Ternary Exchange Research Articles

Preparation and performance of sulfonated poly(ether ether ketone) membranes enhanced with ammonium ionic liquid and graphene oxide

The exploration of proton exchange membranes with excellent performance has always been under focus for improving the performance of proton exchange membrane fuel cells. In this study, novel ternary composite proton exchange membranes based on sulfonated poly(ether ether ketone) (SPEEK), triethylamine phosphate (TEAP) as the ammonium ionic liquid (AIL), and graphene oxide (GO) were prepared. The prepared membranes were characterized for their physical, physico-chemical, structural, morphological, thermal, mechanical, and electrical characteristics. The thermal stability of the SPEEK membrane was improved by the addition of GO and TEAP. GO was inserted into the composite membrane to form proton transfer channels. The amine ions in AIL formed acid–base pairs with the sulfonic acid group, whereas the oxygen-containing group on GO formed hydrogen bonds with the phosphate group. These groups interacted with each other to form a honeycomb-like structure, which anchored the AIL in the membrane and reduced its loss, providing additional sites for proton transport at higher temperatures. The proton conductivity of the SPEEK/AIL/GO-2 membrane reached 17.345 mS/cm at 120°C, which was 2.09 times higher than that of the pristine SPEEK membrane. This study provides the possibility for better preparation of proton exchange membranes used for high-temperature proton exchange membrane fuel cells.

Novel sulfonated polystyrene-block-poly (ethylene-ran- butylene)-block-poly styrene / graphene oxide / ammonium ionic liquid based ternary composite: An efficient ion-exchange solid electrolyte

ABSTRACT Novel ternary proton exchange membranes composed of sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (sPSEBPS), graphene oxide (GO) and ammonium ionic liquid (AIL) were prepared by a facile solution casting technique. The incorporation of GO and AIL into the sPSEBPS polymer matrix enhances the thermal stability and the ionic conductivity of the composites. The ion-exchange capacity of the membranes was found in the range between 0.281 and 1.248 meq. g−1. The sPSEBPS/GO/AIL-20 composite membrane showed a proton conductivity of 0.0353 S. cm−1 at 30 °C. The outcome of the results projected that the prepared polymer composite membranes are viable candidates for fuel cell applications.

A Conversational Perspective of Binary and Ternary Exchanges in the Interactional Discourse

A Conversational Perspective of Binary and Ternary Exchanges in the Interactional Discourse

Estimation of Thermodynamic Equilibrium Constant for Binary and Ternary Cation Exchange Reactions Using Rothmund–Kornfeld and Regular Solution Models in Some Soils and Soil Clays

ABSTRACT Rothmund–Kornfeld selectivity coefficient (KRK) and regular solution model are rarely used to describe soil exchange data but it seems to be able to satisfactorily predict the true thermodynamic equilibrium constant (Kex). We tested the ability of Rothmund–Kornfeld and regular solution models to predict Kex in binary (K–NH4, Ca–Mg, and K–Ca) and ternary (Na–Ca–Mg) cation exchange systems in clays and soils with different dominant mineralogies. Applying the Rothmud–Kornfeld model to the exchange data indicated the preference of K over Ca and NH4, and Ca over Mg in binary, and Ca over Mg in ternary exchange systems. Similar results were obtained on the preference of cations by different exchangers when the regular solution model was applied to describe the exchange data. Despite the different assumptions of Rothmund–Kornfeld and regular solution models to approximate the activity coefficient of the ions on the exchange phase, similarity between the value of selectivity coefficients obtained by these two models was observed in homovalent cation exchange reactions. Also, a close agreement was observed between the value of selectivity coefficients obtained by these two models and Kex. However, in heterovalent cation exchange reactions, Rothmund–Kornfeld and regular solution models did not provide accurate estimation of the Kex. But these models can correctly indicate the overall preference of one ion to another as Kex. The results suggested Rothmund–Kornfeld and regular solution models can be applied satisfactorily in clay and soil systems as a rapid method to estimate Kex, especially in homovalent exchange reactions. Abbreviation KRK : Rothmund–Kornfeld selectivity coefficient; Kex: True thermodynamic equilibrium constant; ƒ: Exchange-phase activity coefficients; NP: Thermodynamic non-preference; E: Equivalent fractions of ion in exchange phases; Ẽ: Equivalent fractions of ion in solution phases; KRS: Regular solution selectivity coefficient; Kv: Vanselow selectivity coefficient; ∆Gex: Gibbs free energy change

Ternary proton exchange membranes with low‐cost raw materials: Solvent type influence on microstructure development, high ionic conductivity, and ionic liquid lixiviation protection

ABSTRACTA critical stage of solvent evaporation during membrane casting was identified as responsible for significant differences in performance of ternary membranes composed of PEEK with 73% of sulfonation degree. DemaTfO and MmtdemaDMF showed to be the best solvent for casting of membranes prepared through the present study, which is against the observations made through other different studies. Fractal structures are formed regardless of solvent polarity, and interlamellar spacing is found to be higher when DMF is used, which led to higher conductivity and IL leaching protection. Proton relaxometry showed that only the membranes made with DMF and DMAc possess one single mobility domain. Transmission electron microscopy micrographs showed a higher damage in membranes with two different mobility domains and consequent phase separation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46012.

