Solubility Of Ions Research Articles

Development and systematic characterization of GelMA/alginate/PEGDMA/xanthan gum hydrogel bioink system for extrusion bioprinting

Gelatin methacryloyl (GelMA)/alginate-based hydrogels have shown great promise in bioprinting, but their printability is limited at room temperature. In this paper, we present our development of a room temperature printable hydrogel bioink by introducing polyethylene glycol dimethacrylate (PEGDMA) and xanthan gum into the GelMA/alginate system. The inclusion of PEGDMA facilitates tuning of the hydrogel's mechanical property, while xanthan gum improves the viscosity of the hydrogel system and allows easy extrusion at room temperature. To fine-tune the mechanical and degradation properties, methacrylated xanthan gum was synthesized and chemically crosslinked to the system. We systematically characterized this hydrogel with attention to printability, strut size, mechanical property, degradation and cytocompatibility, and achieved a broad range of compression modulus (∼10–100 kPa) and degradation profile (100% degradation by 24 h–40% by 2 weeks). Moreover, xanthan gum demonstrated solubility in ionic solutions such as cell culture medium, which is essential for biocompatibility. Live/dead staining showed that cell viability in the printed hydrogels was over 90% for 7 days. Metabolic activity analysis demonstrated excellent cell proliferation and survival within 4 weeks of incubation. In summary, the newly developed hydrogel system has demonstrated distinct features including extrusion printability, widely tunable mechanical property and degradation, ionic solubility, and cytocompatibility. It offers great flexibility in bioprinting and tissue engineering.

A Shuttle-Free Solid-State Cu-Li Battery Based on a Sandwich-Structured Electrolyte.

Cu-Li batteries leveraging the two-electron redox property of Cu can offer high energy density and low cost. However, Cu-Li batteries are plagued by limited solubility and a shuttle effect of Cu ions in traditional electrolytes, which leads to low energy density and poor cycling stability. In this work, we rationally design a solid-state sandwich electrolyte for solid-state Cu-Li batteries, in which a deep-eutectic-solvent gel with high Cu-ion solubility is devised as a Cu-ion reservoir while a ceramic Li1.4 Al0.4 Ti1.6 (PO4 )3 interlayer is used to block Cu-ion crossover. Because of the high ionic conductivity (0.55 mS cm-1 at 25 °C), wide electrochemical window (>4.5 V vs. Li+ /Li), and high Cu ion solubility of solid-state sandwich electrolyte, a solid-state Cu-Li battery demonstrates a high energy density of 1 485 Wh kgCu -1 and long-term cyclability with 97 % capacity retention over 120 cycles. The present study lays the groundwork for future research into low-cost solid-state Cu-Li batteries.

A Shuttle‐Free Solid‐State Cu−Li Battery Based on a Sandwich‐Structured Electrolyte

AbstractCu−Li batteries leveraging the two‐electron redox property of Cu can offer high energy density and low cost. However, Cu−Li batteries are plagued by limited solubility and a shuttle effect of Cu ions in traditional electrolytes, which leads to low energy density and poor cycling stability. In this work, we rationally design a solid‐state sandwich electrolyte for solid‐state Cu−Li batteries, in which a deep‐eutectic‐solvent gel with high Cu‐ion solubility is devised as a Cu‐ion reservoir while a ceramic Li1.4Al0.4Ti1.6(PO4)3 interlayer is used to block Cu‐ion crossover. Because of the high ionic conductivity (0.55 mS cm−1 at 25 °C), wide electrochemical window (>4.5 V vs. Li+/Li), and high Cu ion solubility of solid‐state sandwich electrolyte, a solid‐state Cu−Li battery demonstrates a high energy density of 1 485 Wh kgCu−1and long‐term cyclability with 97 % capacity retention over 120 cycles. The present study lays the groundwork for future research into low‐cost solid‐state Cu−Li batteries.

