts (i.e. anions and cations) which are present in the soil, on the physical and the mechanical properties of a stabilised soil. Four anions (sulphate, chloride, nitrate, phosphate), associated with sodium or potassium, were added to one soil, using different chemical and concentrations combinations, before treatment. Tests in accelerated curing conditions were used because they are the first realised by the earthworks companies before they undertake further advanced study. The influence of the cationic counter ion and/or salt was also assessed, contrary to the usual recommendations (technical guides) that focused on the anions. The synergistic effects of anions and cations were investigated. For the considered soil, the chloride, nitrate or phosphate ions were less disruptive (important losses of strength or/and volumetric swelling) when associated with sodium than with potassium, while a reverse effect was noticed for sulphate ions. The simultaneous presence of sodium and potassium salts, for each type of anions, except nitrate, induced a significant swelling (up to 24%) and a loss of strength (down to - 75%). Considering stabilisation disturbances, sulphate salts appeared as the most disruptive, the significant swellings associated with ettringite formation causing structural damages. Some technical guides attributed the unsuitability for a soil to a treatment formulation to the presence of some anionic species in soils. This study demonstrated that the unsuitability has to be attributed to a salt, i.e. to the specific combinations of anion and cation. The tests that use simultaneously different salts were innovative and increase the reliability of the usual standard tests. That's why it seems important to reconsider the treatment study methodology used by the companies.

Composites of various cation exchanged forms of mesoporous zeolite A with polypyrrole-thermal, spectroscopic and gas sensing studies

Composites of polypyrrole with various cation exchanged forms of Zeolite A were successfully synthesized via chemical oxidative polymerization of Pyrrole (Py) in presence of a dispersion of A-zeolite (powder) in deionized water using anhydrous FeCl3 as an oxidant. The composites were characterized spectroscopically by Fourier Transform-Infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscopic (SEM) and Energy dispersive X-ray analysis (EDXA) for their nature, morphology and elemental analysis. Thermo-gravimetric analysis (TGA) was carried out for the thermal stability of the composites. Gas sensing studies were carried out for the carbon monoxide gas at the concentrations ranging from 5 ppm to 1000 ppm. The effects of cation type, zeolite content and CO concentration on the response of the composites were also investigated. The sensitivity of synthesized composites was found to obey the following order: Na-A/PPy > H-A/PPy > Fe-A/PPy > Cu-A/PPy > PPy depending upon the ionic radius of the cation present in the zeolite-polymer composites and the electronegativity. The response of the Na-A/PPy composite increases from 19.36% to 40.00% as the zeolite content was increased from 10% to 60% (w/w%). This increase in the sensitivity by increasing the zeolite content is due to the increase in the surface area of the composite.

Fabrication of polyaniline/zeolite composites and their response towards nitrogen dioxide

A composite of Polyaniline with zeolite erionite was synthesized by chemical oxidative polymerization method. The effect of cation type, cyclic interval, NO2 concentration over time, zeolite content on the response of polyanline and polyaniline/zeolite erionite composites towards NO2 was studied. Na-form shows largest response towards NO2 because of small electronegativity. The effect of cyclic interval on the response of the composite was studied and it was found that with increasing no. of cyclic intervals the response decreases. The response of the nanocomposite on exposing to NO2 first increases and then attains a constant value after some time.With increase in zeolite content; the response goes on increasing and attains a steady state beyond 50% zeolite content. The composites were characterized by FTIR, SEM and XRD techniques.

Deep extractive desulfurization of dibenzothiophene with imidazolium or pyridinium-based ionic liquids

Four nitrate-based ionic liquids (ILs), i.e. 1-Butyl-3-methylimdazolium nitrate ([Bmim][NO3]), 1-Octyl-3-methylimdazolium nitrate ([Omim][NO3]), 1-Butylpyridinium nitrate ([BPy][NO3]), and 1-Octylpyridinium nitrate ([OPy][NO3]) were synthesized and used as extractant for the removal of dibenzothiophene (DBT) from the model oil. The effects of cation type, cation's alkyl chain length, extraction time, temperature, and IL/model oil volume ratio on the DBT removal were investigated. The ILs demonstrated high extraction performance with this order: [Omim][NO3]>[OPy][NO3] ≈ [Bmim][NO3]>([BPy][NO3]. The results suggested that [Omim][NO3] could be utilized as an appropriate solvent for the extractive desulfurization of fuel oil. It could reduce 94.8% of sulfur content in model oil from 500 to 26ppm at 25°C and IL/model oil volume ratio of 1:1 in a single-stage extraction. [Omim][NO3] could be reused six times without an impressive decrease in its activity.

