Ion-Exchange Properties of lon-Sieve-Type Manganese Oxides Prepared by Using Different Kinds of Introducing Ions

Abstract

Three ion-sieve-type manganese oxides, HMnO(Li), HMnO(Na), and HMnO(K), were prepared by acid treatments of Li⁺-, Na⁺-, and K⁺-introduced manganese oxides, respectively. Three oxides were obtained from γ-MnO² and the corresponding alkali metal hydroxides by heating at 600°C. The ion-exchange properties of the adsorbents were investigated by pH titration, K_d measurements, and the adsorption of metal ions from seawater. The selectivity sequences of alkali metal ions were Na⁺ < Cs⁺ < Rb⁺ < K⁺ < Li⁺ for HMnO(Li) and Li⁺ Na⁺ < Cs⁺ < K⁺ < Rb⁺ for HMnO(Na) and HMnO(K). The high selectivity of Li⁺ on HMnO(Li) can be ascribed to an ion-sieve effect of spinel-type manganese oxide which was produced from LiMn₂O₄ Since HMnO(Na) and HMnO(K) had [2 × 2] tunnels of edge-shared [MnO₆] octahedra, the high selectivities of K⁺ and Rb⁺ on these samples were used to explain that the sizes of the [2 × 2] tunnels were suitable for filling ions of about 1.4 Å in radius in a stable configuration. The order of metal-ion uptake from seawater was Sr²⁺ < K⁺ < Mg²⁺ < Ca²⁺ < Na⁺ < Li⁺ for HMnO(Li), Li⁺ < Sr²⁺ < Mg²⁺ < Ca²⁺ < Na⁺ < K⁺ for HMnO(Na), and Li⁺ < Sr²⁺ < Ca²⁺ < Mg²⁺ < K⁺ < Na⁺ for HMnO(K).     

Alkali metal tungsten bronze-doped energy-saving glasses for near-infrared shielding applications

Tungsten bronze has attracted global attention for its applications in near-infrared (NIR)-shielding windows. Here, alkali metal tungsten bronze (M_xWO₃, M = one or two types of Li, Na, and K)-doped glasses are prepared by a simple melt-quenching method. Their structure and properties were characterized by XRD, Raman spectroscopy, XPS and UV–Vis–NIR spectrophotometry. The effects of M on their structure and the NIR shielding performance are investigated. The LiF sample has the best NIR shielding performance, but its visible transmittance is sacrificed due to its low quality. The glasses containing mixed Li⁺ and K⁺ cooperate to form a high-quality Li⁺/K⁺-codoped tungsten bronze, while the glasses containing mixed Li⁺ and Na⁺ compete for limited tungsten resources to form Li⁺- and Na⁺-doped tungsten bronzes separately. The research here is helpful for understanding the role of different alkali metal ions in bulk energy-saving glass and is hugely significant for the guidance of the future applications of energy-saving glass without films.     

Complete Li+ exchange into zeolite X (FAU, Si/Al = 1.09) from undried methanol solution

Complete exchange of Li⁺ into zeolite Na-X, |Na₉₂|[Si₁₀₀Al₉₂O₃₈₄]-FAU, was accomplished using undried methanol solvent (water concentration 0.02 M). A crystal of Na-X was treated with 0.1 M LiNO₃ in the solvent at 333 K, followed by vacuum dehydration at 673 K and 1 × 10^?6 Torr for 2 days. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques, in the cubic space group $ Fd\overline{3} $ at 100(1) K. The 92 Li⁺ ions per unit cell are found at three different crystallographic sites. The 32 Li⁺ ions occupy at site I’ in the sodalite cavity: these Li⁺ ions are recessed 0.28 Å into the sodalite cavity from their 3-oxygens plane [Li–O = 1.903(5) Å and O–Li–O = 117.8(3)°]. Another 32 Li⁺ ions are found at site II in the supercage, being recessed 0.26 Å into the supercage [Li–O = 1.968(5) Å and O–Li–O = 118.3(3)°]. The remaining 28 Li⁺ ions are located at site III in the supercage [Li–O = 2.00(8) Å].     