Direct electroseparation of zinc from zinc sulfide in eco-friendly deep eutectic solvent: Highlighting the role of malonic acid

Zinc sulfide (ZnS), one of the main ingredients of zinc ore and emerging materials, partly processes environmental risk. Deep eutectic solvents (DESs) are green solvents to efficiently separate metals with less emission. In this study, a novel route for direct electroseparation of Zn from ZnS in eco-friendly choline chloride-urea DES with the addition of malonic acid (MA) is studied for the first time. The role of MA and the reduction behavior of Zn(II) are systematically analyzed by cyclic voltammetry. The reduction of Zn(II) is quasi-reversible and follows one-step two-electron transfer process. Pure Zn with nanostructure is obtained with the current efficiency of 86.5 % and energy consumption of 2621.8 kW·h·t−1 at the optimized parameters of 10 mA·cm−2, 353 K and 100 mM·L-1 ZnS. Mechanisms analyses indicate that in the presence of 60 mM·L-1 MA, besides [ZnCl−3]- and [ZnCl−5]3-, some ZnS are dissolved to form stable [Zn(MA)2-Cl−2]4-, [Zn(MA)2-Cl-]3- and other MA based ligands, which causes a higher Zn ion solubility of 0.13 mol·L-1 and may promote the subsequent electroseparation of ZnS. Results from this study are expected to propose a simplified route to directly separate Zn from ZnS without oxidation pretreatment to achieve hazardous waste minimization.

Influence of CaF2 addition on structure and luminescence properties of the Na2O–CaO–SiO2–Al2O3–ZnO–P2O5 glass co-doped with Ce3+/Yb3+

Na2O–CaO–SiO2–Al2O3–ZnO–P2O5–CaF2 glasses co-doped with Ce3+/Yb3+ ions were obtained. The effects of added CaF2 on the glass structure, stability, and luminescence properties of the fluorosilicate glasses were studied. The research results show that the introduction of fluoride ions can reduce the crystallization peak temperature of the glass and increase the crystallization tendency of the glass. Structural analysis shows that the network breaking effect of F− ion is more obvious after CaF2 replaces CaO, and more glass network terminator sites are produced, raising the molar volume of the prepared glasses. The results of transmission spectra reveal that with the rise of CaF2 doping content, the UV cut-off wavelength appears blue-shift, which can be explained by the change of optical alkalinity of the prepared glass. Analysis of fluorescence performance shows that the intensity and inhomogeneous broadening of the emission peaks displays an increasing trend, which might be related to the decrease of glass phonon energy and the increase of rare-earth ion solubility. The above results indicate that the prepared Na2O–CaO–SiO2–Al2O3–ZnO–P2O5–CaF2 glasses co-doped with Ce3+/Yb3+ ions have potential applications for solar cells.

Structural, Magnetic Evaluation of Neodymium Doped Nickel-Zinc-Iron Soft Spinel Metal Oxides for Humidity Sensor Applications

A series of combustion assisted low-temperature neodymium substituted Ni–Zn–Fe (NZF) nanoparticles were synthesized to unravel the impact on functional behavior of NZF due to the presence of larger Nd ions. The nanopowders were structurally evaluated with X-ray diffraction and infrared spectroscopy measurements without further heat treatment. X-ray diffraction clearly evident the monophasic nature of all the samples and solubility of Nd ions in the spinel unit cell. The average crystallite size from Scherrer and Williamson–Hall method are found below 30 and 20 nm for all the samples, respectively. A distinct shift was observed in most intense peak (3 1 1) suggesting the adjustment among interionic distances to accommodate larger ions. The microstructure, morphology was evaluated from SEM measurements. Magnetic measurements at room temperature show a dramatic change in magnetization, improvement in soft-magnetic nature with low coercivity behavior with Nd substitution. The variation of resistance with respect to humidity conditions suggested that these materials are potentially suitable for resistive humidity sensor applications.

A Solid/Liquid High-Energy-Density Storage Concept for Redox Flow Batteries and Its Demonstration in an H2-V System

Redox flow batteries (RFBs) are ideal for large-scale, long-duration energy storage applications. However, the limited solubility of most ions and compounds in aqueous and non-aqueous solvents (1M–1.5 M) restricts their use in the days-energy storage scenario, which necessitates a large volume of solution in the numerous tanks and the vast floorspace for these tanks, making the RFB systems costly. To resolve the low energy storage density issue, this work presents a novel way in which the reactants and products are stored in both solid and soluble forms and only the liquid with soluble ions is circulated through the batteries. Storing the active ions in solid form can greatly increase the storage energy density of the system. With a solid to liquid storage ratio of 2:1, for example, the energy density of the electrolyte of vanadium sulfate (VOSO4), an active compound used in the all-vanadium RFB, can be increased from 40 Ah l−1 to 163 Ah l−1 (>4X), allowing an existing 6-h RFB system to become a 24-h system with minimal modifications. To show how the concept works, an H2-V flow battery with a solid/liquid storage system is used, and its successful demonstration validates the solid-liquid storage concept.