Adsorption of Propylene and Propane onto Mn+X (Mn+ = Cr3+ and/or Ni2+) Zeolites and Comparison between Binary and Ternary Exchanges

Mn+X zeolites (Mn+ = Ni2+ and/or Cr3+) were prepared and characterized by various techniques. The adsorption of propylene and propane onto these zeolites was investigated, and thermodynamic properties were discussed. The objective is to establish a comparison between the binary (introduction of Ni2+ or Cr3+ instead of Na+) and ternary (introduction of Ni2+ and Cr3+ instead of Na+) exchanges. To our knowledge, there is no work in this field, in spite of a growing interest in bimetallic zeolites. Isotherms of C3H6 and C3H8 were successfully modeled using the Toth equation. A change in KH, Henry’s law slope, confirms the strong and weak characters of the interactions with propylene and propane, respectively. CrNi(39)X has an intermediary behavior between Cr(39)X and Ni(40)X. It manifests specific interaction with C3H6 molecules through the deep implication of Cr3+ cations, at low coverage. With increasing adsorbate concentration, the contribution of Ni2+ occurs.

Effects of Magnesium on Cation Selectivity and Structural Stability in prominent Vertisols of Karnataka

A study was conducted to evaluate the effects of Mg on ternary (Na-Ca-Mg) exchange and intern structural stability in prominent Vertisols of TBP (Tungabhadra Project) and UKP (Upper Krishna Project) irrigation commands of Karnataka State, India. Surface soil samples representing typical Vertisols derived from granite-gneiss (Gangavati and Kavadimatti), limestone (Devapur and Islampur) and basalt (Kadliwad and Mannapur) were included in the study. These soils were subjected to equilibration with waters of varying sodium adsorption ratio (SAR-5,20,40,60,80 and 100 millimoles per liter1/2) with different Ca/Mg ratio (4:1,2:1,1:1,1:2and 1:4).Exchangeable Na increased as the Mg/Ca ratio increased from 1:4 to 4:1 indicating that Mg charged waters are more detrimental for structural integrity of the soils. Averaged from all SAR treatments, the Mg-Na systems had between 10.5 to 12.1% more exchangeable Na than did the Ca-Na systems. The Mg-induced increase in exchangeable Na was directly related to a preference by the soils for Ca over Mg, which makes Na more competitive against Mg than against Ca. The influence of Mg on soil structural stability was examined by measuring degree of dispersion, capillary raise and moisture diffusivity using Na-Ca-Mg solutions varying with Ca/Mg ratios and SAR values. In order to segregate the specific effect of Mg, separate binary systems (exclusive Ca-Mg solutions with varying concentrations without Na) were used to examine the degree of dispersion. The Mg-Na system developed considerably lower soil moisture diffusivity and higher degree of dispersion as well as capillarity than did the Ca-Na system when equilibrated with solutions having total electrolyte concentration 20 m mol liter-1. Dispersion and water transmission tests confirmed that the effect of Mg was greater than could be explained by the higher exchangeable Na alone in the Mg system or else Mg had a specific effect on clay dispersion. It was obviously proved that Mg does have the effect on clay dispersion in the binary system involving diminishing Ca concentration where Na was completelyexcluded. Our results suggest that exchangeable Mg is about 1/10th, 1/20th, and 1/30th as dispersive as Na in granite-gneiss, limestone and basalt derived soils, respectively.

Ternary Hybrid Proton Exchange Membranes Based on POSS

The sulfonated poly(ether ether ketone) (SPEEK)/bisphenol S diglycidyl ether (DEBS)/POSS ternary hybrids is designed and prepared to incorporate POSS into SPEEK to form a new cross-linked proton exchange membrane (PEM). Compared with the SPEEK, the ternary hybrids possesses lower water uptake (WU) and linear expansion (LE), but higher proton conductivity. The proton conductivity of SPEEK/DEBS/POSS can reach to 1.1×10-1 S/cm.