Ion exchange properties of NASICON-type ceramics—Application to ion selective electrodes

The ion-exchange properties of NASICON type ceramics of composition Na₃Zr₂Si₂PO₁₂ were investigated in aqueous solutions of NaCl, LiCl and KCl. The solution analysis shows that the [Zr₂Si₂PO₁₂] framework strongly prefers Na⁺ ion relative to K⁺ and Li⁺. The exchange current density of the alkali-cations at the NASICON/solution interface determined by impedance measurements varies in the order Na⁺>Li⁺>K⁺. These results agree well with the selectivity coefficients of Na⁺ ion selective electrodes based on NASICON. The interference process to alkali-cations in the NASICON based electrode was shown to result from an ionic exchange. The selectivity was suggested to be governed by the mobility of the cation inside the NASICON framework.     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS. XXXXI. ION EXCHANGE EQUILIBRIA OF ALKALI METAL IONS/HYDROGEN IONS ON TIN(IV) ANTIMONATE

Ion exchange equilibria of alkali metal ions (Li⁺, Na⁺, K⁺,, Rb⁺, and Cs⁺)H⁺, systems have been studied in MNO-j-HNOj media with ionic strength of 0.1 at 30, 45 and 60 °C on tin(IV) antimonate as a cation exchanger. The ion exchange isotherms have been measured for both forward and backward reactions by the batch technique. The isotherms showed S-shaped curves for all exchange systems studied. The selectivity coefficients (logarithmic scale) vary with the equivalent fraction X_M of alkali metal ions in the exchanger and give two linear functions of X_M with a break point (X_M= 0.14, except 0.04 for Li⁺, /H⁺) indicating two different exchanging sites. The selectivity sequence, Na⁺, ? K⁺, ? Rb⁺, ? Cs⁺, ? ? Li, holds in the range of Xu= (0 - 0.04) and the sequence, Cs < Rb ⁺, ? K ⁺, ? Na ⁺, < Li ⁺, applies when X_M is higher than 0.14.

Hypothetical thermodynamic data on “zero loading” of the ion exchange reaction was evaluated.     

Li1.6Mn1.6O4/PVDF多孔膜的制备及提锂性能

自制锂离子筛前驱体Li_1.6Mn_1.6O₄，并将Li_1.6Mn_1.6O₄粒子与高分子树脂PVDF杂化制膜，研究了膜经稀盐酸抽锂后对锂的吸附性能以及多次吸附与脱附性能等。结果表明，膜M-10-55[Li]采用0.5 mol·L^-1 HCl溶液抽锂约2 h锂的脱出基本达到平衡，Li⁺的洗脱率在95%左右，锰的溶损率为3.5%左右。抽锂后得M-10-55[H]对富锂溶液中锂的吸附约12 h达平衡，对锂的吸附容量较高为41 mg·g^-1，在第5次吸附时对锂的提取量为35 mg·g^-1左右。相比于Na⁺、K⁺、Mg²⁺、Ca²⁺，该膜对Li⁺表现出较好的选择性，对于从海水、盐湖卤水等液态锂资源中提取锂有很大的开发潜力。     

Cation-directed orientation of amines in ternary graphite intercalation compounds

1,2-Diaminopropane (1,2-DAP) provides an unusual example of an organic co-intercalate where graphite intercalation compounds (GICs) show intra-gallery orientation dependant on the identity of the alkali metal cation intercalate (Li⁺, Na⁺, or K⁺). The GIC gallery heights, K(1,2-DAP)_yC_x = 0.697 nm and Li(1,2-DAP)_yC_x = 0.782 nm, indicate 1,2-DAP long axis orientations that are parallel or perpendicular to the graphene sheets, respectively.     