The effect of cation type, ionic strength and temperature on the complexation between polyallylammonium cation and polystyrenesulfonate anion

The reaction between polyallylammonium cation and polystyrenesulfonate anion was investigated in alkali-metal chloride (MCl, M=Li, Na, K, Rb, Cs), sodium perchlorate and tetraethylammonium chloride solutions by means of microcalorimetry, potentiometry, DLS and spectrophotometry. The influence of ionic strength, temperature and addition order on the course of interpolyelectrolyte neutralisation was examined. At lower molar ratios of positively to negatively charged monomers and at 25°C primary polyelectrolyte complexes were formed. Close to equivalence their flocculation occurred. The complexation was predominantly entropically driven, however a correlation between obtained reaction and cation hydration enthalpies was noticed. The composition of the precipitates at equimolar monomer ratio in chloride salt solutions did not significantly depend on the addition order up to 1.0moldm−3 salt concentration. In contrast, the ratio of oppositely charged monomers in precipitates prepared in NaClO4 (c/moldm−3≥0.5) was affected by the addition order in a wide temperature range. The increase in electrolyte concentration and the decrease in temperature led to more pronounced asymmetric neutralisation. The equilibrium establishment in NaClO4(aq) proceeded extremely slowly. Even at high perchlorate concentrations the final reaction product was virtually insoluble polysalt.

Impact of cation type and concentration in injected brine on oil recovery in sandstone reservoirs

Low salinity waterflood has a high potential to improve oil recovery. However, the optimum water chemistry for waterflooding is still not well known, and the dominant mechanisms are debated. In the present work, the effect of cation type and concentration in the injected water on the oil recovery to identify the optimum water salinity and composition was studied by performing coreflood experiments. In addition, zeta potentials at oil/brine and rock/brine interfaces were measured to examine the impact of brine composition on electrical double layer expansion and investigate if it is one of the dominate mechanisms. Furthermore, ionic exchange tests were conducted to improve the understanding of the rock/brines interactions. Berea sandstone cores were used for waterflooding and ion exchange experiments; all coreflood experiments were performed at high-pressure/high-temperature (HP/HT) conditions. Different concentrations of NaCl, CaCl2, and MgCl2 solutions were tested with two crude oils of different compositions and properties. Ion concentrations in the core effluent fluids were analyzed for both waterflooding and ionic exchange tests. The zeta potential was measured for solutions of oil/brine, and solid/brine; the solids were Berea sandstone, quartz, feldspar, and four types of clays. This work contributes to the understandings of the impacts of double layer expansion on oil recovery during waterflooding. Zeta potential results showed that Na+ changes the electrical charge at both oil/brine and rock/brine interfaces to highly negative, which results in higher repulsive forces between the two interfaces, and hence wettability alteration. Moreover, waterflood experiments with NaCl solutions improved oil recovery significantly compared to CaCl2 and MgCl2. These results showed that there seems to be a correlation between zeta-potential and oil recovery which implies that double-layer expansion could be a primary mechanism of oil recovery by low salinity waterflood. This study demonstrates that cation type has a significant impact on oil recovery, and it could be more dominant than the effect of total salinity of the injected brines. These findings can help in screening the brines that have higher potentials for oil recovery improvement.

