Inorganic Ion-exchange Materials Research Articles

Microwave assisted green synthesis and characterization of new phase inorganic ion-exchange materials: bismuth tungstate and stannic arsenate

Microwave assisted green synthesis and characterization of new phase inorganic ion-exchange materials: bismuth tungstate and stannic arsenate

Kinetics of ion exchange on inorganic sorbents

In recent years, the problems associated with water use have sharply escalated worldwide. One of the main methods used for these purposes is ion exchange. In turn, the most promising ion-exchange materials are inorganic ion exchangers - substances with exceptionally high selectivity concerning ions of certain elements. In connection with life, it is necessary to understand ion exchange mechanisms on inorganic ion exchangers since they have significant differences in the unit vector of classical ion exchange resins. A theoretical analysis was conducted, which made it possible to reveal some features of the sorption kinetics of inorganic ion exchange materials. It has been found that when working in the region of concave isotherms, a significant slowdown of the mass transfer process is possible even on very sorbent granulates. This effect is associated with reversing sorption processes involving highly selective sorbents. In this regard, difficulties can be encountered when using displacement desorption, which is associated with maintaining high concentrations of the displacing agent and the low rate of the ion exchange process. The rate of sorption on inorganic ion exchange materials depends in a certain way on the concentration of sorbed ions in an external solution. This dependence manifests itself even in the absence of external diffusion inhibition. In this case, the determining factor is the distribution of electrolytes between the pore space of the granule and the free volume of the solution. The rate of mass transfer processes with the participation of inorganic sorbents can be affected not only by the permeability of granulates but also by inhibition at the level of homogeneous sections of the solid phase. The simplest way to detect such deceleration is to compare the data of the kinetic experiment with the theoretical results related to the model that ignores deceleration at the level of homogeneous sections of the solid phase. In such a comparison, it is necessary to consider possible distortions due to the finite width of particle size fractions, the discrepancy between the particle shape and the calculated one, etc.

Sulfur-modified zeolite A as a low-cost strontium remover with improved selectivity for radioactive strontium

Selective removal of radioactive strontium (90Sr) from the environment is important, and selective adsorption/ion exchange is appropriate for removal of trace amounts of 90Sr from large volumes of 90Sr-contaminated water. Although various inorganic ion-exchange materials, including zeolites, have been investigated intensively for removal of Sr2+ due to their excellent resistance to radiation and high ion-exchange capacity, their ion-exchange selectivity for Sr2+ is poor in the presence of competing ions such as Ca2+ and Mg2+. Here, sulfur-modified NaA zeolite (S-NaA) was prepared for low-cost, selective 90Sr removal because the elemental sulfur encapsulated in micropores provides additional Lewis acid-base interactions with Sr2+ during the Sr2+ ion-exchange. Our ion-exchange experiments revealed that S-NaA with 3 wt% sulfur (3 S-NaA) showed the highest Sr2+ selectivity among various S–NaAs containing up to 10 wt% sulfur because ion exchange involving bulky hydrated Sr2+ depends on the reduced micropore volume of S-NaA after sulfur loading. Most importantly, 3 S-NaA effectively and efficiently (>99.4%) removed 90Sr from groundwater containing 8.4 ppt 90Sr, demonstrating its excellent potential for practical application in the treatment of 90Sr-contaminated water.

Metal Doping Silicates as Inorganic Ion Exchange Materials for Environmental Remediation

Environmental remediation of hazardous metals like Cd(II), and Co(II) ions is very necessary due to their toxicity at trace and accumulation levels in the biosystem. In this study, the sorption of Co(II), and Cd(II) ions from aqueous solutions onto titano-silicate (TiSi) ion exchange material and in-situ dopping composites cobalt titano-silicate (Co-TiSi) and cadmium titano-silicate (Cd-TiSi) was achieved. TiSi and in-situ dopping composites were obtained by precipitation technique and characterized using different analytical tools such as FT-IR, XRD, TGA&DTA, and XRF. Results obtained from this study showed that the capacity for Co(II), and Cd(II) ions revealed that Co-TiSi and Cd-TiSi is a higher capacity than those obtained for TiSi by 1.81, and 1.41 times value, respectively. The distribution coefficients for Co-TiSi as a function of HNO3 have high separation factors for Co(II) at different HNO3 concentrations. Langmuir isotherm model is the most representative for discussing the sorption process with a maximum sorption capacity of 16.02, and 10.96 mg/g for Co(II), and Cd(II) ions, respectively. Co-TiSi is suitable for the column technique for the recovery of studied cations. The investigation proved that a Co-TiSi exchanger is suitable for the uptake of the studied ions from liquid solutions and could be considered as potential material for the refining of effluent polluted with these ions.

