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The rapid progress of urbanization and industrialization has led to the accumulation of large amounts of metal ions in the environment. These metal ions are adsorbed onto the negatively charged surfaces of clay particles, altering the total surface charge, double-layer thickness, and chemical bonds between the particles, which in turn affects the interactions between them. This causes changes in the microstructure, such as particle rearrangement and pore morphology adjustments, ultimately altering the mechanical behavior of the soil and reducing its stability. This study explores the effects of four common metal ions, including monovalent alkali metal ions (Na+, K+) and divalent heavy metal ions (Pb2+, Zn2+), with a focus on how ion valence and concentration impact the soil's microstructure and mechanical properties. Microstructural tests show that metal ion incorporation reduces particle size, increases clay content, and transforms the structure from layered to honeycomb-like. Small pores decrease while large pores dominate, reducing the specific surface area and pore volume, while the average pore size increases. Although cation exchange capacity decreases, cation adsorption density per unit surface area increases. Monovalent ions primarily disperse the soil structure, while divalent ions induce coagulation. Macro-mechanical tests reveal that metal ion contamination reduces porosity under loading, with compressibility rises as the ion concentration increases. Soils contaminated with alkali metal ions shows higher compression coefficients at all loads, while heavy metal ions cause higher compression under lower loads. Shear strength, the internal friction angle, and cohesion in metal-ion-contaminated clay decrease compared to uncontaminated field-state clay, with greater declines at higher ion concentrations. The Micropore Morphology Index and hydro-pore structural parameter effectively characterize both micro- and macrostructural properties, establishing a quantitative relationship between HPSP and the engineering properties of metal-ion-contaminated clay. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A density functional theory method was employed to conduct theoretical calculations on the pyrolysis reaction pathways of lignin monomer model compounds with an aldehyde or carboxyl group under the catalytic effect of alkali metal ions Na+ and K+, exploring their influence on the formation of the small molecular gaseous products CO and CO2. The results indicate that Na+ and K+ can easily bind with the oxygen-containing functional groups of the lignin monomer model compounds to form stable and low-energy complexes. Except for benzaldehyde and p-hydroxybenzaldehyde, Na+ and K+ can facilitate the decarbonylation reactions of other benzaldehyde-based and phenylacetaldehyde-based lignin monomer model compounds during the pyrolysis process, thereby enhancing the generation of CO. When the characteristic functional groups on the benzene rings of benzaldehyde-based and phenylacetaldehyde-based lignin monomer model compounds are the same, the phenylacetaldehyde-based ones are more prone to undergo decarbonylation than the benzaldehyde-based ones. Additionally, both Na+ and K+ can inhibit the decarboxylation reactions of benzoic acid-based and phenylacetic acid-based lignin monomer model compounds, thereby restraining the formation of CO2. When the characteristic functional groups on the benzene rings of benzoic acid-based and phenylacetic acid-based lignin monomer model compounds are the same, the phenylacetic acid-based ones are more difficult to undergo decarboxylation than the benzoic acid-based ones. [ABSTRACT FROM AUTHOR]

Natural products include inorganic as well as organic compounds. Living organisms face constant challenges in acquiring essential metal ions and getting rid of non-essential ones with toxic actions. They employ an extracellular biochemistry in these tasks and use it to engage in a chemical warfare against invaders and competitors by either increasing or decreasing the availability of metal ions for maintaining their welfare in aquatic or terrestrial ecological niches. To control mutualistic, cambialistic or parasitic symbiosis with other organisms they use a remarkably rich suite of secreted bioactive molecules with ligand donor atoms for metal binding. This overview discusses the interactions of these extracellular natural products with a multitude of metal ions in the periodic system of the elements. It focuses mainly on metallophores and metal ionophores secreted from bacteria, fungi, and plants, but metal-carrying cofactors and other chelating agents will also be mentioned in the context of related functions and with an intent to categorize. The intracellular fate of the metal ions and the controlled pathways for the biosynthesis, secretion, uptake, biodegradation or recycling of the secreted natural products that interact with metal ions will not be covered. Metallophores make extracellular metal ions available via delivery to specific transporters and unavailable to competing organisms, especially pathogens, though some invaders have developed ways to compete efficiently for metal ions. The classic concept of siderophores, carriers of iron(III) ions, is extended here to specific and broad-band metallophores for metal ions such as copper (chalkophores), zinc (zincophores), and yet others. Metal ionophores, in contrast, transport metal ions through biological membranes. There is a wide variety of chemical structures for either metallophores or metal ionophores. Together with physicochemical investigations of metal complexation und conditions mimicking the natural environment, “omics” mining and mapping the diversity of chemotypes is an on-going effort with analytic, genetic, and bioinformatic tools and comes together in defining the metallometabolome, which combines the metabolome and the metallome. Investigations are highly multidisciplinary, include an important, but academically infrequently crossed bridge between the biosciences (biochemistry) and the earth sciences (geochemistry), define significant applications in the pharmaceutical/medical sciences regarding immune modulation and the control of virulence at the host-pathogen interface, and have implications for the nutritional/toxicological and environmental/ecological sciences. [ABSTRACT FROM AUTHOR]

This study investigates the genesis of analcite in black shale from continental lakes and its implications for hydrocarbon enrichment, with a case study of the Permian Pingdiquan Formation in the Junggar Basin, Xinjiang, China. As an alkaline mineral, analcite is extensively developed in China's lacustrine black shale hydrocarbon source rocks and is linked to hydrocarbon distribution. However, the mechanisms of its formation and its impact on hydrocarbon generation and accumulation remain insufficiently understood. This paper employs a multi-analytical approach, including petrological observations, geochemical analysis, and X-ray diffraction, to characterize analcite and its association with hydrocarbon source rocks. The study identifies a hydrothermal sedimentary origin for analcite, suggesting that it forms under conditions of alkaline lake water and volcanic activity, which are conducive to organic matter enrichment. The analcite content in the studied samples exhibits a significant variation, with higher contents associated with hydrocarbon accumulation zones, suggesting its role in hydrocarbon generation and accumulation. This paper reports that analcite-bearing rocks display characteristics of high-quality reservoirs, enhancing the permeability and porosity of the rock, which is essential for hydrocarbon storage and migration. In conclusion, this paper underscores the importance of analcite as a key mineral indicator for hydrocarbon potential in black shale formations and provides valuable insights for further geological and hydrocarbon exploration in similar settings. [ABSTRACT FROM AUTHOR]

