Rapid Ion Exchange Research Articles

In vitro Biomineralization Ability of Magnesium-Doped Coral Hydroxyapatite Coating Prepared by Pulsed Laser Deposition

Coral hydroxyapatite (CHA) is a calcium phosphate that has a similar inorganic composition to human bone and the porous structure of coral stone. Due to its interconnected network like pore structure, it can serve as a framework for bone conduction. In this study, CHA films and Mg-CHA films were deposited on titanium and silicon substrates by Pulsed laser deposition, and then the films were heat treated respectively. Studies on the adhesion of the coating showed that the heat-treated Mg-CHA film adhered better to the titanium substrate. The experimental study on biomineralization in vitro showed that a small amount of porous structure appeared in the heat-treated Mg-CHA after immersion in SBF for three days, and the porous structure was visible after immersion for seven days. After 14 days, a new apatite layer formed on the surface. This suggested that magnesium undergoes chemical corrosion in SBF, leading to rapid ion exchange, which results in the formation of porous structures and promotes the development of an apatite-like layer. In summary, the heat-treated Mg-CHA films had superior biomineralization properties.

In situ potassium and hydrogen ion exchange into a cubic zirconium silicate microporous material.

The selective separation of ions from aqueous systems, and even in the human body, is a crucial to overall environmental management and health. Nanoporous materials are widely known for their selective removal of cations from aqueous media, and therefore have been targeted for use as a pharmaceutical to treat hyperkalemia. This study investigated the detailed crystallographic molecular mechanisms that control the potassium ion selectivity in the nanoporous cubic zirconium silicate (CZS) related materials. Using time-resolved in situ Raman spectroscopy and time-resolved in situ X-ray diffraction, the selectivity mechanisms were determined to involve a synchronous cation-cation repulsion process that serves to open a favorable coordination bonding environment for potassium, not unlike the ion selectivity filter process found in potassium ion channels in proteins. Enhancement of ion exchange was observed when the CZS material was in a partial protonated state (≈3:1 Na:H), causing an expansion of the unit-cell volume, enlargement of the 7 member-ring window, and distortion of framework polyhedra, which allowed increased accessibility to the cage structures and resulted in rapid irreversible potassium ion exchange.

A new binder-free ZnS-CuO microsphere: A battery-type electrode material for asymmetric supercapacitor

The supercapacitor has emerged as a viable solution to address the energy demands of industries and mitigate the environmental concerns associated with fossil fuel utilization. Hence, in this study, binder-free ZnS-CuO microspheres are reported for the first time and directly utilized as a battery-type electrode for asymmetric supercapacitor (ASC) applications. The current study demonstrates an exceptional electrochemical performance by optimizing the composition, structure, and morphology. The increased surface area and abundance of active sites contribute to the enhanced ion transfer efficiency between the electrolyte and the electrode, promoting rapid ion exchange. The electrochemical properties reveal a maximum capacitance of 561 F/g with excellent charge storage capacity, and good rate capability. The CuO-ZnS||AC ASC was built that operates in a broad voltage window of 1.6 V, and a capacitance of 175 F/g in an aqueous solution. It delivers the highest specific energy of 62 Wh/kg with an excellent power delivery of 8640 W/kg and remarkable stability of 93.2 % after 5000 cycles. Nevertheless, there is a prevailing optimism regarding the potential for optimizing synthesis procedures, which may ultimately result in the practical implementation of these innovative materials for efficient energy storage in the near future.

Dual surfactants-assisted adsorption of lithium ions in liquid lithium resources on a superhydrophilic spinel-type H4Ti5O12 ion sieve

The industrial application scope of spinel-type titanium oxide ion sieves is limited by its low adsorption efficiency and regeneration performance. In this study, H4Ti5O12 (HTO-IV), a superhydrophilic spinel-type lithium ion sieve, was synthesized for the first time with the dual surfactants of CTAB and F127 to modulate the surface morphology and surface wettability of the raw material. The prepared HTO-IV lithium ion sieve was composed of ultrathin nanosheets assembled into microspheres and showed excellent surface hydrophilicity and an open hierarchical mesoporous structure, which allowed rapid ion exchange between Li+ and H+. Li+ adsorption rate exceeded 85 % within 30 min and its maximum theoretical adsorption capacity was 57.90 mg/g. The adsorption process of Li+ on HTO-IV followed a pseudo-second-order kinetic model and Langmuir adsorption isotherm model. HTO-IV also exhibited good adsorption selectivity towards Li+ in the presence of coexisting ions. Furthermore, the lithium adsorption ratio of the HTO-IV ion sieve remained at around 97 % even after five adsorption–desorption cycles, demonstrating excellent adsorption capacity and cycling stability. The study highlights the relationship between surface hydrophilicity and adsorption performance of the adsorbent.