Acidity study of X zeolites modified by nickel and/or chromium cations in the case of binary and ternary exchanges

A series of Ni(x)-, Cr(x) and CrNi(x)-exchanged X zeolites (x being the ion-exchange degree) was prepared and characterised by nitrogen adsorption, XRD, DTA/TGA and pyridine adsorption–desorption followed by IR spectroscopy. The objective is mainly to estimate quantitatively the number, strength and nature of acid sites and their dependence on the type of cation and its exchange level. A comparison between the binary and ternary exchanges was also established. The crystallinity and micropore volume losses were more significant for Cr(x)X and CrNi(x)X. The concentration of Lewis acid sites decreases with increasing the exchange degree for Cr(x)X and Ni(x)X, while it increases up to 39% for CrNi(x)X. An increase of the concentration of Brønsted sites was obtained. The fact that both the Lewis and Brønsted acidities markedly decrease between 423 and 623K, proves that the available acid sites are overall weak. The pyridine desorption from the protonic sites is easier with CrNi(39)X than with Cr(39)X and Ni(40)X at 623K, indicating a decrease in the strength in the case of ternary exchange.

Ion exchange equilibrium between cation exchange membranes and aqueous solutions of K+/Na+, K+/Ca2+, and Na+/Ca2+

Equilibrium between synthetic ion exchangers and solutions of cations has been the subject of this investigation. Competitive ion exchange reactions were studied for two cation exchange membranes (CMX and CRP) involving K+, Na+, and Ca2+ ions. The ionic strength of the equilibrating solutions was maintained constant, but the molar fraction varied; all experiments were conduced with nitrate as nonexchanging anions at 25 °C. Adsorption isotherm for the three binaries systems: K+/Na+, K+/Ca2+, and Na+/Ca2+ were studied. The obtained results show that potassium was the most strongly sorbed and the selectivity order for CMX and CRP membranes is K+>Ca2+>Na+ at 0.1 M, under the experimental conditions. Selectivity coefficients \({\text{K}}_{{\text{K}}^{\text{ + }} }^{{\text{Na}}^{\text{ + }} } \), \({\text{K}}_{{\text{2}}\,{\text{Na}}^{\text{ + }} }^{{\text{Ca}}^{{\text{2 + }}} } \), and \({\text{K}}_{{\text{2}}\,{\text{K}}^{\text{ + }} }^{{\text{Ca}}^{{\text{2 + }}} } \) for the three binaries and for the two membranes were determined at an ionic strength of 0.1 M and at a constant temperature of 25 °C. We remark that all the selectivity coefficient values are quite different from the unit. Ternary equilibrium was taken for the Ca2+/K+/Na+ system. It was found that binary selectivity data could be successfully used to predict the ternary ion exchange equilibrium.

Effect of the binary and ternary exchanges on crystallinity and textural properties of X zeolites

The ionic exchange of the NaX zeolite by Cu 2+ and/or Zn 2+ cations is progressively driven while following the development of some of its characteristic: crystallinity by XR diffraction, profile of isotherms, RI criterion, isosteric adsorption heat and microporous volume using both the Dubinin–Radushkevich (DR) equation and the t-plot through the Lippens–de Boer method which also makes it possible to determine the external surface area. Results show that the cationic exchange process, in the case of Cu 2+ introduced at higher degree, is accompanied by crystalline degradation for Cu( x)X, in contrast to Zn 2+-exchanged zeolite X. This degradation occurs without significant presence of mesopores, because the RI criterion values were found to be much lower than 2.2. A comparison between the binary and ternary exchanges shows that the curves of CuZn( x)X are clearly below those of Zn( x)X and Cu( x)X, whatever the examined parameter. On the other hand, the curves relating to CuZn( x)X tend towards those of Cu( x)X. This would again confirm the sensitivity of the crystalline structure of CuZn( x)X with respect to the introduction of Cu 2+ cations. An original result is the distortion of the zeolitic framework of X zeolites at middle exchange degree, when Cu 2+ competes with another divalent cation, such as Zn 2+, for the occupancy of sites distributed within zeolitic cavities. In other words, the ternary exchange accentuates the crystalline degradation of X zeolites. An unexpected result also is the noncorrelation between crystal damage and the external surface area.

