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To investigate the quantitative relationship between ionic potential and coal ash fusibility, the chemical compositions and ash fusion temperatures (AFTs) of 214 coal ashes were tested. The prediction models of AFTs with the metal ionic potential concentration ( C M P = ∑ w i ∗ z i M i ∗ r i ∑ w i / M i ) were established by linear fitting. The mineral evolution under different CMP was calculated by FactSage 7.2. and was used to reveal the effect mechanism of CMP on AFTs. The results showed that AFTs initially emerged a negative correlation (24.13 nm−1

Chemical durability of lanthanide zirconates (A2Zr2O7) (A = La-Yb) under near-field environments is important for evaluating their application as potential nuclear waste forms. In this work, A2Zr2O7 (A = La-Yb) are synthesized by spark plasma sintering with controlled microstructure and their chemical durability are evaluated in a nitric acid solution (pH = 1). Scanning transmission electron microscopy analysis reveals an amorphous passivation film either enriched with Zr or lanthanide. The complex chemistry of the passivation films can be correlated with a transition in corrosion mechanisms from a preferential release of lanthanide in La2Zr2O7 to a preferential release of Zr in Er2Zr2O7 and Yb2Zr2O7. These results suggest a dominant mechanism of incongruent dissolution and surface reorganization for the formation of passivation films. Strong correlations are identified between the leaching rates and cation ionic size, ionic potential, electronegativity differences between A-site cation and Zr, and bonding valence sum of oxygen, suggesting important impacts of structural and bonding characteristics in controlling chemical durability of lanthanide zirconates.

Two diglycolamide (DGA) functionalized poly(propylene imine)diaminobutane dendrimers, first generation (Gen I) and second generation (Gen II), termed as LI and LII, were used for the extraction of the tetravalent actinide ions Np4+ and Pu4+ from nitric acid medium. The metal ion extraction followed a ‘solvation’ type mechanism showing increasing metal ion extraction with increasing nitric acid concentration with species of the type: M(NO3)4·L (M = Np or Pu) with some contribution of M(NO3)4·2L for Pu. Pu4+ formed much stronger complexes with both DGA-dendrimer ligands as compared with Np4+, as reflected in their two-phase extraction constants and higher ΔH values, attributed to its higher ionic potential. Binding of the metal ions was to one ‘DGA pocket’ in each of the dendrimers. The structure and bonding analysis was done on the basis of DFT studies.

Long-term studies of the North Caucasian geochemical province allowed to establish regional abundances and calculate accumulation (dispersion) factors for chemical elements in rocks, soils, and plants. Certain natural regional patterns characterize the province. Associations of elements in high and low concentrations are often determined by the predominant composition of rocks: carbonate-terrigenous, terrigenous, and igneous. The study of the average contents of several chemical elements in the soils of the province showed that the association of accumulated elements includes metals with different migration characteristics. Thus, despite the rather close values of the ionic radii, Pb, Zn, Cu, and Li (judging by the ionic potential) are characterized by the formation of cations, while Mn, Mo, and Zr form complex ions. Such elements as Zn, Cu, and Pb are mainly accumulated on hydrosulfuric barriers, while Mo, Co, and Mn are stopped by oxygenous barriers. For Cu, Zn, Mo, and Co, biogenic accumulation plays a significant role, while for Pb and Ni it is practically absent. The absolute dispersion of the elements did not reach environmentally hazardous values, although it indicates a fairly intensive migration. In woody plants, Ba, Nb, Sc, Sr, and Zn are accumulated most intensively.

The information on the compatibility of lead–boron–silicate glass of various compositions and ruthenium(IV) oxide compounds is systematized. The chemical processes occurring between them are established in terms of the theory of the acid-base interaction. The informative indicators that determine the direction of such interaction are the acidity, ionic potential, or orbital electronegativity of the components included in the composite materials. The established regularities can be used for selecting the composition of lead- and cadmium-free glass in the development of advanced ruthenium resistors and ruthenium-containing materials.