Effect of cation type, alkyl chain length, adsorbate size on adsorption kinetics and isotherms of bromide ionic liquids from aqueous solutions onto microporous fabric and granulated activated carbons

The adsorption from aqueous solution of imidazolium, pyrrolidinium and pyridinium based bromide ionic liquids (ILs) having different alkyl chain lengths was investigated on two types of microporous activated carbons: a fabric and a granulated one, well characterized in terms of surface chemistry by “Boehm” titrations and pH of point of zero charge measurements and of porosity by N2 adsorption at 77 K and CO2 adsorption at 273 K. The influence of cation type, alkyl chain length and adsorbate size on the adsorption properties was analyzed by studying kinetics and isotherms of eight different ILs using conductivity measurements. Equilibrium studies were carried out at different temperatures in the range [25–55 °C]. The incorporation of ILs on the AC porosity was studied by N2 adsorption–desorption measurements at 77 K. The experimental adsorption isotherms data showed a good correlation with the Langmuir model. Thermodynamic studies indicated that the adsorption of ILs onto activated carbons was an exothermic process, and that the removal efficiency increased with increase in alkyl chain length, due to the increase in hydrophobicity of long chain ILs cations determined with the evolution of the calculated octanol–water constant (Kow). The negative values of free energies indicated that adsorption of ILs with long chain lengths having hydrophobic cations was more spontaneous at the investigated temperatures.

Correction to Adsorption and Separation of CO2 on KFI Zeolites: Effect of Cation Type and Si/Al Ratio on Equilibrium and Kinetic Properties

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Adsorption and Separation of CO2 on KFI Zeolites: Effect of Cation Type and Si/Al Ratio on Equilibrium and Kinetic PropertiesTom Remy, Sunil A. Peter, Leen Van Tendeloo, Stijn Van der Perre, Yannick Lorgouilloux, Christine E. A. Kirschhock, Johan A. Martens, Yanliang Xiong, Gino V. Baron, and Joeri F. M. Denayer*Cite this: Langmuir 2014, 30, 10, 2968Publication Date (Web):March 5, 2014Publication History Published online5 March 2014Published inissue 18 March 2014https://doi.org/10.1021/la500366nCopyright © 2014 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views512Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (104 KB) Get e-Alerts Get e-Alerts

Experimental Observation of Surface Charge Inversion in a Biological Nanopore in Presence of Monovalent and Multivalent Cations

The electric double layer formed at the pore surface produces the exclusion of coions and the accumulation of counterions. A particularly captivating situation occurs when interfacial charges attract counterions in excess of their own nominal charge, thus leading to an effective charge inversion of the system. This phenomenon has been reported in such diverse systems like lipid vesicles, colloids, Langmuir monolayers, membranes, flexible polyelectrolytes and other synthetic nanodevices that are in contact with an aqueous solution containing multivalent ions. Here, we report experimental evidence of charge inversion in the bacterial channel OmpF of E. coli, not only in presence of multivalent cations but also in presence of monovalent ones. We perform reversal potential experiments in different conditions of pH and salt concentration to analyze both the effect of cation type and size in the selectivity changes.

Molecular Simulation of Hydrogen Storage in Ion-Exchanged X Zeolites

Grand Canonical Monte Carlo (GCMC) method was employed to simulate the adsorption properties of molecular hydrogen on ion-exchanged X zeolites at 100–293 K and pressures up to 10 MPa in this paper. The effect of cation type, temperature, and pressure on hydrogen adsorption capacity, heat of adsorption, adsorption sites, and adsorption potential energy of ion-exchanged X zeolites was analyzed. The results indicate that the hydrogen adsorption capacity increases with the decrease in temperatures and the increase in pressures and decreases in the order ofKX<LiX<CaX. The isosteric heat of adsorption for all the three zeolites decreases appreciably with the increase in hydrogen adsorption capacity. The hydrogen adsorption sites in the three zeolites were determined by the simulated distribution of hydrogen adsorption energy and the factors that influence their variations were discussed. Adsorption temperature has an important effect on the distribution of hydrogen molecules in zeolite pores.

Effect of Cation Type and Concentration of Nitrates on Neurological Disorders during Experimental Cerebral Ischemia

Experiments were performed on the model of ischemic stroke due to bilateral occlusion of the carotid arteries. Nitrates had various effects on the dynamics of neurological disorders and mortality rate of Wistar rats, which depended on the cation type and concentration.