THE A1-13-PHOSPHATOANTIMONIC ACID SYNTHESIS AND ION EXCHANGE PROPERTIES

Abstract

ABSTRACT The AI-13-phosphatoantimonic acid Al-13-Sb₃P2O₁₄.x H₂O has been prepared starting from K₃Sb₃p₂O₁₄. Thermal behaviour has been studied using TGA and DTA. pH titration curves of Al-13-phosphatoantimonic acid with alkali, hydroxide solutions (Na⁺, K ⁺ and Li⁺) shows a very promising ion exchanger. However, the capacities of the alkali metal were 4.08, 4.32 and 7.2 meq/g for Li⁺, Na⁺ and K⁺ respectively.     

Interactions of Some Hofmeister Cations with Sodium Dodecyl Sulfate in Aqueous Solution

In this work, we have investigated the influence of some alkali metal ions on the Krafft temperature (T_K) and critical micelle concentration (CMC) of a classical ionic surfactant, sodium dodecyl sulfate (SDS), over a wide range of temperature. The alkali metal cations such as Li⁺, Na⁺, Cs⁺, and K⁺ are found to affect the solubility and hence the T_K of the surfactant. It was observed that kosmotropic Li⁺ lowers the T_K of the surfactant. Due to the common ion effect, the solubility of SDS decreases in the presence of Na⁺, resulting in an increase in the T_K. On the other hand, chaotropic K⁺ and Cs⁺, capable of forming contact ion pairs with the chaotropic dodecyl sulfate ion, lower the solubility and hence elevate the T_K. In terms of decreasing the T_K, the ions follow the trend: Li⁺ > Na⁺ > Cs⁺ > K⁺ except for 0.0025 M CsCl. The added cations screen the charge of the micelle surface and facilitate closer packing of the surfactant with a consequent decrease in the CMC. In terms of the effectiveness in lowering the CMC, the ions follow the order: Cs⁺ > K⁺ > Na⁺ > Li⁺. In the presence of added electrolytes, the γ_CMC values are found to be lower than the corresponding values in pure water. The thermodynamic parameters (Gibbs free energy, enthalpy, and entropy changes) of micellization were calculated to gain insights into the mechanism of the process.     

Enhancement of fluorescence and magnetic properties of CeF3:RE3+ (Tb,Gd) nanoparticles via multi-band UV excitation and Li doping regulation

In this study, hydrothermal synthesis of CeF₃: Tb, Gd nanoparticles doped with Li⁺ alkali metal ions were demonstrated using introduction of Li⁺ ions through LiNO₃ nitrate. These nanoparticles have dual properties of magnetic fluorescence. X-ray diffraction, Fourier transform infrared spectrometer, XPS and photoluminescence spectra, and vibrating sample magnetometry were used to characterize structural properties, surface functional groups, fluorescence, and magnetic properties of these particles. Results show that CeF₃: Tb, Gd nanoparticles exhibit bright green light emission under excitation at 258 nm and 378 nm ultraviolet band. Through the modification of Li⁺ ions, luminous intensity of green light is further improved. Energy transfer between rare earth ions was investigated via photoluminescence spectroscopy. This work demonstrates potential applications of Li doped CeF₃: Tb, Gd nanoparticles as photomagnetic dual-functional materials in fields of biological imaging, solid state lighting, and magnetic biological separation.     

Role of ionic liquids in the efficient transfer of lithium by Cyanex 923 in solvent extraction system

The solvent extraction of Li⁺ by Cyanex 923 was investigated upon the addition of different imidazolium-based ionic liquids (ILs). The results showed 1-hydroxylethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf₂]) can improve the extraction of Li⁺ most effectively. The fundamental mechanism is that [HOEmim][NTf₂] can remarkably enhance the coordination ability of Cyanex 923 to Li⁺ to form more stable and hydrophobic ion-pair species [Li(Cyanex 923)_n][NTf₂] (n_max = 3) resulting from the electrostatic interaction and typical hydrogen bonding of IL, and thus facilitating the transfer of Li⁺ into organic phase. This work has revealed the transfer mechanism of Li⁺ in a solvent extraction system comprising of IL and neural ligand. The knowledge of the coordination environment of Li⁺ in the presence of IL also gives us a new insight into the separation of ⁶Li/⁷Li. The disadvantage of this process is the loss of IL. However, this study provides guidance for the design of better IL-based systems for the separation of metal ions.     