The study investigated the effects and mechanisms of clay content, emulsion water content, pH, and metal cations on clay-crude oil emulsions. The results indicate the following: 1) At a water content of 50 V/V%, montmorillonite can form emulsions with crude oil at different concentrations, with the highest stability observed at 5 wt% content. In contrast, chlorite, illite, and kaolinite cannot form emulsions at low concentrations. 2) Under acidic conditions, montmorillonite, illite, and chlorite cannot form emulsions with crude oil, or the emulsions are highly unstable. However, kaolinite forms more stable emulsions under acidic conditions. In alkaline environments, emulsions formed by all clay minerals exhibit increased stability. 3) The order of the effectiveness of different metal cations in reducing the stability of montmorillonite-crude oil emulsions is K+ > Na+ > Mg2+ > Ca2+, while for chlorite, illite, and kaolinite, it is Mg2+ > Ca2+ > K+ > Na+. 4) The factors that influence the stability of clay-crude oil emulsions are the arrangement of clay particles in water and the dispersion capability of clay particles in water. The most significant influencing factor is the arrangement of clay particles in water. [ABSTRACT FROM AUTHOR]

Yeasts present in mangrove sediments were found to play an important role in detrital food web, nutrient cycling, decomposition and biodegradation. They produce hydrolytic enzymes and secondary metabolites which have formidable industrial, biotechnological and bioremediation properties. Since the mangrove sediments experience extreme environmental circumstances, the yeast and the enzymes produced from them can also withstand such utmost conditions. This makes mangrove sediment yeasts the best source for the production of industrially and biotechnologically important enzymes. Yeasts that can produce extracellular lipases were screened and isolated from the mangrove sediments of Kerala coast. Lipases were isolated and purified from two selected strains identified as Candida tropicalis (VPY3) and Diutina mesorugosa (VPY42). The final purification folds of C.tropicalis and D.mesorugosa lipases were calculated to be 5.6% and 4.6% and final specific activities were 2.643 U/mg and 2.662 U/mg respectively. The molecular weights of the purified lipases were estimated by SDS-PAGE to be ~50kDa for Candida tropicalis and ~59kDa for D.mesorugosa. The optimum incubation time, temperature and pH of VPY3 lipases for maximum activity were 30 minutes, 30⁰C and 6 while that for VPY42 were 20 minutes, 20⁰C and 5. Both the lipases were stable at wide range of temperatures, pH and in the presence of metal ions and organic solvents. The enzyme kinetics studies showed that the Km and Vmax values of VPY3 lipase were 0.32mM and 58.24U/mL/min and that for VPY42 lipase were 0.55mM and 178.36U/ml/ min respectively. This indicates that lipases have high substrate affinity and can act as good biocatalysts. These interesting characteristics of purified lipases from mangrove sediment yeasts C.tropicalis and D.mesorugosa in the present study make them highly suitable for biotechnological and industrial applications. [ABSTRACT FROM AUTHOR]

The present research explores, through the density functional theory (DFT) calculations, the viability of graphene-polypyrrole (G/PPy) nanocomposites as an effective material for energy storage in Zn-ion batteries. To this end, the CASTEP calculator in the Materials Studio software was employed to examine the electronic and structural properties of the nanocomposites and their potential to enhance energy storage capabilities of Zn-ion batteries. Specifically, the study investigates the interaction of the Zn-adatom with the nanocomposites, electronic properties, specific capacity, Zn adatom diffusion behavior, structural, and thermal stability, as well as the mechanisms through which the nanocomposites store energy. The results show that the adsorption calculation for PPy onto the graphene nanosheet has an exothermic adsorption energy of -1.68 eV and an adsorption height of 3.28 Å. The loading of Zn atoms onto the Gr/PPy nanocomposite yielded a maximum specific capacity of 510.12 mAh g-1, resulting into a weak adsorption energy of -0.078 eV. The nanocomposite exhibited an extremely low Zn diffusion barrier of 12 meV, enabling a fast Zn diffusion on its surface. These findings suggest that G/PPy nanocomposites hold promise as a material to enhance energy storage in Zn-ion batteries. The study, through DFT calculations, offers valuable insights into the electronic and structural properties of G/PPy nanocomposites and their potentials for improved energy storage in Zn-ion batteries. It thus, contributes significantly to the current understanding of energy storage materials and provides a foundation for further research on the development of more effective and efficient energy storage solutions. [ABSTRACT FROM AUTHOR]

The excessive content of heavy metals and the deficiency of beneficial trace elements in cereals have threatened global food security and human health. As important metal transporters, Natural resistance-associated macrophage proteins (Nramps) are involved in the absorption and transport of various metal ions in plants, including beneficial elements and hazardous heavy metals, yet little is known about their roles in foxtail millet. In this study, 12 Nramps were identified in foxtail millet genome and divided into three clades. Expansion and functional differentiation of SiNramp gene family is evident in the high proportion of gene duplication as well as the diversity in protein structure and expression characteristics. The SiNramp genes exhibited different response patterns to Cd stress in different tissues. Based on the integration of ionome, RNA-seq and orthologous analysis, the association of SiNramp genes with the accumulation of different metal ions was investigated, and the possible functions of several SiNramp genes were predicted, such as SiNramp6 and SiNramp12. In general, this study provides a comprehensive theoretical framework for the study of Nramp genes in foxtail millet and other minor gramineous crops, which will lay a foundation for further research on the mechanism of metal transport and accumulation. [ABSTRACT FROM AUTHOR]

Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing; however, lots of challenges and limitations such as low viscosity, poor salt tolerance, and possible formation damage hinder the application of the conventional simple slickwaterbased fracturing fluid. In addition, nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the slickwater. In this paper, molybdenum disulfide (MoS2) nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing fluid. Firstly, the microstructure characteristics and crystal type of the MoS2 nanosheets were analyzed by SEM, EDS, TEM, XPS, and Raman spectroscopy techniques. Then, a series of evaluation experiments were carried out to compare the performance of MoS2 nanosheet-modified slickwater with the conventional slickwater, including rheology, drag reduction, and sand suspension. Finally, the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically investigated. The results showed that the selfsynthesized MoS2 nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of nanometers. In the nano-composites, each MoS2 nanosheet plays the role of crosslinking point, so as to make the spatial structure of the entire system more compact. Moreover, nanosheet-modified slickwater demonstrates more excellent properties in rheology, drag reduction, and sand suspension. The nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90 °C and 170 s-1. The maximum drag reduction rate achieved 76.3% at 20 °C, and the sand settling time of proppants with different mesh in the nano-composites was prolonged. Spontaneous imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of oil-detaching, and increase the oil recovery to ~35.43%. By observing and analyzing the interfacial behavior of MoS2 nanosheets under stimulated reservoir conditions, it was found that the presence of an interfacial tension gradient and the formation of a climbing film may play an essential role in the spontaneous imbibition mechanism. This work innovatively uses two-dimensional MoS2 nanosheets to modify regular slickwater and confirms the feasibility of flake-like nanomaterials to improve the performance of slickwater. The study also reveals the underlying mechanism of enhanced imbibition efficiency of the nano-composites. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Electrochemistry is the property of Journal of Electrochemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Herein, a convenient on-off fluorescent probe was developed to detect iron ion (Fe 3+ ) with sensitivity and selectivity by using highly luminescent ionic liquid-functionalized carbon quantum dots (CQDs) which was prepared by one-step hydrothermal treatment using citric acid and 1-Aminopropyl-3-methylimidazolium. The sensitivity of CQDs for Fe 3+ was examined by measuring the fluorescence (FL) intensity of various concentrations of Fe 3+ in CQDs solution and the selectivity of CQDs for Fe 3+ was examined by adding different metal ions (Na + , Mg 2+ , Al 3+ , K + , Ca 2+ , Mn 2+ , Zn 2+ , Ag + , Cd 2+ , Pb 2+ and Ba 2+ ) into CQDs solution, respectively. The results indicated that the FL intensity of CQDs showed a good linear response to the concentrations of Fe 3+ in the range of 0–300 μmol L −1 (R 2 = 0.99) with a detection limit of 13.68 μmol L −1 . Furthermore, based on the redox mechanism, after the fluorescent of CQDs was quenched by Fe 3+ , different neurotransmitters and amino acids were added and the FL test show that only ascorbic acid (AA) can recover the intensity of the CQDs/Fe 3+ , indicating that CQDs/Fe 3+ can be further used as a on-off fluorescent probe for the detection of AA. It is expected that our strategy may offer a new approach for developing rapid, low cost and sensitive CQDs-based sensors for environmetal and biological sensing applications. [ABSTRACT FROM AUTHOR]

Porous magnetic hybrids were synthesized and functionalized with glycidol to produce boron-selective adsorbent. The magnetic hybrid (MH) comparatively out-performed the existing expensive adsorbents. MH had a saturation magnetisation of 63.48 emu/g and average pore diameter ranging from meso to macropores. The magnetic hybrids showed excellent selectivity towards boron and resulted in 79–93% boron removal even in the presence of competing metal ions (Na + and Cr 2+ ). Experiments were performed in a column system, and breakthrough time was observed to increase with bed depths and decreased with flow rates. The batch experiments revealed that 60 min was enough to achieve equilibrium, and the level of boron sorption was 108.5 mg/g from a synthetic solution. Several adsorption-desorption cycles were performed using a simple acid–water treatment and evaluated using various kinetic models. The spent adsorbents could be separated easily from the mixture by an external magnetic field. The cost-benefit analysis was performed for the treatment of 72 m 3 /year boron effluent, including five years straight line depreciation charges of equipment. The net profit and standard percentage confirmed that the recovery process is economically feasible. [ABSTRACT FROM AUTHOR]

Microplastics can adsorb and spread a variety of pollutants in the ecosystem posing a threat to human health. One of the common pollution sources of environmental waters is metal ions, which not only adsorb on microplastics but can also promote the adsorption of other invasive species such as environmental DNA. Recently, we showed that environmentally abundant metal ions (Na+, Mg2+ and Ca2+) can promote the adsorption of single-stranded DNA (ssDNA) onto microplastics. Herein, we investigated the effect of transition metal ions including Zn2+ and Mn2+ and compared them with Mg2+ for promoting DNA adsorption. To better mimic environmental DNA, we also used a salmon sperm double-stranded DNA (dsDNA) (~2000 bp). For both ssDNA and dsDNA, the transition metals induced a higher adsorption capacity compared to Mg2+, and that correlated with the higher binding affinity of transition metals to DNA. Although metal-mediated interactions were vital for ssDNA adsorption, the dsDNA adsorbed on the microplastics even in the absence of metal ions, likely due to the abundance of binding sites of the 100-times longer dsDNA. Finally, desorption studies revealed that hydrophobic interactions were responsible for dsDNA adsorption in the absence of metal ions. [ABSTRACT FROM AUTHOR]

Owing to their high redox potential and availability of numerous diffusion channels in metal–organic frameworks, Prussian blue analogs (PBAs) are attractive for metal ion storage applications. Recently, vanadium ferrocyanides (VFCN) have received a great deal of attention for application in sodium-ion batteries, as they demonstrate a stable capacity with high redox potential of ~3.3 V vs. Na/Na+. Nevertheless, there have been no reports on the application of VFCN in lithium-ion batteries (LIBs). In this work, a facile synthesis of VFCN was performed using a simple solvothermal method under ambient air conditions through the redox reaction of VCl3 with K3[Fe(CN)6]. VFCN exhibited a high redox potential of ~3.7 V vs. Li/Li+ and a reversible capacity of ~50 mAh g–1. The differential capacity plots revealed changes in the electrochemical properties of VFCN after 50 cycles, in which the low spin of Fe ions was partially converted to high spin. Ex situ X-ray diffraction measurements confirmed the unchanged VFCN structure during cycling. This demonstrated the high structural stability of VFCN. The low cost of precursors, simplicity of the process, high stability, and reversibility of VFCN suggest that it can be a candidate for large-scale production of cathode materials for LIBs. [ABSTRACT FROM AUTHOR]