A new operando surface restructuring pathway via ion-pairing of catalyst and electrolyte for water oxidation

The highly efficient and stable electrolysis needs the rational control of the catalytically active interface during the reactions. Here we report a new operando surface restructuring pathway activated by pairing catalyst and electrolyte ions. Using SrCoO3-δ-based perovskites as model catalysts, we unveil the critical role of matching the catalyst properties with the electrolyte conditions in modulating catalyst ion leaching and steering surface restructuring processes toward efficient oxygen evolution reaction catalysis in both pH-neutral and alkaline electrolytes. Our results regarding multiple perovskites show that the catalyst ion leaching is controlled by catalyst ion solubility and anions of the electrolyte. Only when the electrolyte cations are smaller than catalyst's leaching cations, the formation of an outer amorphous shell can be triggered via backfilling electrolyte cations into the cationic vacancy at the catalyst surface under electrochemical polarization. Consequently, the current density of reconstructed SrCoO3-δ is increased by 21 folds compared to the pristine SrCoO3-δ at 1.75 V vs reversible hydrogen electrode and outperforms the benchmark IrO2 by 2.1 folds and most state-of-the-art electrocatalysts in the pH-neutral electrolyte. Our work could be a starting point to rationally control the electrocatalyst surface restructuring via matching the compositional chemistry of the catalyst with the electrolyte properties.

Antiferromagnet-Ferromagnet Transition in Fe1-xCuxNbO4.

Iron niobates, pure and substituted with copper (Fe1-xCuxNbO4 with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample. The analysis of the magnetic properties showed that the antiferromagnetic-ferromagnetic transition was caused by the insertion of Cu2+ ions into the FeNbO4 structure. The pure FeNbO4 structure presented an antiferromagnetic ordering state, with a Néel temperature of approximately 36.81K. The increase in substitution promoted a change in the magnetic ordering, with the state passing to a weak ferromagnetic order with a transition temperature (Tc) higher than the ambient temperature. The origin of the ferromagnetic ordering could be attributed to the increase in super-exchange interactions between Fe/Cu ions in the Cu2+-O-Fe3+ chains and the formation of bound magnetic polarons in the oxygen vacancies.

New Developments in the High-Energy-Density Solid-Liquid Storage Technology for Redox Flow Batteries

The environmental impact of the use of fossil fuels for energy can be reduced if electricity, which represents one-third of all energy uses, can be generated totally from renewable/sustainable sources such as wind and solar. However, this is only possible if cost-effective long-duration storage technologies are available to allow the highly variable and unpredictable wind and solar energy sources to become reliable baseline energy sources like coal, nuclear or natural gases. Redox flow battery (RFB) energy storage systems are highly suitable for this large-scale, long-duration storage application because while their power output scales with the size of the battery, their energy content resides in the amount of active materials that are stored in external tanks and can be easily scaled up for longer duration.1 The conventional redox flow batteries store electrical energy in the form of some aqueous or non-aqueous soluble ions or compounds in the electrolyte solution. Because of the low solubility (< 2M) of most ions and compounds in aqueous and non-aqueous solvents, these redox flow battery systems have low energy density.2–4 For example, the commercialized all-vanadium RFB system has an average energy density of 20 Wh/kg while that of the lithium-ion battery system is 100-265 Wh/kg.5 To store enough energy for 3-5 days in these RFBs requires a very large volume of solution in a large number of tanks, making these RFB systems expensive due to the cost of tanks and the fluid distribution system and floor space. Our group recently developed a new storage approach that can greatly increase the energy storage density while still enabling the flow battery concept.6 In this approach, the reactants are stored as both soluble ions and their undissolved solid forms and only the liquid containing the soluble ions is circulated through the batteries. This approach potentially enables >4X increase in the storage energy density. This technology was recently demonstrated in a hydrogen-vanadium (VI/V) system, and new test results and findings in this area will be presented in this talk.References H. Zhang, W. Lu, and X. Li, Electrochemical Energy Reviews, 1–15 (2019).D. G. Kwabi et al., Joule, 2, 1894–1906 (2018).M. Wu, T. Zhao, H. Jiang, Y. Zeng, and Y. Ren, Journal of Power Sources, 355, 62–68 (2017).C. Ding, H. Zhang, X. Li, T. Liu, and F. Xing, The Journal of Physical Chemistry Letters, 4, 1281–1294 (2013).A. Manthiram, ACS Central Science, 3, 1063–1069 (2017).Y. Li and T.V. Nguyen, “A Solid-Liquid High-Energy-Density Storage Concept for Redox Flow Batteries and Its Demonstration in an H2-V System,” Paper ID APEN-MIT-2021_023, Applied Energy Symposium: MIT A+B, Aug. 11-13, 2021, Cambridge, MA, USA.