Electrochemical properties of modified copper-thallium hexacyanoferrate electrode in the presence of different univalent cations

The preparation of copper(II) hexacyanoferrate (CuHCF) films on the surface of gold electrodes as well as their characterization in solutions of various alkali metal and NH₄⁺ cations and in the presence of thallium(I) are described. The electrochemical quartz crystal microbalance and cyclic voltammetric techniques were used. In 0.50 M lithium nitrate, even at submillimolar concentration of Tl(I), the formal potential of CuHCF was shifted to more positive values. At higher Tl(I) concentrations, the formal potential of the CuHCF redox reaction changed linearly with the logarithm of Tl(I) concentration (in the 0.50 M solution of lithium or another alkali metal nitrate). From such dependencies, selectivity coefficients K_Tl/M were calculated, and they show that the CuHCF film on the gold electrode interacts preferentially with Tl(I). High affinity of Tl(I) to copper hexacyanoferrate, that was observed in the presence of alkali metal cations, was explained by relatively strong donor-acceptor interactions of Tl(I) ions with nitrogen in CN groups of the CuHCF film.It was also shown for simple M₄[Fe(CN)₆] metal ferrocyanate salts (where M = Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺ and Tl⁺) that there is a preferential interaction of Tl⁺ with CN group consistent with formation of a Tl-NC-Fe bridge.     

Selective Transport of Alkali and Alkaline Earth Metallic Ions through a Supported Liquid Membrane Containing Tripentyl Phosphate as a Carrier

Abstract

A selective transport system for alkali and alkaline earth metallic ions with a perchlorate ion as a pairing ion species through a supported liquid membrane (SLM) containing tripentyl phosphate (TPP) as a carrier is described. The SLM used is a porous polypropylene membrane impregnated with TPP solution in o-nitrophenyloctylether. The effects of the pairing ion species, the initial perchlorate concentration, and the TPP concentration on metallic ion transportability are examined under various experimental conditions. The permeation velocities of the metallic ions in the transport system followed the sequence Li⁺?Na⁺>K⁺>Mg²⁺; that is, a highly selective transport for Li⁺ ion was observed. Compared with the transport rates of alkali metallic ions, those of transition metallic ions such as Cu²⁺ and Fe³⁺ ions are very low. The permeation velocities of alkali and alkaline earth metallic ions through an SLM are dependent on the concentrations of perchlorate and TPP. Equations for the permeation velocities of Li⁺, Na⁺, K⁺, and Mg²⁺ ions through an SLM, based on two concentrations of perchlorate and TPP, are proposed.     

Factors influencing the structure of electrochemically prepared α-MnO2 and γ-MnO2 phases

The α- and γ-phases of MnO₂ prepared by electrolysis of MnSO₄ and M_xSO₄ (where M = Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺ or Mg²⁺) in aqueous solutions at various pH and voltage E_v values under ambient conditions have been systematically studied. The structures of powdery MnO₂ produced are found to depend on the radius of the M^z+ counter cation in addition to the pH and E_v conditions. In order to achieve the α-phase for MnO₂ formation under neutral pH condition, the radius of counter cation must be equal to or greater than 1.41 Å, the size of the K⁺ cation. The relative concentration ratio of [MnO₄⁻]_transient/[Mn²⁺], which is related to the pH-E_v conditions, also affects the structure of MnO₂ produced with counter ions smaller than K⁺. For samples prepared in acidified solution with the counter ions of Li⁺, Na⁺ or Mg²⁺ at 2.2 V, the electrolysis products display the γ-MnO₂ phase while those prepared at 2.8 V electrolysis produce a mixture of γ-MnO₂ and α-MnO₂ phases. Single phase of α-MnO₂ is identified in the 5 V electrolysis products. Furthermore, the valence state of manganese was found to decrease as the applied voltage was reduced from 5.0 to 2.2 V. This implies that the lower [MnO₄⁻]_transient/[Mn²⁺] ratio or the less oxidative condition is responsible for the non-stoichiometric MnO₂ structure with oxygen deficiency.     