Over the past several decades, the international community has been actively engaged in developing a safe method for isolating spent nuclear fuel, high and intermediate level radioactive wase of different degrees of heat generation in deep geological formations on the basis of regulatory requirements existing in each individual country (for example, in the Russian Federation-NP-055-14). Such a storage facility should be equipped with an engineered safety barrier system that combines a range of materials capable of ensuring the safe localization of environmentally and health-threatening nuclear power generation industry and the nuclear industry waste products, in particular. On the basis of the international experience discussed in this article on the design and operation of such facilities, the most universal material in terms of the functions performed as a component of the engineered barrier system is cement and the cement-based product mixed with various components—concrete. Furthermore, due to the possible mutual influence of buffer materials and their transformation over time at interfaces, this work considers the impact of cement-based barriers on other components of engineered barrier systems, the information on which has been accumulated as a result of both analytical laboratory tests and in situ radioactive waste disposal facilities under construction. [ABSTRACT FROM AUTHOR]

A fluorescent sensor ‘ RhAsP ’ prepared from rhodamine hydrazine and 2-hydroxy-acetophenone was designed and synthesised. The characterisation of ‘ RhAsP ’ was also accomplished by using FT-IR, 1 H NMR, 13 C NMR, ESI-MS, elemental analysis, fluorescence and UV/vis spectroscopy. For the purpose of investigating optical sensing behaviour of ‘ RhAsP ’ toward various metal ions including alkali, alkaline earth and transition metal ions (Na + , K + , Ag + , Ca 2+ , Mg 2+ , Cr 3+ , Fe 3+ , Hg 2+ , Cu 2+ , Pb 2+ , Zn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cd 2+ , Al 3+ and Mn 2+ ) in aqueous medium under physiological pH conditions, fluorescence and absorption spectroscopic techniques were carefully conducted. Thereby, ‘ RhAsP ’ showed both colorimetric and fluorometric selective recognition of Hg 2+ from colorless to purple with a reversible ‘ off–on’ fluorescence response. In addition, a nearly 100-fold increase in emission intensity was determined upon the addition of two equivalents Hg 2+ ions. [ABSTRACT FROM AUTHOR]

In this study an experimental work has been done to test the feasibility of using partially dealuminated metakaolin (PDK) with metakaolin (MK) in the production of geopolymer binder. The chemical composition and physical properties of de-aluminated metakaolin was tested. For this purpose, metakaolin (MK) was partially substituted with partially de-aluminated metakaolin (PDK) at ratios of 0-60% by weight. The alkaline activator was NaOH. Geopolymer pastes were cured at room temperature. The compressive strength was measured by testing standard cubes at 7 and 28 days. Satisfactory results have been achieved by using 15, 20, 30, 35 wt.% of PDK. Hence it was suggested to use the local metakaolin with added proportions of PDK up to 35% of metakaolin to produce economic geopolymer binder. It is technically feasible, resulting in a sustainable and environmentally friendly source of vitreous material. The effect of PDK on porosity and compressive strength were tested. The internal microstructure, and hydration were investigated by using modern methods such as, Thermo-gravimetric (TGA) and differential thermal analysis (TGA, DTGA), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The findings assure the potentiality for the application of PDK as a siliceous material can be used in manufacturing of geopolymer cement. [ABSTRACT FROM AUTHOR]

Increasing demand for carbon neutrality has led to the development of new techniques and modes of low carbon production. The utilization of microbiology to convert low-cost renewable resources into more valuable chemicals is particularly important. Here, we investigated the ability of a cellulolytic bacterium, Bacillus subtilis 1AJ3, in switchgrass lignocellulose degradation. After 5 days of culture with the strain under 37°C, cellulose, xylan, and acid-insoluble lignin degradation rates were 16.13, 14.24, and 13.91%, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis and field emission scanning electron microscopy (FE-SEM) indicated that the lignin and surface of switchgrass were degraded after incubation with the bacterial strain. Strain 1AJ3 can grow well below 60°C, which satisfies the optimum temperature (50°C) condition of most cellulases; subsequent results emphasize that acid-heat incubation conditions increase the reducing sugar content in a wide range of cellulosic biomass degraded by B. subtilis 1AJ3. To obtain more reducing sugars, we focused on p-glycoside hydrolase, which plays an important role in last steps of cellulose degradation to oligosaccharides. A p-glycoside hydrolase (Bgl-16A) was characterized by cloning and expression in Escherichia coli BL21 and further determined to belong to glycoside hydrolase (GH) 16 family. The Bgl-16A had an enzymatic activity of 365.29 ± 10.43 U/mg, and the enzyme's mode of action was explained by molecular docking. Moreover, the critical influence on temperature (50°C) of Bgl-16A also explained the high-efficiency degradation of biomass by strain under acid-heat conditions. In terms of potential applications, both the strain and the recombinant enzyme showed that coffee grounds would be a suitable and valuable substrate. This study provides a new understanding of cellulose degradation by B. subtilis 1AJ3 that both the enzyme action mode and optimum temperature limitation by cellulases could impact the degradation. It also gave new sight to unique advantage utilization in the industrial production of green manufacturing. [ABSTRACT FROM AUTHOR]

In recent years, the linear economic model and global warming have shown that it is necessary to move toward a circular economic model. In this scenario, the recycling of waste electrical and electronic equipment (WEEE) with green processes is one of the pending tasks; thus, in the present review, advances in the solid–liquid and liquid–liquid extraction processes, processes among the most important for the recovery of metals from ores or WEEE, with green solvents such as deep eutectic solvents (DES) are presented and analyzed, identifying the present and future challenges. To date, most articles focused on one of the processes, be it solid–liquid or liquid–liquid extraction, while few reports included the entire hydrometallurgical process, which could be due to heterogeneity of the WEEE, a characteristic that influences determining the leaching kinetic and the leaching mechanisms. A deeper understanding of the phenomenon would help improve this process and the next stage of liquid–liquid extraction. This also leads to the fact that, at the liquid–liquid extraction stage, most articles considered synthetic pregnant leach solutions to evaluate each of the variables, whereas the stripping of the ions and the recycling of the DESs in continuous processes is a challenge that should be addressed in future work. From the analysis, for WEEE leaching, it was identified that acid DESs are those achieving the best extraction percentages in the leaching of copper, lithium, and cobalt, among others, where the most studied hydrogen bond acceptor (HBA) is choline chloride with an acid (e.g., citric or lactic acid) as the hydrogen bond donor (HBD). For the liquid–liquid extraction of ions is a greater variety of HBAs (e.g., lidocaine, trioctylphosphine oxide and triphenyl phosphate) and HBDs (e.g., decanoic acid, thenoyltrifluoroacetone, and benzoyltrifluoroacetone) used; however, studies on the extraction of cobalt, lithium, copper, and nickel stand out, where the pH and temperature parameters have great influence. [ABSTRACT FROM AUTHOR]