The impact of the chemical structure on ion transport, nanoscale morphology, and dynamics in polymerized imidazolium-based ionic liquids is investigated by broadband dielectric spectroscopy and X-ray scattering, complemented with atomistic molecular dynamics simulations. Anion volume is found to correlate strongly with Tg-independent ionic conductivities spanning more than 3 orders of magnitude. In addition, a systematic increase in alkyl side chain length results in about one decade decrease in Tg-independent ionic conductivity correlating with an increase in the characteristic backbone-to-backbone distances found from scattering and simulations. The quantitative comparison between ion sizes, morphology, and ionic conductivity underscores the need for polymerized ionic liquids with small counterions and short alkyl side chain length in order to obtain polymer electrolytes with higher ionic conductivity.

Glass fertilizers in the phosphate systems were melted at 900-950 °C with a soaking period of 1 h. Leaching study of these glasses with a maximum time period of 300 h was conducted under Soxhlet distillation condition with distilled water. Weight loss and the leach rates of the glass fertilizer samples were calculated from BET surface area measurements. They were in the range of 6.3x10-3 to 2.3x10-3 g.m-2.h-1 at 90 °C. The effect of different modifier ions like Na+, Fe3+, Mg2+, Ca2+, and K+ in the basic phosphate networks on melting and time of melting has been found to be evident. The pH determination ranging from 4.80 up to 7.50 of the leachate solution at ambient temperature under varying time intervals showed interesting and regular variations. The leaching study of such glasses under Soxhlet condition showed Ca2+, Mg2+, and K+ to be good candidates as modifier towards faster leaching. The findings have been corroborated in terms of ionic size, ionic radius, and hence the ionic potential of the modifier ions incorporated into the glass structure. The application of glass fertilizers was made on kharif paddy. Resumo Fertilizantes de vidro nos sistemas de fosfato foram fundidos a 900-950 °C por 1 h. Foi realizado estudo de lixiviação desses vidros com um período máximo de 300 h, em condição de destilação Soxhlet com água destilada. A perda de massa e as taxas de lixiviação das amostras de fertilizantes de vidro foram calculadas a partir de medições da área superficial de BET, que foram na faixa de 6,3.10-3 a 2,3.10-3 g.m-2.h-1 a 90 °C. O efeito de diferentes íons modificadores, como Na+, Fe3+, Mg2+, Ca2+ e K+, nas redes de fosfato na fusão e no tempo de fusão foi evidente. A determinação do pH variando de 4,80 a 7,50 da solução de lixiviado à temperatura ambiente, em diferentes intervalos de tempo, mostrou variações interessantes e regulares. O estudo de lixiviação desses vidros na condição de Soxhlet mostrou que Ca2+, Mg2+ e K+ são bons candidatos como modificadores para uma lixiviação mais rápida. Os resultados foram corroborados em termos de tamanho iônico, raio iônico e, portanto, potencial iônico dos íons modificadores incorporados na estrutura do vidro. A aplicação de fertilizantes vítreos foi realizada na planta de arroz.

PEDOT PSS has been studied as a silicon-based binder due to its inherent superior electricity and electrochemical stability. However, it cannot effectively alleviate the huge volume changes of silicon during lithiation/delithiation due to its linear structure, resulting in poor cycling stability. Ion-cross-linking is a usual method to cross-link linear polymers into 3D structures. In this paper, multivalent cations of the 5th period and Group 2 cross-linked PEDOT:PSS were applied as silicon anode binders and studied systematically. It was found that the variation trend of viscosity and conductivity of PEDOT:PSS after cross-linking was consistent with that of ionic potential and softness parameters of multivalent cations. The mesostructure of a binder after cross-linking is influenced by the solubility product constant of sulfites or hydroxides of cations and the growth characteristics of crystals. An Sn4+-cross-linked binder displayed increased viscosity and electrical conductivity and higher reduced modulus and hardness due to its positive softness parameter and higher ion potential. The Si electrode with the Sn4+-cross-linked binder showed improved cycling stability (1876.4 mAh g-1 compared with 1068.4 mAh g-1 of the electrode with the pure PEDOT:PSS binder after 100 cycles) and superior rate capability (∼800 mAh g-1 at an ultrahigh current density of 8.0 A g-1).