Novel Inorganic Integrated Membrane Electrodes for Membrane Capacitive Deionization.

In capacitive deionization (CDI), coion repulsion and Faradaic reactions during charging reduce the charge efficiency (CE), thus limiting the salt adsorption capacity (SAC) and energy efficiency. To overcome these issues, membrane CDI (MCDI) based on the enhanced permselectivity of the anode and cathode is proposed using the ion-exchange polymer as the independent membrane or coating. To develop a novel and cost-effective MCDI system, we fabricated an integrated membrane electrode using a thin layer of the inorganic ion-exchange material coated on the activated carbon (AC) electrode, which effectively improves the ion selectivity. Montmorillonite (MT, Al2O9Si3) and hydrotalcite (HT, Mg6Al2(CO3)(OH)16·4H2O) were selected as the main active anion- and cation-exchange materials, respectively, for the cathode and anode. The HT-MT MCDI system employing HT-AC and MT-AC electrodes obtained a CE of 90.5% and an SAC of 15.8 mg g-1 after 100 consecutive cycles (50 h); these values were considerably higher than those of the traditional CDI system employing pristine AC electrodes (initially, a CE of 55% and an SAC of 10.2 mg g-1, which attenuated continuously to zero, and even "inverted work" occurs after 50 h, i.e., desorption during charging and adsorption during discharging). The HT-MT MCDI system showed moderate tolerance to organic matters during desalination and retained 84% SAC and 89% CE after 70 cycles in 50-200 mg L-1 sodium alginate. This study demonstrates a simple and cost-effective method for fabricating high-CE electrodes for desalination with great application potential.

Thermal treatment of Cs-exchanged chabazite by hot isostatic pressing to support decommissioning of Fukushima Daiichi Nuclear Power Plant

Ion exchange materials are used widely for the removal of radionuclides from contaminated water at nuclear licensed sites, during normal operating procedures, decommissioning and in accident clean-up, such as the ongoing recovery operation at the Fukushima Daiichi nuclear power plant. Framework silicate inorganic ion exchange materials, such as chabazite ((Na0.14K1.03Ca1.00Mg0.17)[Al3.36Si8.53O24]•9.7H2O), have shown particular selectivity towards 137Cs uptake, but their safe storage poses a number challenges requiring conditioning into passively safe waste packages of minimal volume. We demonstrate the transformation of Cs-exchanged chabazite into a glass-ceramic wasteform by hot isostatic pressing to produce a durable consolidated monolith. The application of heat and pressure resulted in the collapse of the chabazite framework, forming crystalline Cs-substituted leucite (Cs0.15(3)K0.57(4)Al0.90(4)Si2.24(5)O6) incorporated within a K2O-CaO-MgO-Al2O3-SiO2 glass. The Cs partitioned preferentially into the Cs/K-feldspar which incorporated ~77% of the Cs2O inventory. Analysis of the chemical durability of the glass-ceramic wasteform revealed that the Cs release rates were comparable or lower than those reported for vitrified high level and intermediate level wastes. Overall, hot isostatic pressing was demonstrated to be an effective processing technology for conditioning spent inorganic ion exchange materials by yielding durable and passively safe wasteforms.

Revisiting the Old and Golden Inorganic Material, Zirconium Phosphate: Synthesis, Intercalation, Surface Functionalization, and Metal Ion Uptake

As a fascinating two-dimensional (2D) layered inorganic ion exchange material, zirconium phosphate (hereafter ZrP) has drawn interdisciplinary attention as an ion exchange material and a competent host for surface functionalization and intercalation. This is due to its captivating properties such as simple synthesis procedure, excellent ion-exchange capacity, excellent chemical, thermal, and radiolytic stability, tunable interlayer gallery, and good biocompatibility. Among all the well-known phases of ZrP, we restrict our discussion only to the alpha (α-ZrP) and gamma (γ-ZrP) phases for their efficient ion exchange performance and more tunable interlayer spacing. This review summarizes a panorama of the recent research progress on the synthesis, intercalation, and surface functionalization of ZrP with organic molecules, metal complexes, and metal ions for the design and fabrication of self-assembled monolayers, layer-by-layer assemblies, and nanocomposites. Within the confined gallery microenvironment of ZrP, usual molecules behave unusually with dramatic enhancement in the photophysical properties. The intercalation of metal complexes and their fascinating electronic properties will also be comprehensively highlighted in this review. Furthermore, for the first time, a cutting-edge advancement (2010 onward) of the versatile adsorption performance of ZrP-based materials for the uptake of toxic metal ions which include nuclear waste-related metal ions, heavy metal ions, and rare earth ions will be presented in detail. Last but not least, the review will conclude with the summary and future directions, which will provide new research opportunities for the development of ZrP based sustainable heterofunctional material.