The aim of these studies was to perform thorough research on the influence of alkali metal ions (Li, Na, K and Cs) on the properties of nanogold catalysts supported on ceria–zirconia. The addition of alkali metal ions onto CeO2 further affected the reducibility, which was not noted for the Zr-doped support (Ce0.85Zr0.15O2). Despite the substantial impact of alkali metal ions on the reducibility of ceria, the activity in CO oxidation did not change much. In contrast, they do not have a large effect on the reducibility of Au/CZ but suppressed the activity of this system in CO oxidation. The results show that for CO oxidation, the negative effect of potassium ions is greater than that of sodium, which corresponds to the shift in the Tmax of the reduction peak towards higher temperatures. The negative effect of Li+ and Cs+ spans 50% CO conversion. The negative effect was visible for CO oxidation in both the model stream and the complex stream, which also contained hydrocarbons and NO. In the case of NO oxidation to NO2, two temperature regimes were observed for Au + 0.3 at% K/CZ, namely in the temperature range below 350 °C; the effect of potassium ions was beneficial for NO oxidation, whereas at higher temperatures, the undoped gold catalyst produced more NO2. [ABSTRACT FROM AUTHOR]

The interaction of the metal ions Na, Mg2, Ca2, and Zn2숫 cytosine havebeen reinvestigated at the density functional, Møller–Plesset,and coupled cluster levels of theory, including hitherto unstudiedtautomeric forms. It has been found that the interaction of the metalion has a varying and often significant effect on the stabilitiesof the various tautomers, in some cases making most stable rare tautomericforms. The results have been analyzed with respect to method and roleof ion in binding, and confirm that, as has been found for the basecytosine tautomers, B3LYP does not give energetics consistent withhighly accurate post-SCF methods for their interaction with thesemetal ions. [ABSTRACT FROM AUTHOR]

In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na and K) and divalent metal ions (Ca, Mg, and Zn) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of aqueous oxytocin solutions was determined by RP-HPLC and HP-SEC after 4 weeks of storage at either 4°C or 55°C. Addition of sodium or potassium ions to acetate- or citrate-buffered solutions did not increase stability, nor did the addition of divalent metal ions to acetate buffer. However, the stability of aqueous oxytocin in aqueous formulations was improved in the presence of 5 and 10 mM citrate buffer in combination with at least 2 mM CaCl, MgCl, or ZnCl and depended on the divalent metal ion concentration. Isothermal titration calorimetric measurements were predictive for the stabilization effects observed during the stability study. Formulations in citrate buffer that had an improved stability displayed a strong interaction between oxytocin and Ca, Mg, or Zn, while formulations in acetate buffer did not. In conclusion, our study shows that divalent metal ions in combination with citrate buffer strongly improved the stability of oxytocin in aqueous solutions. [ABSTRACT FROM AUTHOR]

Based on donor (D)−acceptor (A) biphenyl (b) type molecules, a family of fluorescent reporters with integrated acceptor receptors and noncoordinating and coordinating donor substituents of varying strength has been designed for ratiometric emission sensing and multimodal signaling of metal ions and protons. In part 2 of this series on such charge transfer (CT) operated mono- and bifunctional fluorescent devices, the cation coordination behavior of the sensor molecules bpb-R equipped with a proton- and cation-responsive 2,2‘:6‘,2‘ ‘-terpyridine (bp) acceptor and either amino-type donor receptors (R DMA, A15C5 monoaza-15-crown-5) or nonbinding substituents (R CF3, H, OMe) is investigated employing the representative metal ions Na(I), Ca(II), Zn(II), Hg(II), and Cu(II) and steady-state and time-resolved fluorometry. The bpb-R molecules, the spectroscopic behavior and protonation behavior of which have been detailed in part 1 of this series, present rare examples for CT-operated bifunctional fluorescent probes that can undergo consecutive and/or simultaneous analyte recognition. The analyte-mediated change of the probes'' intramolecular CT processes yields complexation site- and analyte-specific outputs, i.e., absorption and fluorescence modulations in energy, intensity, and lifetime. As revealed by the photophysical studies of the cation complexes of these fluoroionophores and the comparison to other neutral and charged D−A biphenyls, the spectroscopic properties of the acceptor chelates of bpb-R and A- and D-coordinated bpb-R are governed by CT control of an excited-state barrier toward formation of a forbidden charge transfer state, by the switching between analytically favorable anti-energy and common energy gap law type behavior, and by the electronic nature of the ligated metal ion. This accounts for the astonishingly high fluorescence quantum yields of the acceptor chelates of bpb-R equipped with weak or medium-sized donors and the red emission of D- and A-coordinated bpb-R observed for nonquenching metal ions. [ABSTRACT FROM AUTHOR]

Bi2S3 was dissolved in the presence of NaCl in the ionic liquid [BMIm]Cl ⋅ 4AlCl3 (BMIm=1‐n‐butyl‐3‐methylimidazolium) through annealing the mixture at 180 °C. Upon cooling to room temperature, orange, air‐sensitive crystals of Na(Bi7S8)[S(AlCl3)3]2[AlCl4]2 (1) precipitated. X‐ray diffraction on single‐crystals of 1 revealed a triclinic crystal structure that contains (Bi7S8)5+spiro‐dicubanes, [S(AlCl3)3]2− tetrahedra triples, isolated [AlCl4]− tetrahedra, and sodium cations. [ABSTRACT FROM AUTHOR]

The effect of alkali metal ions (Na+ or K+) on the acid–base and catalytic properties of Zn-Mg(Zr)Si oxide systems in the process of obtaining 1,3-butadiene from ethanol was studied. It was found that the modification of Zn-MgSi oxide systems promotes an increase in the 1,3-butadiene selectivity (at temperatures ≥670 K) by reducing the number of formation sites of by-products. In the composition of Zn-ZrSi oxide systems, alkali metal cation additives lead to a decrease in the ethene and diethyl ether selectivity due to a decrease in the content of strong acid sites that are active in the ethanol dehydration reaction. [ABSTRACT FROM AUTHOR]