The effects of various alkali metal promoters on the structure–performance relationship of cobalt–manganese (CoMn) catalysts for the Fischer–Tropsch synthesis (FTS) reaction have been investigated. The electronic promotion effects are correlated with the ionic potential (IP) of the alkali metals, which represents their electronic polarizability. The presence of alkali metal promoters in the CoMn catalysts is beneficial for the formation and stabilization of the Co2C phase. With an increase in the IP of the alkali metal promoters, the active phase was found to transition from Co2C nanospheres to Co2C nanoprisms and then to a mixture of fcc Co0 and Co2C nanospheres. In addition, the catalytic performance also changed with the transition in the active phase. For the Co2C nanospheres, high CH4 selectivity and low activity were observed. A promising catalytic performance for Fischer–Tropsch to olefins (FTO) with low CH4 selectivity and high C2–4= selectivity was achieved for the Co2C nanoprisms. However, low C2–4= selectivity with high activity was found for a mixture of fcc Co0 and Co2C nanospheres. It is suggested that the alkali metal promoters in the CoMn catalysts have two different promotion effects that are enhanced with IP: (1) the electronic effect to enhance the CO dissociation probability and benefit the formation of Co2C and (2) the facet stabilization effect to stabilize the Co2C nanoprisms with specific exposed (101) and (020) facets under the FTO reaction conditions.

Ultrafast tunnel ionization enables femtosecond time-resolved dynamic measurements of the retro-Diels–Alder reactions of positively charged cyclohexene, norbornene, and dicyclopentadiene. Unlike the reaction times of 500–600 ps that are observed following UV excitation of neutral species, on the ionic potential energy surfaces, these reactions occur on a single picosecond timescale and, in some cases, exhibit vibrational coherence. In the case of norbornene, a 270 cm−1 vibrational mode is found to modulate the retro-Diels–Alder reaction.

The recent discoveries of Ca-fluoride melt in magmatic systems, especially in peralkaline granites with rare earth element enrichment, has raised questions about the presence and nature of liquid immiscibility in CaF2-granite systems, as well as the partitioning behavior of trace elements between such immiscible liquids. We have experimentally explored the immiscibility in this system using natural granite-fluorite starting materials at fast-and slow-cooling rates, temperatures from 500 °C to 1200 °C and 1 atmosphere pressure. Our experiments confirm the presence of a miscibility gap in the CaF2-granite system over a wide range of temperatures. The two immiscible liquids are a mafic fluorosilicate melt (fm) with high CaO and F and a felsic oxysilicate melt (sm) with high SiO2 and alkalis. Immiscibility is encountered when the bulk F-content exceeds approximately 4.4 wt% at 1200 °C and then rapidly decreases to only 0.75 wt% at low temperature (below 900 °C). This indicates that calcic magmas are able to evolve to the liquid immiscibility domain by the residual enrichment of fluorine resulting from fractional crystallization, and that liquid immiscibility should be common. The peritectic reaction fm = sm + fluorite removes the fluorosilicate liquid around 600 °C and could explain the absence of fluorosilicate observations in natural granites. The compositions of the liquids in fast-cooling experiments show a significantly larger miscibility gap which is characterized by, compared to slow-cooling runs, similar sm compositions but higher Ca and F content in fm. This difference is caused by suppression of fluorite nucleation and is interpreted as a metastable extension of the high temperature liquid immiscibility. Immiscibility results in strong fractionation of trace elements which is primarily governed by melt structure and the ionic potential (Z/r) of the elements. The behavior of trace elements can be categorized into three groups: 1. Network formers (Si, Al, Ga, Pb, B) partition into the oxysilicate melt; 2. The partitioning of the alkalis and alkali earths is strongly dependent on the ionic potential, with the partitioning coefficients (D fm/sm) in the order DCs