Evaluation of Soils for Use as Liner Materials: A Soil Chemistry Approach

Movement of NH(4)(+) below animal waste lagoons is generally a function of the whole-lagoon seepage rate, soil mineralogy, cations in the lagoon liquor, and selectivity for NH(4)(+) on the soil-exchange sites. Binary exchange reactions (Ca(2+)-K(+), Ca(2+)-NH(4)(+), and K(+)-NH(4)(+)) were conducted on two soils from the Great Plains and with combinations of these soils with bentonite or zeolite added. Binary exchanges were used to predict ternary exchanges Ca(2+)-K(+)-NH(4)(+) following the Rothmund-Kornfeld approach and Gaines-Thomas convention. Potassium and NH(4)(+) were preferred over Ca(2+), and K(+) was preferred over NH(4)(+) in all soils and soils with amendments. Generally, the addition of bentonite did not change cation selectivity over the native soils, whereas the addition of zeolite did. The Rothmund-Kornfeld approach worked well for predicting equivalent fractions of cations on the exchanger phase when only ternary-solution phase compositions were known. Actual swine- and cattle-lagoon solution compositions and the Rothmund-Kornfeld approach were used to project that native soils are predicted to retain 53 and 23%, respectively, of the downward-moving NH(4)(+) on their exchange sites. Additions of bentonite or zeolite to soils under swine lagoons may only slightly improve the equivalent fraction of NH(4)(+) on the exchange sites. Although additions of bentonite or zeolite may not help increase the NH(4)(+) selectivity of a liner material, increases in the overall cation exchange capacity (CEC) of a soil will ultimately decrease the amount of soil needed to adsorb downward-moving NH(4)(+).

A cation exchange model to describe Cs + sorption at high ionic strength in subsurface sediments at Hanford site, USA

A theoretical and experimental study of cation exchange in high ionic strength electrolytes was performed using pristine subsurface sediments from the U.S. Department of Energy Hanford site. These sediments are representative of the site contaminated sediments impacted by release of high level waste (HLW) solutions containing 137Cs + in NaNO 3 brine. The binary exchange behavior of Cs +–Na +, Cs +–K +, and Na +–K + was measured over a range in electrolyte concentration. Vanselow selectivity coefficients ( K v) that were calculated from the experimental data using Pitzer model ion activity corrections for aqueous species showed monotonic increases with increasing electrolyte concentrations. The influence of electrolyte concentration was greater on the exchange of Na +–Cs + than K +–Cs +, an observation consistent with the differences in ion hydration energy of the exchanging cations. A previously developed two-site ion exchange model [Geochimica et Cosmochimica Acta 66 (2002) 193] was modified to include solvent (water) activity changes in the exchanger phase through application of the Gibbs–Duhem equation. This water activity-corrected model well described the ionic strength effect on binary Cs + exchange, and was extended to the ternary exchange system of Cs +–Na +–K + on the pristine sediment. The model was also used to predict 137Cs + distribution between sediment and aqueous phase ( K d) beneath a leaked HLW tank in Hanfordd's S-SX tank using the analytical aqueous data from the field and the binary ion exchange coefficients for the pristine sediment. The K d predictions closely followed the trend in the field data and were improved by consideration of water activity effects that were considerable in certain regions of the vadose zone plume.

Experimental study and modelling of zinc and lead migration in sandy soils due to stormwater infiltration

Heavy metals emitted by road traffic are contaminants of roadside soils and can potentially migrate through the soils down to groundwater during runoff water infiltration. Stormwater management requires a better understanding of the mechanisms involved in the transport and particularly chemical interactions between heavy metals and the solid matrix. Experiments with open dynamic systems and modelling with a mixing-cells-in-series model have been performed to identify the main reactions which govern the migration of zinc and lead in sandy soils. Binary and ternary exchange experiments have been performed and a numerical modelling was proposed to describe zinc and lead mobility in column experiments.

Prediction of K-Ca-Mg ternary exchange from binary isotherms in volcanic soils using the Rothmund-Kornfeld approach

The Gaines-Thomas formulation of the Rothmund-Kornfeld equation was used to predict the K-Ca-Mg exchange in variable surface charge soils. Binary and ternary equilibria were carried out at 25°C and at constant ionic strength of 0.050 mol/L. The selectivity sequence K > Ca > Mg was observed in binary isotherms. The experimental ternary isotherms are well described from binary data. When experimental v. calculated equivalent fractions were plotted, slopes between 0.901 and 1.051, and correlations between 0.970 and 0.986, were obtained. The design used assures in volcanic soils that no, or minor, changes in surface charge, cation exchange capacity, and selectivity occur, but the predicted ternary values are restricted to the same binary experimental conditions employed.

A transport model with coupled ternary exchange and chemisorption retention for hydrazinium cations.