(Digital Presentation) Electrochemical Behavior of Ionic Liquid Modified of Lithium Bis(fluorosulfonyl)Imide Based Electrolyte for Lithium-Ion Batteries

The high efficient energy storage, lithium-ion batteries (LIBs) is accounted as one of the most important storage devices to facilitate the transition of renewable energy conversion. The electrolyte component is the most important in deciding the capacity of LIBs. Lithium bis(fluorosulfonyl)imide (LiFSI) is recently considered as promising conducting electrolyte salt for LIBs because it shows enabling high voltage, high energy density, long cycle life, and accelerates the fast-charging Li-ion batteries. Generally, Additionally, LiFSI and LiPF6 based electrolyte are used in the most of commercial LIBs. Last few years, LiFSI is regarded as an alternative electrolyte to the classical LiFP6 due to its high ionic conductivity, good thermal stability, and HF free nature. In this work, the controlled mixing of ionic liquids (ILs) (imidazolium salts and pyridinium salts) in LiFSI electrolyte was carried out to enhance the ionic conductivity, thermal stability, viscosity, and solubility in organic solvents. The ILs modified LiFSI electrolyte was prepared by adding a constant 1.0 M LiFSI and varying the concentration of ILs from 5 to 20% volume in trimethyl phosphate (TMP). After the modification by ILs, the ionic conductivity of LiFSI electrolyte (10.623 mS/cm) was considerably increased as compared to LiFSI only. The flammability test of electrolyte revealed that ILs modified LiFSI electrolyte was non-flammable, indicating excellent stability in any circumstances. The prepared ILs modified LiFSI electrolyte was used to fabricate coin cell LIBs using double-coated side electrodes (both CMS graphite/Li-NCM (5:2:3) and CMS graphite/LiFePO4). From GCD analysis, the fabricated LIBs with ILs modified LiFSI electrolyte showed a significant improvement in the charging/discharging ability as compared to commercial LIBs with LiPF6 electrolyte. This study manifests that the modification of LiFSI by novel ILs would be promising to achieve highly efficient liquid electrolytes for high performance LIBs.

Alkalizing Properties of Six Calcium-Silicate Endodontic Biomaterials.

Introduction: Calcium silicate-based cements (CSC), are self-setting hydraulic biomaterials widely used for reparative procedures in dentistry and endodontics. These materials possess physical properties, such as ion release, porosity, solubility, and radiopacity. Their biological properties are connected to their alkalizing activity and calcium release capacity. Materials and Methods: Six calcium silicate-based materials were selected for this study: TheraCal LC (Bisco Inc., Schaumburg, IL, USA), MTA Plus (PrevestDenpro, Jammu, India Avalon Biomed Inc., Bradenton, FL, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), RetroMTA (BioMTA, Seoul, Korea), MTA Flow (Ultradent Products, Inc., South Jordan, UT, USA), and OrthoMTA (BioMTA, Seoul, Korea). The pH was analyzed immediately after immersion (baseline) and after 1 h, 3 h, 1 day, 2 days, 3 days, 1 week, 2 weeks, 3 weeks, and 1 year with a pH meter, previously calibrated with solutions of known pH. All testing materials had alkaline pH. Results: Analysis of the tested materials showed statistically significant differences in terms of pH changes as a function of the time showed a gradual rise in the pH of all materials. Conclusions: All tested materials exhibited continuous hydroxyl ion release resulting in a rise in pH until the end of time of experience.

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by 17O-Excess Signatures.

Numerical models have been developed to elucidate air pollution caused by sulfate aerosols (SO42–). However, typical models generally underestimate SO42–, and oxidation processes have not been validated. This study improves the modeling of SO42– formation processes using the mass-independent oxygen isotopic composition [17O-excess; Δ17O(SO42–)], which reflects pathways from sulfur dioxide (SO2) to SO42–, at the background site in Japan throughout 2015. The standard setting in the Community Multiscale Air Quality (CMAQ) model captured SO42– concentration, whereas Δ17O(SO42–) was underestimated, suggesting that oxidation processes were not correctly represented. The dust inline calculation improved Δ17O(SO42–) because dust-derived increases in cloud-water pH promoted acidity-driven SO42– production, but Δ17O(SO42–) was still overestimated during winter as a result. Increasing solubilities of the transition-metal ions, such as iron, which are a highly uncertain modeling parameter, decreased the overestimated Δ17O(SO42–) in winter. Thus, dust and high metal solubility are essential factors for SO42– formation in the region downstream of China. It was estimated that the remaining mismatch of Δ17O(SO42–) between the observation and model can be explained by the proposed SO42– formation mechanisms in Chinese pollution. These accurately modeled SO42– formation mechanisms validated by Δ17O(SO42–) will contribute to emission regulation strategies required for better air quality and precise climate change predictions over East Asia.