A large quantity of livestock manure and sewage sludges produced annually in China, and the co-gasification with coal provides a promising way for these clean and large-scale utilization. The livestock manure and sewage sludges generally contain high phosphorus content. To explore the influences of phosphorus on the fusion temperatures (AFTs) of different coals and their mechanisms, the ash fusion variation behaviours of high aluminum Shajuzi coal (SJZ) and high calcium Zhundong coal (ZD) or Yimi coal (YM)) with different mass ratio phosphorus pentoxides (P2O5) were investigated by an AFT tester, x-ray diffraction, and FactSage software. The P2O5 addition could change the AFTs of three coals effectively, however the changing trend was different due to the difference in their ash-composition. With increasing P2O5 mass ratio, low melting point (MP) berlinite formation and high MP mullite content decrease resulted in decreases in the AFTs of SJZ mixture; while high MP calcium phosphates formation led to the AFTs of ZD or YM mixture increase. At high temperature the silicon in silicate or silicaluminate in ash compositions was gradually substituted by phosphorus with increasing P2O5 mass ratio and transformed into different MP phosphates because the ionic potential of P5+ (147 nm−1) was higher than that of Si4+ (95 nm−1), which resulted in different variation behaviours in the AFTs of mixture.

Zeolites Na,Cs-RHO, Cd,Cs-RHO, and Li,NH4-RHO were synthesized in an aqueous ion-exchange media and studied by powder X-ray diffraction. Their thermochemistry was investigated by differential scanning calorimetry and high temperature oxide melt solution calorimetry. The formation enthalpy from binary oxide components of hydrated zeolite RHO varies linearly with the average ionic potential (Z/r) of the extra-framework cations and ranges from −34.46 ± 0.52 kJ/mol for Na,Cs-RHO to −16.75 ± 0.57 kJ/mol for Cd,Cs-RHO. The formation enthalpies for dehydrated zeolite RHO range from −25.49 ± 0.64 kJ/mol for Na,Cs-RHO to +4.12 ± 0.99 kJ/mol for Li,NH4-RHO. These values do not vary linearly with average ionic potential but do show a linear relationship with distortion parameter.

We performed a density functional theory (DFT) study on X-ray photoelectron (XPS) and absorption (XAS) spectra of graphitic carbon nitride (g-C3N4) nanosheets at the N and C K-edges. A combined cluster-periodic approach was employed to calculate XPS spectra, in which the core ionic potential (IP) of the solid 2D material was computed by subtracting the work function (obtained with periodic conditions) from the gas phase IP (obtained with large cluster models). With amino-terminated supermolecules of different sizes, we obtained convergent spectra and provide new assignments for 5 nitrogen [1 sp2; 4 sp3 (bridging, tertiary, and primary/secondary amino nitrogens)] and 4 carbon (all bonded with three nitrogens) local structures. A good agreement with experiments was obtained, with the N1s (C1s) main peak position differing by 0.1-0.2 eV (0.5-0.8 eV). Our simulations show that N1s XPS of pure g-C3N4 contains only two major features at 398.6 and 401.2 eV, contributed from sp2-N and sp3-N, respectively. The chemical shifts of all sp3-N are so close (deviating by 0.3-0.6 eV) that terminal amino groups -NHx (x = 1, 2) will only be distinguished in high-resolution measurements. In C1s XPS, all carbons show similar (deviation < 0.2 eV) IPs, as determined by the same nearest neighbors. We further excluded the effect of shake-up satellites that may change our XPS interpretations by equivalent core hole time-dependent DFT (ECH-TDDFT) simulations. The effect of vibronic coupling is small (redistribution is only 0.1-0.3 eV to the higher-energy region) in the N1s edge as estimated from the asymmetric main peak shape, and negligible in the C1s edge. Quicker size convergence was found in XAS than XPS. In N1s XAS, we identified a weak π* spectral feature at 400-401 eV for both -NHx and tertiary nitrogens. Our study provides a clear theoretical reference for X-ray spectral fingerprints of different local structures, which is useful for analysis of g-C3N4 based materials with various designed or unavoidable structural modifications. We also highlight our combined cluster-periodic approach in calculating the K-edge XPS spectra of general 2D materials which predicts accurate absolute values.