Restructuring of a Peat in Interaction with Multivalent Cations: Effect of Cation Type and Aging Time

It is assumed to be common knowledge that multivalent cations cross-link soil organic matter (SOM) molecules via cation bridges (CaB). The concept has not been explicitly demonstrated in solid SOM by targeted experiments, yet. Therefore, the requirements for and characteristics of CaB remain unidentified. In this study, a combined experimental and molecular modeling approach was adopted to investigate the interaction of cations on a peat OM from physicochemical perspective. Before treatment with salt solutions of Al3+, Ca2+ or Na+, respectively, the original exchangeable cations were removed using cation exchange resin. Cation treatment was conducted at two different values of pH prior to adjusting pH to 4.1. Cation sorption is slower (>>2 h) than deprotonation of functional groups (<2 h) and was described by a Langmuir model. The maximum uptake increased with pH of cation addition and decreased with increasing cation valency. Sorption coefficients were similar for all cations and at both pH. This contradicts the general expectations for electrostatic interactions, suggesting that not only the interaction chemistry but also spatial distribution of functional groups in OM determines binding of cations in this peat. The reaction of contact angle, matrix rigidity due to water molecule bridges (WaMB) and molecular mobility of water (NMR analysis) suggested that cross-linking via CaB has low relevance in this peat. This unexpected finding is probably due to the low cation exchange capacity, resulting in low abundance of charged functionalities. Molecular modeling demonstrates that large average distances between functionalities (∼3 nm in this peat) cannot be bridged by CaB-WaMB associations. However, aging strongly increased matrix rigidity, suggesting successive increase of WaMB size to connect functionalities and thus increasing degree of cross-linking by CaB-WaMB associations. Results thus demonstrated that the physicochemical structure of OM is decisive for CaB and aging-induced structural reorganisation can enhance cross-link formation.

Sensitive and Selective Responses of Poly(Para-Phenylene Vinylene)/Zeolite Y-Based Sensors Toward Ketone Vapors

Poly (p-phenylene vinylene) doped with H2SO4 is mixed into zeolite Y matriced to improve the electrical conductivity responses toward ketone vapors. The effect of cation type, cation concentration, and ketone vapor type on the electrical conductivity response toward ketone vapors of dPPV_zeolite Y composites is investigated. The sensitivities of the composites increase linearly with increasing surface area and decreasing cationic radius of the cation in zeolite Y. The highest sensitivity is obtained with the dPPV_[90] Y when exposed to acetone, whereas in MIBK shows the lowest sensitivity The interactions between the ketone molecules and the composites are investigated though the FTIR.

Adsorption and Separation of CO2on KFI Zeolites: Effect of Cation Type and Si/Al Ratio on Equilibrium and Kinetic Properties

Selective separation of CO2 is becoming one of the key technologies in the (petro-) chemical industry. This study focuses on the adsorption and separation of CO2 from CH4 on a new low-silica (LS) type of the eight-membered ring KFI zeolite. A series of alkali (Li, Na, K) and alkaline-earth (Mg, Ca, Sr) exchanged samples of the new LS KFI were synthesized and characterized. LS Li-KFI showed the largest pore volume, whereas LS Na-KFI and LS K-KFI were inaccessible for Argon at 87 K. Adsorption of CO2 at 303 K demonstrated the dominant quadrupolar interaction on alkali-exchanged LS KFI samples. LS Li-KFI showed the largest capacities upon high pressure isotherm measurements of CO2 (4.8 mmol/g), CH4 (2.6 mmol/g), and N2 (2.2 mmol/g) up to 40 bar at 303 K. The performance of the new LS KFI was compared to a KFI sample (ZK-5) with a higher Si/Al ratio. Isotherm measurements and dynamic breakthrough experiments demonstrated that ZK-5 samples show larger working capacities for CO2/CH4 separations at low pressure. Li-ZK-5 and Na-ZK-5 show the highest capacities and high selectivities (similar to benchmark 13X).