A novel lipase, SCNL, was isolated from Staphylococcus caprae NCU S6 strain in the study. The lipase was purified to homogeneity with a yield of 6.13% and specific activity of 502.76 U/mg, and its molecular weight was determined to be approximately 87 kDa. SCNL maintained above 80% of its initial activity at a wide range of temperatures (20–50 °C) and pH values (6–11), with an optimal temperature at 40 °C and optimal pH at 9.0 with p-nitrophenyl palmitate as a substrate. SCNL exhibited a higher residual activity than the other staphylococcal lipases in the presence of common enzyme inhibitors and commercial detergents. The lipase activity was enhanced by organic solvents (isooctane, glycerol, DMSO and methanol) and metal ions (Na+, Ba2+, Ca2+, and Mn2+). The Km and Vmax values of SCNL were 0.695 mM and 262.66 s−1 mM−1, respectively. The enzyme showed a preference for p-NP stearate, tributyrin and canola oil. These biochemical features of SCNL suggested that it may be an excellent novel lipase candidate for industrial and biotechnological applications. [ABSTRACT FROM AUTHOR]

Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung colonizer, producing an extracellular matrix (ECM) composed predominantly of the extracellular polysaccharide (EPS) alginate. The ECM limits antimicrobial penetration and, consequently, CF sufferers are prone to chronic mucoid P. aeruginosa lung infections. Interactions between cations with elevated concentrations in the CF lung and the anionic EPS, enhance the structural rigidity of the biofilm and exacerbates virulence. In this work, two large mucoid P. aeruginosa EPS models, based on β-D-mannuronate (M) and β-D-mannuronate-α-L-guluronate systems (M-G), and encompassing thermodynamically stable acetylation configurations–a structural motif unique to mucoid P. aeruginosa–were created. Using highly accurate first principles calculations, stable coordination environments adopted by the cations have been identified and thermodynamic stability quantified. These models show the weak cross-linking capability of Na+ and Mg2+ ions relative to Ca2+ ions and indicate a preference for cation binding within M-G blocks due to the smaller torsional rearrangements needed to reveal stable binding sites. The geometry of the chelation site influences the stability of the resulting complexes more than electrostatic interactions, and the results show nuanced chemical insight into previous experimental observations. [ABSTRACT FROM AUTHOR]

Context: We investigated the interaction between glycine and Li + in water environment based on the Gly·Li + (H 2 O) n (n = 0-8) cluster. Our study shows that for Gly·Li + , Li + binds to both carbonyl oxygen and amino nitrogen to form a bidentate structure, and the first three water molecules preferentially interact with Li + . For n = 0-5, the complexes of Gly·Li + (H 2 O) n exist in neutral form, and when the water number reached 6, the complex can coexist in neutral and zwitterionic form, then zwitterionic structures are dominant for n = 7, 8. The analyses by RDG, AIM, and ESP in conjunction with the calculated interaction energies show that the interaction between Li + and Gly decreases gradually with the water molecules involved successively from n = 1 to 6 and then increases for n = 7-8. Additionally, the infrared spectra of Gly·Li + (H 2 O) n (n = 0-8) are also calculated., Methods: The initial structures were optimized using Gaussian 09 program package in B3LYP-D3 (BJ)/6-311G(d, p) method, and the frequency was calculated with 6-311 + G(2d, p) basis set. GaussView5.0.9 was used to view simulation infrared spectra. The noncovalent interaction method (NCl), energy decomposition (EDA), atoms in molecules (AIM) analysis, and electrostatic potential (ESP) analyses were conducted using Multiwfn software to gain a deeper understanding of the interaction properties of Gly, Li + , and water., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A detailed study of structural, magnetic, magnetocaloric and magneto-transport properties of Nd0.6Sr0.4−xKxMnO3 (x = 0.0, 0.1 and 0.2) manganite, prepared using the sol–gel process, has been performed. All compounds are pure single phase crystallized in the orthorhombic system with Pnma space group. Rietveld analysis reveals the dependence of structural properties upon the monovalent substitution rate. The nanometric size determined through Debye–Scherrer formula is validated by SEM micrographs. Magnetization curves as a function of temperature exhibit a clear ferromagnetic to paramagnetic (FM-PM) phase transition at Curie temperature (Tc) which is found to decrease with increasing K fraction x. Large relative cooling power (RCP) value standing for about 50% of that noticed in pure Gd under magnetic field of 5 T is achieved for x = 0.0 compound, indicating its potential application in the cooling fields. Electrical resistivity curves as a function of temperature exhibit a metal–semiconductor (M-Sc) transition for all samples. The magnetoresistance (MR) ratio reaches its highest value for x = 0.2 sample under an external magnetic field of 2 T making this material a promising magnetoresistive sensor used in a wide range of industrial applications. Significant values of thermal coefficient of resistivity (TCR) are noted under zero external magnetic field giving these materials a potential application for the infrared (IR) and bolometric detectors. [ABSTRACT FROM AUTHOR]

The catalytic effects of alkali metal ions (Na+ and K+) on NOx precursor formation during coal pyrolysis were investigated using the N-containing compound pyridine as a model compound. Density functional theory calculations at the B3LYP/6-31G (d, p) level of theory were conducted to elucidate the mechanism of pyridine pyrolysis and the pathways for HCN formation. The calculation results indicate that Na+ and K+ have distinct influences on different pyrolysis reactions; these alkali metal ions facilitate the initial hydrogen transfer from C1 to N and C2, whereas they hinder the other hydrogen migration reactions. Both Na+ and K+ significantly reduce the activation energies for C–C bond breakage and triple-bond formation, whereas they increase the activation energies for the isomerization reactions. The different effects essentially result from the distinct charge distributions induced by the two ions. Due to the distinct influences on the different reactions, the rate-determining steps are modulated, affecting the competitiveness of the different possible pathways of HCN formation. The formation of HCN from pyridine is promoted in the presence of Na+ and K+ because all the overall activation energies are decreased for different pathways. The calculation results agree well with previous experimental studies. Thus, the findings offer a new and promising approach to reveal the formation mechanism of NOx and facilitate the control of NOx for coal utilization. [ABSTRACT FROM AUTHOR]