Ultra‐Fast In Situ Reconstructed Nickel (Oxy)Hydroxide Nanoparticle Crosslinked Structure for Super‐Efficient Alkaline Water Electrolysis by Sacrificing Template Strategy

The rapid construction of water electrolysis catalysts by a sacrificing template in an electrochemical environment is rarely a concern. Herein, using a fluorine‐rich (F‐rich) nickel fluoride (NiF2) grown on nickel foam (NF) as a sacrificial template, a highly effective alkaline catalyst is designed. In terms of in situ reassembling, the NiF2 template can be transformed into nickel hydroxide (Ni(OH)2) in hydrogen evolution reaction (HER) and nickel oxyhydroxide (NiOOH) in oxygen evolution reaction (OER), respectively, after only 100 CV cycles, on account of the rapid ion exchange of F− and OH− in an electrochemical environment. Due to the presence of nanocatalytic units, abundant lattice defects, and porous large specific surface structures caused by the reconstruction, it only takes low overpotentials of 57 mV for HER and 228 mV for OER (@10 mA cm−2), with outstanding stability up to 15 d (@100 mA cm−2). Consequently, only a low cell voltage of 1.53 V (@10 mA cm−2) is needed for overall water splitting, superior to commercial noble metal catalysts as benchmarks. Meanwhile, it can output stable current densities of 10, 100, and 500 mA cm−2 approaching 10 d under constant cell voltages of 1.55, 2.0, and 2.5 V, respectively.

Surfactant Intercalation in Li-Al-Based Binary and Ternary Layered Double Hydroxides by the Microwave-Assisted Rapid Ion-Exchange Process and Its Application in Iodine Adsorption

Recognizing the extreme speeds of reactions with microwaves, anionic forms of surfactants (sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS)) have been intercalated successfully by ion-exchange reactions in binary Li-Al and ternary Li-M-Al (M = Mg, Co, Ni, Cu, and Zn) layered double hydroxide (LDH) systems with the aid of microwaves. The samples have been characterized extensively. The basal spacings of 28.2 and 30.4 Å have been estimated for Li-Al-DS and Li-Al-DBS LDH samples, respectively, suggesting a perpendicular arrangement of DS− and DBS− anions in the interlayer space. The characteristic vibration bands of both LDH and the surfactant (DS− and DBS−) in the FTIR spectra confirmed the binding mode of surfactant molecules within the interlayers. DS−-intercalated Li-Al LDH showed lower thermal stability than the DBS−-intercalated sample. The nitrate-intercalated Li-M-Al (M = Mg, Co, Ni, Cu, and Zn) LDHs were ion-exchanged with SDS and SDBS to yield DS−-and DBS−-intercalated systems. The expanded basal spacings and a change in crystallite morphology confirmed the vertical intercalation of DS− and DBS− in Li-M-Al LDHs. ICP-AES and elemental analyses determined the metal contents and the surfactant content. FTIR spectra of intercalated samples confirmed the surfactant’s presence in the interlayer. The presence of Co, Ni, and Cu in Li-M-Al LDHs has been confirmed from UV-visible spectra. The Li-Al-DBS sample adsorbed iodine efficiently from methanol solutions, and the Langmuir model could explain the adsorption data in a better way. The adsorption followed pseudo-second-order kinetics.

Single Image Capture of Bioactive Ion Crosstalk within Inter-Organelle Membrane Contacts at Nanometer Resolution.