Study of Quaternary Ammonium Additives towards High-Rate Zinc Deposition and Dissolution Cycling for Application in Zinc-Based Rechargeable Batteries

Aqueous zinc-based rechargeable batteries, such as Zn-Ni and Zn-Air, have been increasingly re-investigated over the last decade due to the abundant and inexpensive nature of zinc, the high solubility of zinc ions, and rapid kinetics and most negative standard potential of the Zn(II)/Zn redox couple in aqueous media. However, the overwhelming challenge that has prevented the implementation of next-generation Zn batteries lies in their poor rechargeability—flowing electrolytes have proven to be of benefit to zinc deposition and dissolution cycling, but the rapid zinc deposition–dissolution at practical current densities of 100 mA cm2 or over is still questionable. Herein, we demonstrated that applying an optimal concentration of quaternary ammonium electrolyte additives with carefully selected cations’ alkyl groups can effectively improve the high-rate zinc cycling performance at 100 mA cm2/20 mAh cm2. The resultant additives significantly reduced the initial coulombic efficiency loss to only 1.11% with coulombic efficiency decay rate of 0.79% per cycle, which is less than a quarter of the benchmark of 6.25% and 3.75% per cycle for no additives.

Extraction of alumina from low-grade kaolin in the presence of lime and NaOH via multi-stage hydrothermal process

Kaolinite as an aluminum-rich clay mineral is widely distributed in kaolin, coal gangue and mill tailings, etc. Herein, alumina extraction from the low-grade kaolin was explored via multi-stage hydrothermal process in the presence of NaOH and lime. In single stage, maximum alumina leaching ratio was found to be 33.64% in the presence of 20 g/L NaOH, 180 °C leaching temperature, 2 h leaching time and CaO/SiO2 molar ratio of 0.7. The formation of zeolites due to limited solubility of aluminate ions resulted in the low alumina leaching ratio. Then, a multi-stage hydrothermal process was proposed to improve the alumina leaching, with each stage being carried out at 180 °C for 0.1 h. The cumulative alumina leaching ratio attained 72.09% after three-stage hydrothermal process; after desilication, the lixivium was used for preparing pseudo-boehmite via carbonation. Conclusively, the multi-stage hydrothermal process achieved the efficient extraction of alumina from kaolinite and presented great potential in improving the economic value of low-grade kaolin.

Rare earth tungstate high-entropy ceramic powders containing holmium with broad-spectrum antibacterial and antiviral activity

A2W3O12-type (A=La, Sm, Eu, Gd, RE) rare earth tungstate high-entropy ceramic powder with a positively charged surface was fabricated by a high-temperature solid-phase method, and its antibacterial and antiviral properties were evaluated for the first time. Changes in the antibacterial and antiviral activity and ionic solubility of these compounds induced by changing the RE element at the A-position were investigated. The A2W3O12 high-entropy ceramic powder was a stable surface antibacterial material. Its antimicrobial properties are not affected by light and environmental acids and bases. The (La0.2Sm0.2Eu0.2Gd0.2Ho0.2)2W3O12 high-entropy ceramic powder had the best antibacterial performance in the absence of light, and the killing rate was more than 99.9% for both Staphylococcus aureus and Escherichia coli. On this basis, the animal viruses H1N1 influenza virus (enveloped) and EV71 enterovirus (nonenveloped) were selected for antiviral testing, and the survival rate of both viruses decreased by more than 99% within 2 h. The powder was evaluated for ion solubilization under acidic and alkaline service conditions, showing low ion solubilization and superior environmental suitability.