Ion-Exchange Kinetics of Alpha-Zirconium Phosphate Nanoplatelets for Application in Targeted Alpha Therapy

ABSTRACT The loading and kinetics of uptake for the inorganic ion-exchange material, α-zirconium phosphate, Zr(HPO4)2•H2O, were investigated with ions relevant to targeted alpha therapy including natural Cs+ (as a surrogate for 221Fr), natural Bi3+ (as a surrogate for 213Bi), and natural La3+ (as a surrogate for 225Ac). The narrow interlayer spacing of the α-phase (d = 7.6 Å) was found not to be advantageous with respect to rapid ion exchange, while converting the material to the hydrated Na-phase (d = 12.2 Å) allowed ion exchange to proceed more quickly, reaching equilibrium in under an hour. High loading was achieved for all three ions, at 72 ± 4% for Cs+ and 95 ± 5% for La3+ at pH 3 and 108 ± 10% for Bi3+ at pH 0.5. Leaching profiles of the loaded materials in a simulated human plasma environment of 10 mM carbonate buffer at pH 7.4 and 37°C, showed negligible release, with less than 1% in all cases. The ion-exchange properties and overall benign nature of zirconium phosphate highlight these materials as a promising platform for a targeted alpha therapy drug-delivery vehicle.

Sulfur-modified chabazite as a low-cost ion exchanger for the highly selective and simultaneous removal of cesium and strontium

Low-cost inorganic ion-exchange materials with improved Cs+ and Sr2+ selectivities are of great interest for the treatment of various radioactive liquid wastes. Here the sulfur-modified chabazite (CHA) was formed by the simple encapsulation of elemental sulfur in the micropores of CHA for the cost-effective simultaneous removal of Cs+ and Sr2+. Our results showed that the Cs+ selectivity increased as the sulfur loading increased because of the enhanced Lewis acid − base interaction between sulfur and Cs+. On the other hand Sr2+ selectivity slightly increased with sulfur loading up to 5 wt% and decreased thereafter. Consequently distribution coefficients (Kd) of CHA containing 5 wt% sulfur (5S-CHA) are 3 × 106 mL/g for Cs+ and 2 × 105 mL/g for Sr2+ which are higher than those of previously reported Cs+ and Sr2+ ion-exchange materials. Moreover the 5S-CHA exhibited excellent simultaneous removal performances for 137Cs and 90Sr in simulated groundwater with Kd values of 9.1 × 104 mL/g for 137Cs and 7.8 × 104 mL/g for 90Sr which are much higher than or similar to those of commercial CHA and crystalline silicotitanate. Due to the easily scalable procedure using commercially available zeolites and very cheap elemental sulfur 5S-CHA has excellent potential for the treatment of a large volume of 137Cs- and 90Sr-contaminated water.

Evaluation of Inorganic Ion Exchange Materials for Purification of 225Ac from Thorium and Radium Radioisotopes

Evaluation of Inorganic Ion Exchange Materials for Purification of 225Ac from Thorium and Radium Radioisotopes

Evaluation of Inorganic Ion Exchange Materials for Purification of 225Ac from Thorium and Radium Radioisotopes

Evaluation of Inorganic Ion Exchange Materials for Purification of 225Ac from Thorium and Radium Radioisotopes

Tunable optical and dielectric properties of polymeric composite materials based on magneso-silicate

Magneso-silicate (MgSi) as an inorganic ion exchange material was synthesized by a precipitation technique. Then, the MgSi was impregnated into polyacrylamide acrylic acid and its composites (Poly) by condensation polymerization. To study the effect of $$\upgamma $$ -radiation, the polyacrylamide acrylic acid and its MgSi samples were synthesized using $$\upgamma $$ -irradiating systems at 25, 65 and 90 kGy. The variations in the radiation dose and amorphous structure were altered and confirmed by X-ray diffraction (XRD). Moreover, the absorbance and band-gap energy were enhanced by inserting MgSi into the polymeric composites (Poly). Furthermore, variations in temperature with dielectric constant, dielectric loss and conductivity of the samples at various frequencies from 100, 500, 1000, 2000 to 4000 Hz have been explained.