A numerical model was developed to describe the fate and transport of hydrazinium (N2H5+) and competing Ca2+ and H+ cations applied in acidic solutions to columns of Ca2+/H+-saturated sandy soil during steady saturated flow conditions. Instantaneous ternary H+-Ca2+-N2H5+ cation exchange using the Gaines-Thomas approach was combined with second-order, irreversible, kinetic chemisorption of exchange-phase N2H5+ ions as major retention mechanisms for N2H5+. Exchange-mediated chemisorption is assumed to occur as chemical binding of N2H5+ ions located on carboxyl-group exchange sites to nearby carbonyl groups, consequently decreasing the effective soil cation exchange capacity (CEC). Comparison of simulated and observed breakthrough curves (BTCs) for concentrations of N2H5+ and Ca2+ ions in column effluent was used in model evaluation. The cation transport model with cation exchange coupled with exchange-mediated chemisorption provided a valid first approximation for N2H5+ transport.

Ion Exchange of Divalent Cobalt and Iron with Na–Y Zeolite: Binary and Ternary Exchange Equilibria

Divalent cobalt and iron removal from aqueous solutions by batch ion exchange with a synthetic Na–Y zeolite has been studied under competitive and noncompetitive conditions. The binary Co/Na and Fe/Na ion-exchange equilibrium isotherms, constructed at 291±2 K and a total solution positive charge concentration of 0.1 eq dm−3, exhibited sigmoidal shapes that are attributed to an exchange site heterogeneity. The solution pH and the ratio of sorbate to sorbent are identified for which minimal imbibition of metal hydroxide and maintenance of zeolite structural integrity are ensured. An increase in Fe and Co concentration over the range 0.005–0.05 mol dm−3 lowered the removal efficiency but the external Fe was preferred to the indigenous sodium over the entire concentration range; there was a switch in preference from Co to Na at [Co] in excess of 0.034 mol dm−3. Exchange data for Cu2+/Na+ and Ni2+/Na+ binary systems are included for comparative purposes, and ion exchange affinity and Na–Y exchange capacity are discussed in terms of metal ion hydration and ion location. The effect of exchange temperature has been considered where the maximal Fe exchange was temperature independent while Co exchange was promoted with increasing temperature. A Co/Fe/Na–Y ternary exchange isotherm was constructed from 20 pairs of experimental points and is treated quantitatively in terms of ternary and pseudo-binary separation factors. The preference of the zeolite for exchange with iron over cobalt under noncompetitive conditions also extended to solutions containing both metals.

EQUILIBRIUM OF METALS WITH IMINODIACETIC RESIN IN BINARY AND TERNARY SYSTEMS

ABSTRACT Experiments of binary and ternary ion exchange equilibrium of heavy metals and sodium were carried out in a complexing iminodiacetic resin Lewatit TP 207. First, binary equilibrium data were obtained at different temperatures and ionic strength and fixed to models considering two different ion exchange stoichiometrics. For ternary equilibrium data, two distinct simple models were applied. One to be applied to systems showing very different selectivity for the metals (for instance, Cu2+/Co2+/Na+) and the other for systems with similar selectivity for the metals (such as Zn2+/Co2+/Na+). The ternary equilibrium data obtained is presented in this work and fitted using the two above mentioned models. These models allow us to obtain the equilibrium parameters for binary and ternary system to be used in the design of equipment using this iminodiacetic resin.

Film Model Approximation for Particle-Diffusion-Controlled Multicomponent Ion Exchange

A film-model approximation is developed to predict multicomponent ion exchange in spherical particles. Mass transfer is represented by pseudosteady-state diffusion through a stagnant film of thickness equal to one-fifth of the particle radius. An exact analytic solution is found for the case of homovalent exchange and an approximate solution for the case of heterovalent exchange. Results obtained from the exact solution of the Nernst-Planck model are compared to those obtained using the film-model approximation for the case of ternary exchange in infinite-batch and fixed-bed systems. The predictions based on the film-model approximation are in good agreement with the exact solution for both homovalent and heterovalent ion exchange, indicating that the film-model approximation can be used effectively in numerical simulations of complex ion-exchange systems.

Le système feldspathique ternaire Na-K-Rb: modélisation et expérimentation

It is possible to model the excess molar Gibbs free energy at any point of the ternary system albite-sanidine-rubidium feldspar from a knowledge of the three equilibria between hydrothermal chloride solutions and binary feldspars. The domain of immiscibility determined at 600 °C, 150 MPa by ternary exchange experiments corresponds to an excess energy larger than 3 kJ·mol −1. The composition of the fluid in equilibrium with feldspars is richer in Na than the one-phase feldspar or the mechanical mixture of two feldspars, except near the albite end member, and its K/Rb ratio is always similar to that of the solid. The experiments cannot explain the compositions of natural Rb feldspars which seem to correspond to a solvus. Some hypotheses are presented for future studies.