Er:YAG/Yb:YAG nanopowders‐derived Er/Yb co‐doped yttrium aluminosilicate (YAS) fibers fabricated by UV‐curable nanocomposites for 1.5‐µm single‐frequency fiber lasers

AbstractThe rare‐earth (RE)‐doped yttrium aluminosilicate (YAS) glass fibers have demonstrated their unique advantages in single‐frequency lasers due to their high solubility of RE ions and high gain per unit length. However, the RE‐doped YAS fiber is usually fabricated by RE:YAG crystal or ceramic rods and melting‐in‐tube method, which depend heavily on RE:YAG crystal or ceramic rods and, thus, cannot adjust the fiber compositions effectively; there is little research on the multiple RE ions co‐doped YAS fiber deriving from RE:YAG crystal or ceramic rods. In present work, we developed a novel method to fabricate Er/Yb co‐doped YAS fibers efficiently. The Er:YAG and Yb:YAG nanopowders were fabricated by the coprecipitation method, and then the nanopowders were dispersed into liquid organic resin to form a novel UV‐curable nanocomposite, after curing, debinding, purifying, and drawing process, an Er/Yb co‐doped YAS fibers was fabricated, the absorption coefficients of the fiber was measured to be 17 dB/cm at 976 nm (2F7/2ground level to2F5/2level of Yb and4I15/2ground level to4I11/2level of Er) and 3.2 dB/cm at 1530 nm (4I15/2ground level to the high states of4I13/2of Er). A 1.5‐µm single‐frequency laser was constructed with the 2‐cm Er/Yb co‐doped YAS fiber. The longitudinal mode spacing was calculated to be 2.2 GHz with an effective cavity length of 4.5 cm, and the spectral signal‐to‐noise ratio was higher than 60 dB. To the best of our knowledge, it is the first time that Er/Yb co‐doped YAS fibers are fabricated using the UV‐curable nanocomposites. It indicates that this proposed technology is critical for the fabrication of various types of RE ions co‐doped YAS fibers and their applications in single‐frequency fiber lasers.

Coupling between γ-irradiation and synchrotron-radiation-based XAFS techniques for studying Mn-doped ZnO nanoparticles.

γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33-41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn-Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1-xMnxO NPs are recommended as optimized candidates for showing the diversity of the applications.

Investigation of scale inhibition effect and mechanism of S-HGMF in the clean recirculating cooling water system

The formation of scales in a recirculating water system is a common problem in industrial water treatment; it seriously affects the production in various industries and pollutes the environment. Although conventional scale inhibition methods are effective, they are expensive and harm the environment. Herein, an advanced method is proposed to solve the scaling issue in recirculating cooling water systems using the superconducting high-gradient magnetic field (S-HGMF) treatment. The scale inhibition performance could be improved by changing the magnetic flux density, operation time, and flow rate. The results showed that S-HGMF could increase the number of hydrogen bonds in the recirculating cooling water, enhance molecular interaction, increase the thickness of the ion hydration shell, reduce the nucleation rate, stabilize the water quality, improve the solubility of scale-forming ions, and inhibit scale formation. The scale inhibition performance reached 8.10%. Interestingly, S-HGMF had a memory effect in that it could maintain the scale inhibition effect for some period after treatment completion. Moreover, S-HGMF changed the crystal structure of the scale and promoted the transformation of the scale to a metastable phase. Ultimately, calcite was transformed to aragonite to reduce the precipitation of hard scale (calcite), achieving the purpose of scale inhibition. As a physical method, the application of S-HGMF to inhibit scaling has great potential for industrial applications.

Closed-loop cobalt recycling from spent lithium-ion batteries based on a deep eutectic solvent (DES) with easy solvent recovery

Efficient recycling technology for the rapid growth of spent lithium-ion batteries (LIBs) is essential to tackle the resources and environmental crisis. Hydrometallurgical approach has attracted extensive research due to its potential to reduce the consumption of energy and threat to the environment. However, the simultaneous realization of green, efficient and closed-loop recycling is still challenging. Herein, we report a closed-loop and highly efficient approach to recycle lithium cobalt oxide from spent LIBs based on a choline chloride:oxalic acid (ChCl:OA) type deep eutectic solvent (DES). An ultrafast leaching process is observed at 180 °C for 10 s with no observable residues. The energy barrier during leaching is calculated to be 113.9 kJ/mol. Noteworthy, the solubility of cobalt ions can be reversibly tuned by simply adding/evaporating deionized water, thus avoiding the addition of precipitant and enabling the easy recovery of the leaching solvent for realizing a closed-loop recycling process. The simultaneous realization of high efficiency, green and closed-loop process is expected to push the DES into practical application for recycling the electrodes of LIBs.