Rapid bioactive ion exchange is a form of communication that regulates a wide range of biological processes. Despite advances in super-resolution optical microscopy, visualizing ion exchange remains challenging due to the extremely fast nature of these events. Here, a "converting a dynamic event into a static image construction" (CDtSC) strategy is developed that uses the color transformation of a single dichromatic molecular probe to visualize bioactive ion inter-organelle exchange in live cells. As a proof of concept, a reactive sulfur species (RSS) is analyzed at the mitochondria-lysosome contact sites (MLCs). A non-toxic and sensitive probe based on coumarin-hemicyanine structure is designed that responds to RSS localized in both mitochondria and lysosomes while fluorescing different colors. Using this probe, RSS give-and-take at MLCs is visualized, thus providing the first evidence that RSS is involved in inter-organelle contacts and communication. Taken together, the CDtSC provides a strategy to visualize and analyze rapid inter-organelle ion exchange events in live cells at nanometer resolution.

Lanthanides adsorption on metal-organic framework: Experimental insight and spectroscopic evidence

Herein, lanthanides (Samarium: Sm, Lanthanum: La, and Erbium: Er) adsorption mechanism over copper trimesate metal-organic framework (Cu-BTC MOF) was studied. The MOF crystallized as [Cu(HBTC)(H2O)3] and [Cu3(BTC)2] with a rod-like structure and abundant free COOH groups. The Langmuir adsorption capacity of 1007.1, 656.5, and 410.5 mg g−1 was recorded for Sm, La, and Er, respectively. The adsorption process was driven by rapid ion exchange with crystal structure transformation in the first hour of mixing, mediated by the surface ion-exchange phenomenon and free COOH groups. After 1 h, the process was driven by a slow ion-exchange mechanism where Ln ions drifted internally, and Cu ions moved out towards the surface. Among the three lanthanides studied, Er/Cu-BTC system was more sensitive to structural reorganization with the increasing Ln/Cu ratio. The work reported here is one of the first detailed accounts of the Ln-adsorption process in MOFs.

Ozone-activated CNTs to induce uniform coating of MnO2 as high-performance supercapacitor electrodes

Carbon nanotube (CNT), as a promising material to enhance electrical conductivity and ionic diffusivity, plays an indispensable role in improving the electrochemical performance of transition metal oxides. In this work, a novel core-shell structure of MnO2 coating on carbon nanotubes (MnO2@CNT) was successfully synthesized via a simple solvothermal method. The internal porous structure of CNT as core can facilitate the penetration of electrolyte while improving the electrical conductivity. The thin MnO2 nanosheets as shell can simultaneously achieve a large interaction area and rapid ion exchange. Benefitting from the synergistic effects, the MnO2@CNT shows an excellent capacitance of 386 F g−1 at 1 A g−1 with the content of MnO2 about 52 wt.%. In addition, the MnO2@CNT retains nearly 93.6% of its initial capacitance after 5000 cycles, indicating its excellent cycling performance.

Novel layered iron antimony thiostannate adsorbent of K1.61Fe0.04Sb0.03Sn3.1S7 for cesium green recovery from geothermal water

To develop a green and efficient cesium adsorbent with high adsorption capacity, rapid kinetics, and good regeneration performance is a tremendous challenge. In this work, potassium iron antimony thiostannate (PIATS) synthesized by the hydrothermal method was utilized for green recovery cesium from geothermal water for the first time. PIATS showed a high adsorption capacity of 401.23 mg/g, which was much higher than other types of adsorbents at present. Meanwhile, PIATS showed rapid ion exchange kinetics (within 3 min) and broad pH resistance (4–12). More importantly, PIATS still showed excellent selectivity to cesium even in geothermal water containing many other coexisted ions (Kd = 1.96 × 104 mL/g), and the separation factors between Cs+ and the coexisted competing ions were ranged from 462.77 to 963.76. Subsequently, the cesium-laden PIATS could be easily eluted with 0.50 mol/L NaNO3 to achieve rapid desorption (within 10 min). The concentration of Cs+ in the elution was enriched more than 11 times higher than that in the original solution. Furthermore, no organic solvents or other toxic reagents were involved during the whole process. Therefore, the adsorption advantages, excellent enrichment ability, and structural stability of PIATS make it a potential recyclable candidate for green cesium recovery from geothermal water.