Ni- and Co-incorporated CH3NH3PbI3 perovskite solar cells were fabricated and characterized to optimize the photovoltaic and optical properties related to surface morphology, crystal growth and orientation, and electronic structures. Partially replacing Pb with Ni or Co in the perovskite crystals improved the photovoltaic performance and carrier mobility based on the effective mass in the band structure. In particular, the addition of both Ni and Rb compounds to perovskite improved the long-term stability of the photovoltaic cells, which depended on surface modification and coverage, crystal growth, and the high (100) orientation in the perovskite layer. The short-circuit current density of the cells was increased by promoting the generation and mobility of photoinduced carriers, which were inversely proportional to the effective mass ratio. Electron correlation was associated with the promotion of charge transfer owing to the hybridization between the 3d orbitals of Ni and the 5p orbitals of the I atoms near the valence band state. [ABSTRACT FROM AUTHOR]

The method of preparation and its processing parameters have a strong effect on the structure and non-linear properties of the materials. A sol–gel technique is highly favoured owing to its lower production temperature, nanoparticle size, inter-diffusion of cations and cost-effectiveness. Sodium potassium niobate (KNN) is the most capable environmentally friendly material, which has been studied for the last decades as a promising candidate among all lead-free perovskites materials. In this article, we have prepared KNN ceramics by using the wet chemical sol–gel route. To control the volatility of (Na, K) ions at higher production temperature, we have added 10–20% (Na, K) alkali metal in the precursor solution. The phase investigation and crystalline character of the ceramics have been analysed by X-ray diffractometer. Raman spectroscopy analysis disclosed that pure KNN ceramic has a better crystalline and perovskite structure. FTIR analysis is done to analyse the presence of the functional group in the wavenumber range of 4000–500 cm−1. The surface microstructure analysis and morphology of the KNN ceramics have been studied by using field emission scanning electron microscopy techniques. Further, the optical and photoluminescence behaviour has been studied at room temperature to know its practical applications in various electro-optic device applications. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticle embedded on guar gum (AgNP/GG) nanocomposite was synthesized thoroughly in greenway via a simple in situ method by silver salt reduction using the guar gum (GG) polymer matrix. The highly water-soluble polysaccharide material (GG) was served as both stabilizing and reducing agent. Its structure and morphology were characterized by XRD, FT-IR, TEM, and UV−Vis spectroscopy. EIS, CV, and DPV methods have also been employed to investigate the electrochemical performance of the AgNP/GG nanocomposite. Analytical parameters such as loading amount of catalyst, scan rate, pH value, cyclic stability, repeatability, and reproducibility were optimized. The AgNP/GG/SPCE shows a distinct electrocatalytic oxidation of diphenylamine (DPA) in a wide linear range (WLR) of 0.01−9.09 µM, a higher sensitivity of 6.879 µM cm−2, and a limit of detection (LoD) of 5.4 nM (S/N = 3). The fabricated electrode exhibits an outstanding electrocatalytic performance in terms of good reproducibility, high stability, and acceptable anti-interference ability. In addition, this work advances the feasibility to determine DPA in apple juice sample with satisfactory recovery results. [ABSTRACT FROM AUTHOR]

Context. The Rosetta spacecraft escorted Comet 67P/Churyumov-Gerasimenko for 2 yr along its journey through the Solar System between 3.8 and 1.24 au. Thanks to the high resolution mass spectrometer on board Rosetta, the detailed ion composition within a coma has been accurately assessed in situ for the very first time. Aims. Previous cometary missions, such as Giotto, did not have the instrumental capabilities to identify the exact nature of the plasma in a coma because the mass resolution of the spectrometers onboard was too low to separate ion species with similar masses. In contrast, the Double Focusing Mass Spectrometer (DFMS), part of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis on board Rosetta (ROSINA), with its high mass resolution mode, outperformed all of them, revealing the diversity of cometary ions. Methods. We calibrated and analysed the set of spectra acquired by DFMS in ion mode from October 2014 to April 2016. In particular, we focused on the range from 13–39 u q−1. The high mass resolution of DFMS allows for accurate identifications of ions with quasi-similar masses, separating 13C+ from CH+, for instance. Results. We confirm the presence in situ of predicted cations at comets, such as CH m+ $_m^+$ m + (m = 1−4), HnO+ (n = 1−3), O+, Na+, and several ionised and protonated molecules. Prior to Rosetta, only a fraction of them had been confirmed from Earth-based observations. In addition, we report for the first time the unambiguous presence of a molecular dication in the gas envelope of a Solar System body, namely CO 2++ $_2^{++}$ 2 + + . [ABSTRACT FROM AUTHOR]

In this work the potential of comparative transcriptomics was explored of Saccharomyces (S.) cerevisiae and S. pastorianus for their discrimination. This way an alternative should be demonstrated to comparative genomics, which can be difficult as a result of their aneuoploid genomes composed of mosaics of the parental genomes. Strains were selected according to their application in beer brewing, i.e. top and bottom fermenting yeasts. Comparative transcriptomics was performed for four strains each of commercially available S. cerevisiae (top fermenting) and Saccharomyces pastorianus (bottom fermenting) brewing yeasts grown at two different temperatures to mid-exponential growth phase. A non-reference based approach was chosen in the form of alignment against a de novo assembled brewery-associated pan transcriptome to exclude bias introduced by manual selection of reference genomes. The result is an analysis workflow for self-contained comparative transcriptomics of Saccharomyces yeasts including, but not limited to, the analysis of core and accessory gene expression, functional analysis and metabolic classification. The functionality of this workflow is demonstrated along the principal differentiation of accessory transcriptomes of S. cerevisiae versus S. pastorianus strains. Hence, this work provides a concept enabling studies under different brewing conditions. [ABSTRACT FROM AUTHOR]