CO<Subscript>2</Subscript> retention ability on alkali cation exchanged titanium silicate,ETS-10

ETS-10 was ion exchanged by various alkali cations (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) and the BET surface area and pore volume was exactly consistent with cationic size; that is, in the order of Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺. It was observed that a single point adsorption capacity was inversely proportional to cationic size. The largest CO₂ capacity was observed for Li⁺-ETS-10 and it is attributed to greater cation–quadrupole interactions with CO₂ than larger cation. The results also suggests that as the CO₂ loading is increased, the accessibility of adsorbing CO₂ to framework basic O⁻ sites should have become difficult with the increase in cationic size due to the blocking effect by extra-framework CO₂-M⁺. The slight decrease in the slope of adsorption capacity with temperature, especially beyond 373 K for Li⁺-ETS-10 and K⁺-ETS-10 suggests that the adsorption of CO₂ on small alkali cation exchanged-ETS-10 at high temperature is somewhat associated with basic oxygen anion sites in framework due to the existence of large pore. The CO₂-TPD results show that the amount of desorbed CO₂ at higher temperature was proportionally increased due to the increased basicity of oxygen anions in framework. It also shows that the desorption temperature associated with alkali cations in extra-framework (corresponding to low temperature desorption peak) has been lowered with the increase in cationic size, indicating weak cation–quadrupole interactions with CO₂ for larger cations.     

Isopolyoxorhenates observed by positive ion electrospray mass spectrometry

Unknown positive ion isopolyoxorhenates have been observed using electrospray ionization mass spectrometry (ESI+). The ESI+ studies of ammonium and alkali metal (Na⁺ and K⁺) perrhenate salts in aqueous solution at pH 4.5 show the existence of the series [A_x+1Re^VII_xO_4x]⁺ (where x=1–5 and A=NH₄⁺, Na⁺ and K⁺). In the potassium perrhenate system, the series [K_x+2Re^VRe^VII_xO_4x+3]⁺ (x=0–4) has also been characterised. All of these four series have {AReO₄} as the aggregation unit. In the ammonium perrhenate system, the monomeric Re(VII)-containing species, [(NH₄)₂(H₂ReO₅)]⁺, [(NH₄)₃(HReO₅)]⁺ and [(NH₄)₄(ReO₅)]⁺ were also detected.     

Biochemical,functional, and histochemical effects of essential fatty acid deficiency in rat kidney