Optimisation of preparation of hazelnut shell activated carbon for adsorption of Cr (III)

The aim of this study was the optimisation of the activated carbon (C) production process by dehydration–carbonisation using concentrated sulfuric acid (H2SO4) from hazelnut shells found locally and readily available agricultural waste and the adsorption of chromium (III) (Cr3+) on the activated carbon produced by this method. An adsorption experiment was carried out at conditions of 25°C and initial concentration of 30 mg chromium (III)/l. The optimum process conditions for ensuring maximum adsorption capacity were investigated by means of statistically designed experiments and steepest ascent experiments. The optimum values found were an impregnation ratio of 4.5 ml sulfuric acid/g hazelnut shells, an oven temperature of 50°C, a holding time in the oven of 19.8 h and a maximum adsorption capacity of 14.76 mg chromium (III)/g hazelnut shell activated carbon (HSAC). The surface properties of HSAC were investigated by scanning electron microscopy and Fourier transform infrared spectroscopy and agreed with the outcomes. The adsorption mechanism could be rapid ion exchange and slow chemisorption and/or an outer-sphere complexation at pH 3.5–6.0 during the process.

Lead sorption from aqueous solutions by kaolinite: laboratory experiments

The lead has adverse effects in contamination the aquatic environment, for this reason, a laboratory simulation was conducted using kaolinite collected from the Ga’ara Formation at western Iraq to be considered as a natural sorbent material that can be addressed Pb2+ from the aqueous environments. The Energy-Dispersive X-ray Spectroscopy and atomic absorption spectroscopy clarifying very fine grains and pure phase with a very little quantity of quartz and has a number of active sites for adsorption. The sorption of kaolinite for the Pb2+ has been carefully tested by several designed laboratory experiments. Five lead solutions of different concentrations (25, 50, 75, 100 and 125 ppm) were tested under different values of pH (1.3-9). The best sorption has been recorded at pH 9, with an equilibrium reaction time 40 m and the solid-liquid ration 1.25 gm:50 ml. The sorption reaction is endothermic with two main mechanisms were identified, the rapid ion exchange which gets at the beginning of the reaction during the first 10 m, and ion exchange, which gets slow later due to form ionic complexes

Tracking Ions the Direct Way: Long-Range Li+ Dynamics in the Thio-LISICON Family Li4MCh4 (M = Sn, Ge; Ch = S, Se) as Probed by 7Li NMR Relaxometry and 7Li Spin-Alignment Echo NMR.

Solid electrolytes are key elements for next-generation energy storage systems. To design powerful electrolytes with high ionic conductivity, we need to improve our understanding of the mechanisms that are at the heart of the rapid ion exchange processes in solids. Such an understanding also requires evaluation and testing of methods not routinely used to characterize ion conductors. Here, the ternary Li4MCh4 system (M = Ge, Sn; Ch = Se, S) provides model compounds to study the applicability of 7Li nuclear magnetic resonance (NMR) spin-alignment echo (SAE) spectroscopy to probe slow Li+ exchange processes. Whereas the exact interpretation of conventional spin–lattice relaxation data depends on models, SAE NMR offers a model-independent, direct access to motional correlation rates. Indeed, the jump rates and activation energies deduced from time-domain relaxometry data perfectly agree with results from 7Li SAE NMR. In particular, long-range Li+ diffusion in polycrystalline Li4SnS4 as seen by NMR in a dynamic range covering 6 orders of magnitude is determined by an activation energy of Ea = 0.55 eV and a pre-exponential factor of 3 × 1013 s–1. The variation in Ea and 1/τ0 is related to the LiCh4 volume that changes within the four Li4MCh4 compounds studied. The corresponding volume of Li4SnS4 seems to be close to optimum for Li+ diffusivity.

Dual Li-ion migration channels in an ester-rich copolymer/ionic liquid quasi-solid-state electrolyte for high-performance Li–S batteries

A novel ester-rich copolymer/ionic liquid quasi-solid-state electrolyte (SPE-IL) was designed, and dual Li-ion migration channels (“association–disassociation” with the carbonyl groups and rapid ion exchange with the ionic liquids) were built in it.

Patterning Rainbowlike Amplified Spontaneous Emission Arrays for Full-Color CsPbX3 Quantum Dot Film Displays

Large-area multicolor laser arrays on the nano- to microscale are key components for the development of on-chip nanophotonics and next-generation color display technology, which remain a formidable task owing to the material lattice mismatch and low-resolution patterning techniques. Here, we demonstrated multicolor-amplified spontaneous emission (ASE) arrays on single-chip integration by patterning CsPbX3 (X = Cl, Br, and I) quantum dot films through a rapid vapor-phase halide ion exchange strategy. Stoichiometrically tunable ASEs were achieved across the whole visible spectral range with similar low thresholds. When the multicolor ASE arrays were further miniaturized to microscale, a spatial definition of 12.5 μm could be achieved, corresponding to an image resolution of up to 2030 pixel per inch.