Furocoumarin (furo[3,2-c]coumarin) derivatives have been synthesized from single step, high yielding (82–92%) chemistry involving a 4-hydroxycoumarin 4 + 1 cycloaddition reaction. They are characterized by FTIR, 1H-NMR, and, for the first time, a comprehensive UV-Vis and fluorescence spectroscopy study has been carried out to determine if these compounds can serve as useful sensors. Based on the fluorescence data, the most promising furocoumarin derivative (2-(cyclohexylamino)-3-phenyl-4H-furo[3,2-c]chromen-4-one, FH), exhibits strong fluorescence (ФF = 0.48) with long fluorescence lifetime (5.6 ns) and large Stokes' shift, suggesting FH could be used as a novel fluorescent chemosensor. FH exhibits a highly selective, sensitive and instant turn-off fluorescence response to Fe3+ over other metal ions which was attributed to a charge transfer mechanism. Selectivity was demonstrated against 13 other competing metal ions (Na+, K+, Mg2+, Ca2+, Mn2+, Fe2+, Al3+, Ni2+, Cu2+, Zn2+, Co2+, Pb2+ and Ru3+) and aqueous compatibility was demonstrated in 10% MeOH-H2O solution. The FH sensor coordinates Fe3+ in a 1:2 stoichiometry with a binding constant, Ka = 5.25 × 103 M−1. This novel sensor has a limit of detection of 1.93 µM, below that of the US environmental protection agency guidelines (5.37 µM), with a linear dynamic range of ~28 (~2–30 µM) and an R2 value of 0.9975. As an exemplar application we demonstrate the potential of this sensor for the rapid measurement of Fe3+ in mineral and tap water samples demonstrating the real-world application of FH as a "turn off" fluorescence sensor. [ABSTRACT FROM AUTHOR]

High-temperature lithium battery system operated between 150 and 300 °C is highly desirable to be applied in oil/gas and geothermal explorations. However, the development of cathode material for high-temperature lithium batteries is relatively sluggish. In this study, LiNi1/3Co1/3Mn1/3O2 (NCM) is coated with Li2MoO4 by a facile solid-state reaction between MoO3 and surface lithium residue and the resulting composite is applied in high-temperature lithium batteries as a novel cathode material. Such a strategy can not only remove lithium residue components, but also facilitate lithium-ion transport in NCM through the resulting Li2MoO4 coating layer. At 200 °C, the discharge capacity and rate capacity of Li2MoO4 coated NCM are dramatically improved compared to the pristine one. At 300 °C, the electrochemical performance of 4m-NCM is better than other samples, and each sample exhibits better electrochemical performances than it is at 200 °C due to the enhanced kinetics in high temperature. [ABSTRACT FROM AUTHOR]

The present study demonstrates the production and thrombolytic potential of a novel thermostable thiol-dependent fibrinolytic protease by Bacillus cereus RSA1. Statistical optimization of different parameters was accomplished with Plackett-Burman design and validated further by central composite design with 30.75 U/mL protease production. Precipitation and chromatographic approaches resulted in 33.11% recovery with 2.32-fold purification. The molecular weight of fibrinolytic protease was 40 KDa and it exhibited a broad temperature and pH stability range of 20-80 ffiC and pH 5-10 with utmost activity at 50 ffiC and pH 8, respectively. The protease retained its fibrinolytic activity in organic solvents and enhanced the activity in solutions with divalent cations (Mn2+, Zn2+, and Cu2+). The enzyme kinetics revealed Km and Vmax values of 1.093 mg/mL and 52.39 µg/mL/min, respectively, indicating higher affinity of fibrinolytic activity towards fibrin. Also, complete inhibition of fibrinolytic activity with DFP and a 2-fold increase with DTT and β-mercaptoethanol indicates its thiol-dependent serine protease nature. MALDI-TOF analysis showed 56% amino acid sequence homology with Subtilisin NAT OS = Bacillus subtilis subsp. natto. The fibrinolysis activity was compared with a commercial thrombolytic agent for its therapeutic applicability, and fibrinolytic protease was found highly significant with absolute blood clot dissolution within 4 h in in vitro conditions. The isolated fibrinolytic protease of Bacillus cereus RSA1 is novel and different from other known fibrinolytic proteases with high stability and efficacy, which might have wide medicinal and industrial application as a thrombolytic agent and in blood stain removal, respectively. [ABSTRACT FROM AUTHOR]

In this paper, polycrystalline lead-free K0.5Na0.5NbO3 (KNN) ceramics were manufactured by a sol–gel reaction route. The effect of calcination temperature on optical, photoluminescence and electrical parameters has been studied. The optical parameters were investigated by using reflectance spectroscopy of ceramics which revealed a red shift in the wavelength with a rise in calcination temperature. The photoluminescence spectrum has an emission band in the UV–visible region at room temperature. Phase determination of KNN ceramics was analyzed by using an x-ray diffractometer. The microstructure and surface morphology of the KNN ceramic were studied by field emission scanning electron microscopy. I–V characteristics have been studied which revealed an ohmic conduction mechanism at higher applied electric voltages. The dependence of dielectric constant, AC conductivity and impedance plots on frequency have been studied at room temperature. The cole–cole plots have a linear curve, which disclosed that KNN ceramics have good insulating properties at room temperature. [ABSTRACT FROM AUTHOR]

Aqueous magnesium ion batteries have been identified as potential electrochemical energy storage system due to their similar electrochemical properties to lithium, safety, high abundance, and low cost. Here, micron-sized Na0.7MnO2.05 is prepared by a facile sol-gel method used for cathode material in aqueous magnesium ion batteries. XRD, XPS, SEM, TEM, and EDS were used to test the composition, structure, and morphology of Na0.7MnO2.05. Na0.7MnO2.05 material is electro-chemical active although the intercalation/deintercalation is much difficult for Mg2+. The reversible specific capacities of the Na0.7MnO2.05 cathode material are estimated to be ca. 40, 35, 22, and 13 mAh·g−1 at the current density of 1 C, 2 C, 5 C, and 10 C, respectively. When the current density comes back to 1 C, the charge capacities recover to 40 mAh·g−1. Furthermore, EIS and GITT measured show that the diffusion coefficient of Mg2+ ion in lattice of Na0.7MnO2.05 varies from 2.17 × 10−11 cm2·s−1 to 7.81 × 10−11 cm2·s−1 in charge process and changes from 6.34 × 10−12 cm2·s−1 to 7.14 × 10−11 cm2·s−1 in discharge process. [ABSTRACT FROM AUTHOR]