Associated petroleum waters, as a promising source of lithium

In this paper we attempted to estimate the size of mineral resources that are poor in lithium content Due to possible depletion of existing resources poor resources can become the most promising source of resources Possible directions and prospects f lithium extraction from poor sources of raw materials which are underground waters associated oil waters The directions for solving these problems are continued Nowadays hydro mineral raw materials gradually become the main source of lithium In view of complexity of the salt composition of hydro mineral raw materials the use of highly selective inorganic ion exchange materials is the most promising method for recovery of lithium

Synergy between Zeolite Framework and Encapsulated Sulfur for Enhanced Ion-Exchange Selectivity to Radioactive Cesium

To eliminate the radioisotope 137Cs+ from contaminated water, various inorganic ion-exchange materials have been developed. Many selective ion-exchange materials are relatively expensive and difficult to prepare, whereas conventional materials such as aluminosilicate zeolites lack ion-exchange selectivity in the presence of competing cations. Here, we report a simple but powerful strategy to significantly increase the Cs+ selectivity of conventional zeolites. We demonstrate that encapsulation of elemental sulfur in the micropores of zeolites (NaA, NaX, chabazite, and mordenite) via vacuum sublimation can remarkably increase the selectivity toward Cs+ in the presence of competing ions. It appears that the elemental sulfur does not provide additional adsorption sites for Cs+ ions but increases the ion-exchange selectivity toward Cs+ by providing additional interaction. Various analyses show that sulfur partially donates its electron to the ion-exchanged Cs+ cations in zeolites, indicating significant Lewis ...

Isotherm and kinetic sorption of some lanthanides and iron from aqueous solution by aluminum silicotitante exchanger

ABSTRACTSorption of La3+, Eu3+, and Fe3+ onto new synthetic inorganic ion exchange material of aluminum silicotitante was investigated. The aluminum silicotitante (EX1, EX2, and EX3) are synthetic with different concentration ratio (0.1:0.1:0.003, 0.1:0.1:0.1, and 0.1:0.1:0.1) at aging time 4, 4, and 1 day, respectively. The equilibrium kinetic for La3+, Eu3+, and Fe3+ onto EX1, EX2, and EX3 materials takes about 120 min which is considered as a fast kinetic process. Sorption results were fitted using different kinetic models such as pseudo-first-order, pseudo-second order, and intraparticle diffusion models. The results indicated that the sorption of La3+, Eu3+, and Fe3+ onto EX1, EX2, and EX3 materials is highly fit with the pseudo-second order model. Equilibrium data were described by the Langmuir, Freundlich isotherm models. The Langmuir isotherm model was fitted to the experimental data better than the Freundlich isotherm. The thermodynamics parameters (positive values of ΔH°, ΔS° and negative values of ΔG°) indicated the binding systems between the materials and adsorbate were endothermic, entropy gained and spontaneous in nature. The experimental data indicated that, aluminum silicotitante could be used as an efficient sorbent for La3+, Eu3+, and Fe3+. Maximum sorption % at equilibrium is 92.7, 99.0, and 78.5% for La3+, Eu3+, and Fe3+, respectively.

43.ハイパーコール製造のための脱アルカリ技術 : 溶剤脱灰炭の無機イオン交換材による処理

43.ハイパーコール製造のための脱アルカリ技術 : 溶剤脱灰炭の無機イオン交換材による処理

COMPARISON OF EXTRACTION METHODS OF LITHIUM AND ITS COMPOUNDS FROM NATURAL RAW MATERIALS

The paper deals with lithium (and its compounds) which is one of the promising materials used in hydrogen energy. Its individual and complex hydrides are used for storing and transporting hydrogen in hydrogen power plants. The paper compares the different methods of lithium extraction from natural raw materials. The main industrial techniques of processing spodumene and other lithium minerals are considered. Since the volumes of these mineral deposits in the world are limited, hydro-mineral raw materials gradually become the main source of lithium. The paper focuses on the analysis of methods for lithium containing hydromineralic raw materials processing. The paper indicates that at the first stage of lithium recovery (the production of its concentrates) there are the most commonly used the galurgical methods of concentrating and isolating lithium from natural brines. However, these methods are only applicable to rich natural lithium brines. Another method (the method of its deposition in the form of sparingly soluble compounds) is danger from the ecological point of view due to the large impact on these brines, and the problems of their further utilization. The sorption methods of lithium extraction, especially from poor in composition of natural and technological solutions, are more promising. In view of complexity of the salt composition of hydro-mineral raw materials, the use of highly selective inorganic ion-exchange materials is the most promising method for recovery of lithium too. In order to complete the general picture of lithium production, the paper analyzes the modern methods for obtaining metallic lithium and various lithium-containing compounds. Moreover, the paper describes the methods of reprocessing lithium carbonate into other compounds, as well as methods for obtaining lithium hydroxide and lithium chloride, and electrochemical and vacuum-thermal methods for obtaining metallic lithium. Furthermore, the methods of lithium refining and the need for processing secondary lithium resources are briefly considered.