Anchoring CoS on three-dimensional porous rGO thin films as efficient counter electrodes for dye-sensitized solar cells

Rational design of advanced cost-effective counter electrode (CE) is vital for the development of dye-sensitized solar cells (DSSCs). Herein, we report a novel CoS/reduced graphene oxide (CoS/rGO) composite counter electrode via a facile and rapid microwave irradiation plus ion exchange method. CoS nanoparticles are strongly anchored on three-dimensional (3D) porous rGO thin films. Due to positive advantages including high catalytic properties, enhanced active area, and electrical conductivity, the DSSC based on CoS/rGO counter electrode is endowed with a power conversion efficiency (PCE) of 6.86%, superior to that based on sputtered Pt counter electrode (6.50%). Our results indicate that CoS/rGO composite thin film is a low-cost and highly efficient CE for DSSCs.

Mechanistic study on the removal of Cs from contaminated soil by rapid ion exchange in subcritical water

ABSTRACT As a result of the Fukushima nuclear power plant accident in March 2011, massive amounts of soil were contaminated with radioactive Cs. To remediate the contaminated soil, we are developing a desorption technique for removing Cs from soil using subcritical water. In the contaminated soil, the radioactive Cs is stably trapped in the interlayers of the clay minerals, making the use of traditional desorption approaches ineffective. However, we found that rapid ion exchange of Cs with multivalent cations in subcritical water is an effective desorption technique. To understand the mechanism and structural aspects of this process, in situ observations of the soil layer in subcritical water were carried out by high-energy X-ray diffraction together with pair distribution function analysis, and extended X-ray absorption fine structure analysis at SPring-8. Simulated contaminated soil (vermiculite) loaded with non-radioactive Cs+ was packed into a column equipped with observation ports and MgCl2 solution was passed through the column at a fixed flow rate under various conditions. Both the desorption experiments and structural studies indicated that conformational changes of the layer containing Cs+ under subcritical water conditions promoted intercalation of the hydrated Mg and trapped Cs+, which facilitated a rapid ion-exchange reaction of Mg2+ and Cs+.

Template-free synthesis of hierarchical mesoporous carbon: Based on functional coal tar pitches with carboxylation and diketone structures

An efficient and easy template-free method for the preparation of hierarchical porous carbons (HPCs) has been developed using low-priced coal tar pitch (CP) as the starting material. Application of the diketone (-COCO-) radical provides a carbonyl methylene group for polycyclic aromatic hydrocarbons by condensation and produces an effective micro-mesoporous network with a high specific surface area. With the help of controlled Friedel-Crafts reaction and oxidation, carboxyl-functionalized CP is obtained as the stratified porous CP precursor, and the high-temperature decarboxylation (>230°C) helped in generating well-developed micro-mesoporous carbon. The total pore volume of porous carbon of 1277.3 and 1.45 cm 3 g -1 the maximum BET surface area suggests that the rapid electrolyte ion exchange and charge transportability would be better for the electrochemical capacitor.

Rapid and selective removal of Cs+ from water by layered potassium antimony thiostannate

137Cs is radioactive and highly hazardous to human health and the environment and its efficient removal from water is still challenging. In this study, potassium antimony tin sulfide (KATS-2) was synthesized using a hydrothermal method and utilized for the first time for cesium removal from water. KATS-2 showed a high maximum ion exchange capacity (358 mg g−1) and distribution coefficient (1.59 × 105 mL g−1) toward Cs+. In particular, KATS-2 showed rapid ion exchange kinetics and reached the adsorption equilibrium within 5 min with 99% removal efficiency. The adsorption was good at a wide active pH range (1–12) even in extreme alkaline conditions (Kd = 3.26 × 104 mL g−1 at pH 12). The effect of coexisting ions was also investigated, and a high selectivity toward Cs+ was maintained even in artificial seawater (Kd = 3.28 × 103 mL g−1). Powder X-ray diffraction and thermogravimetric analysis demonstrated that KATS-2 was chemically and thermally stable. The results showed that owing to its excellent adsorption performance as well as chemical and thermal stability, KATS-2 is a promising adsorbent for Cs+ removal from contaminated water.

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.