The present study was designed to examine the effects of EFA deficiency (EFAD) on biochemical, functional, and structural aspects of the kidney in growing and adult rats fed a normal or EFAD diet for 9 wk after weaning. Food and fluid intake (FI), urine volume, and Na⁺ and K⁺ excretions were measured weekly from weeks 4 to 8 by placing the rats in individual metabolic cages for 24 h. At week 9, Li⁺ and a 5% water load, respectively, were administered at 14 and 1.5 h prior to glomerular and proximal tubular function studies, as assessed by 3-h creatinine (C_Cr) and Li⁺ (C_Li+) clearances. Hematocrit and urine volume; serum and urine [Cr], [Li⁺], [Na⁺], and [K⁺]; and renal FA distribution were also measured. Data [corrected to 100 g/body weight (bw) and presented as means ±SEM] were significant, at P<-0.05. Despite a similar ingestion of solids from weeks 4 to 7 (weeks 7 to 10 of life), the rats on the EFAD diet showed a decreased body weight from week 5. From weeks 4 to 8, Fl and urine volume were similar for both groups, but the Fl increased at week 6 in the EFAD group; 24-h Na⁺ and K⁺ excretions were similar at all weeks, except for an increase in the EFAD group for both ions at week 7. In the EFAD group, C_Cr and C_Li+ decreased by 27 and 56.3%, respectively (385.7±33.4 vs. 280±21.1, and 21.0±2.1 vs. 9.2±1.1 μL/min/100 g; n=9 vs. 10), the latter result suggesting increased proximal reabsorption. The 3-h Na⁺ and K⁺ excretions were similar, but the Li⁺ decreased (0.78±0.06×10⁻² vs. 0.32±0.03×10⁻² μeq/min/100 g) in the EFAD group, giving additional support to the suggestion. Renal structure was normal and similar for both groups, but the EFAD group showed a more prominent proximal tubule brush border, together with heavier periodic acid-Schiff staining in all specimens from weeks 5 to 9. In the EFAD group, FA of the n−9 and n−7 series were higher, but most of the n−6 series were lower as a percentage of total lipids in the medulla and cortex. Medullary levels of 20∶4n−6 were maintained, 22∶4n−6 declined twice, arachidonic acid was maintained, and 20∶5n−3 was lower. The EFAD diet affected glomerular function, proximal tubular structure and function, and FA distribution in the rat kidney.     

Development of a glass matrix composition for light-colored heat-resistant glass ceramic coating for nichrome alloys

The specifics of glass formation in the R₂O ? Al₂O₃ ? SiO₃ ? TiO₂ multicomponent system (R=Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺) are considered. Regions of glass ceramic compositions are identified and the specifics of structure and phase formation of glass ceramic matrices are investigated. An optimum composition is determined, which can be used as a glass matrix for light-colored heat-resistant glass ceramic coating.     

Diffusion potentials and transport numbers in molten alkali chlorides and their binary mixtures

Diffusion potentials at porous asbestos diaphragms separating chloride melts of different cation compositions have been measured as functions of temperature making use of cells with chlorine electrodes. Between individual molten alkali chlorides the diffusion potentials were found to increase with the difference in their cation radii reaching a maximum of ～ 35 mV for

and a minimum of ～ 2 mV for

The melts with smaller alkali cations were more electropositive in all cases. From the experimental data for the systems

where M₁  Cs or K and M_II  Li or Na, transport numbers of those cations were computed as functions of N. They proved to be smaller for Li⁺ and Na⁺ and larger for Cs⁺ and K⁺ as compared with their additive values. The cation mobilities were calculated. For Cs⁺ or K⁺ they are a little higher in the salt mixtures than in their individual chlorides whereas for Li⁺ or Na⁺ they are considerably lower. Such changes in cation transport numbers and mobilities can be explained in terms of autocomplex structure model for molten alkali halides developed recently by M. V. Smirnov.     

Alkali binding in hydrated Portland cement paste

The alkali-binding capacity of C-S-H in hydrated Portland cement pastes is addressed in this study. The amount of bound alkalis in C-S-H is computed based on the alkali partition theories firstly proposed by Taylor (1987) and later further developed by Brouwers and Van Eijk (2003). Experimental data reported in literatures concerning thirteen different recipes are analyzed and used as references. A three-dimensional computer-based cement hydration model (CEMHYD3D) is used to simulate the hydration of Portland cement pastes. These model predictions are used as inputs for deriving the alkali-binding capacity of the hydration product C-S-H in hydrated Portland cement pastes. It is found that the relation of Na⁺ between the moles bound in C-S-H and its concentration in the pore solution is linear, while the binding of K⁺ in C-S-H complies with the Freundlich isotherm. New models are proposed for determining the alkali-binding capacities of C-S-H in hydrated Portland cement paste. An updated method for predicting the alkali concentrations in the pore solution of hydrated Portland cement pastes is developed. It is also used to investigate the effects of various factors (such as the water to cement ratio, clinker composition and alkali types) on the alkali concentrations.