Immobilization of strontium-loaded zeolite A by metakaolin based-geopolymer

Zeolites are the preferred inorganic ion exchange materials for purifying radioactive waste liquid. Radionuclide-loaded zeolites, which are considered to be radioactive waste, are strictly required to be encapsulated within a solid matrix. In this paper, we investigate the feasibility of immobilizing exhausted zeolite A, loaded with 90Sr radionuclide, in metakaolin based-geopolymer. The geopolymer solidification blocks had better mechanical performance and leaching resistance in deionized water, sulfuric acid, magnesium sulfuric and acetic acid buffer solutions than the cemented blocks. While the compressive strength of the geopolymer solidification product was 37.62MPa after curing for 28 days, the equivalent value for the cement block was only 11.32MPa. The geopolymer solidification blocks also exhibited even lower compressive strength loss after high-temperature and freeze-thaw cycles tests. XRD and EDS analysis indicated that most of the strontium radionuclide in the geopolymer solidification blocks was incorporated in the zeolite structure as the charge balancing cation. The microscopic analysis revealed that geopolymer matrix appeared more compact and dense, and encapsulated the Sr-loaded zeolite A more tightly than did the cement. Therefore, it could be concluded that metakaolin based-geopolymer are more compatible with exhausted zeolite A and present a remarkable advantage for radioactive waste immobilization.

Determination of precipitation regularities for nanoparticles of hydrated metal oxides in the anion exchange resin

Organic and inorganic ion-exchange materials containing incorporated inorganic particles of ion exchangers are characterized by enhanced selectivity for ions of toxic metals and resistant to poisoning by organic substances. An important task for achieve the necessary kinetic parameters of ion exchange is to reduce the size of the incorporated particles that is particularly important for hydrated oxides containing functional groups, mainly, on the outer surface of the particles. Regularities of forming Zr(IV), Fe(III), Al(III) oxide particles in a polymeric anion exchange matrix are considered in the article. The aim of research is establishing and experimental confirmation of deposition mechanism for inorganic ionite in the polymer for directional control of size and state of the particles. Using computer analysis of TEM images it was revealed that the fractal dimension of the aggregate particles is 2,38-2,72. Nature of modifier also determines the state of the polymer particles. The effect of these factors was analyzed using the Ostwald-Freundlich equation. It was established that the primary nanoparticle size is determined by reprecipitation. Accordingly, the formation mechanism of aggregates is association of nanoparticles with a small cluster, and the limiting step is the diffusion of the polymer nanoparticles. The equation for the diffusion flux of nanoparticles was obtained and it was shown that flux slowing leads to formation of dendritic multilevel structures. The results can be used to develop technologies for ionite synthesis, ion-exchange membranes and materials for baromembrane separation. The proposed approach allows to obtain materials with a given particle size and, consequently, with certain functional properties.

Removal of Strontium Ions by Synthetic Nano Sodalite Zeolite from Aqueous Solution

In this research, the zeolite sodalite, as an inorganic ion exchange material, was chemically produced in the template-free synthesis and evaluated in order to facilitate the sorption of strontium ions from aqueous solutions in batch operations onto acid treated zeolite with dilute H2SO4 solutions. The following indicates what the batch experiments included: a sorbent amount of 0.25 g in 100 mL of strontium solution (50 mg/L), a contact time of 80 min, pH 6 and a 20 oC temperature. To study the kinetics of removal process, three equations, i.e. Morris–Weber, Lagergren (pseudo first order) and pseudo second order were used. The sorption data were applied to the Langmuir, Freundlich, Dubnin-Randkovich (D-R) and Temkin models in order to estimate the sorption capacity, intensity and energy. An evaluation of the thermodynamic parameters ΔH, ΔS and ΔG was done. It was found out from thermodynamic parameters that the sorption of strontium onto zeolite was feasible, spontaneous and endothermic under studied conditions.