We have successfully synthesized four fused hybrid diimide and diamide arrays with different effective conjugation lengths of perylene diimides and isoindigos. These arrays with varying numbers of amides and imides are an efficient strategy to fine-tune the opto-electronic properties, conformation, energy levels and device performance. It is shown that additional fused isoindigos lead to much lower electron affinity with no influence on the ionic potential. The impact of adding different additional central electron deficient isoindigos to the fused arrays has also been investigated systemically. PDI-BDOPV-PDI incorporating a strong electron deficient BDOPV unit with enforced coplanarity exhibits a very low lowest unoccupied molecular orbital (LUMO) level of −4.11 eV, and the absorption spectrum of PDI-DPN-PDI was even extended to 1000 nm. Thin film transistors were fabricated with these arrays as the semiconductor layers, the fused arrays display electron transport behaviors.

Lithium-salt-based deep eutectic solvents, where the only cation is Li+, are promising candidates as electrolytes in electrochemical energy-storage devices like batteries. We have performed broadband dielectric spectroscopy on three such systems, covering a broad temperature and dynamic range that extends from the low-viscosity liquid around room temperature down to the glassy state approaching the glass-transition temperature. We detect a relaxational process that can be ascribed to dipolar reorientational dynamics and exhibits the clear signatures of glassy freezing. We find that the temperature dependence of the ionic dc conductivity and its room-temperature value also are governed by the glassy dynamics of these systems, depending, e.g., on the glass-transition temperature and fragility. Compared to the previously investigated corresponding systems, containing choline chloride instead of a lithium salt, both the reorientational and ionic dynamics are significantly reduced due to variations of the glass-transition temperature and the higher ionic potential of the lithium ions. These lithium-based deep eutectic solvents partly exhibit significant decoupling of the dipolar reorientational and the ionic translational dynamics and approximately follow a fractional Debye-Stokes-Einstein relation, leading to an enhancement of the dc conductivity, especially at low temperatures. The presented results clearly reveal the importance of decoupling effects and of the typical glass-forming properties of these systems for the technically relevant room-temperature conductivity., Comment: 12 pages, 8 figures. Revised version as accepted for publication in J. Chem. Phys

In this work, we demonstrate the fundamental relationships between stability constants and periodic, acid-base, and structural parameters for complexes of some 1,3-diketones. The four analogues of hexafluoroacetylacetone-2-thenoyltrifluoroacetone, 2-furoyltrifluoroacetone, benzoyltrifluoroacetone, and 2-naphthyltrifluoroacetone-have been studied as chelating ligands for 16 rare-earth metals (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in aqueous solutions. Systems have been investigated spectrophotometrically using a multiwave nonlinear least-squares regression algorithm for data processing. Conditional stability constants were obtained for a wide pH region (2.0-5.4) at constant ionic strength (I = 0.5 M, NaCl). To receive the apparent ("true") equilibrium parameters, acid-base and keto-enol characteristics of the studied ligands have been described and revised for specific conditions. Dissociation constants were obtained in citrate-phosphate buffer media and protonation parameters were received in concentrated hydrochloric acid by the Cox-Yates method. The apparent formation constants for monocomplex species were obtained as thermodynamic invariants (depend only on the temperature) for each ligand and lie from 4.2 to 12.7 logarithmic units. Although the studied ligands have similar values of pKa, the stabilities of their complexes vary considerably. Systematic analysis of 64 apparent stability constants demonstrates that the force of interaction between the metals and nonsymmetric β-diketones increases as 2-furoyltrifluoroacetone < 2-thenoyltrifluoroacetone < benzoyltrifluoroacetone < 2-naphthyltrifluoroacetone. The studied ligands display varying degrees of the correlation between the periodic parameters and formation constants. Naphthyltrifluoroacetone and its complexes with heavy lanthanides exhibit a clear trend in properties with increasing ionic potential. In general, the received set of data can be described from purely electrostatic grounds within the framework of the periodic law. Spectral, keto-enol, acid-base, and complexing properties were reproduced using density functional theory modeling and explain some of the regularities discovered.

EDTA can complex with radionuclides (RNs) to form negatively charged complexes, making it difficult for clay minerals to retard the diffusion of RNs waste. The diffusion coefficient of RNs in water (Dw) is an important parameter for the safety assessment of the repository. In this study, the effectsof EDTA on the diffusion of metal ions (Cu2+, Sm3+, Nd3+, Lu3+ and Zn2+) were investigated by a capillary method. The experimental results showed that [Cu-EDTA]2-, [Sm-EDTA]-and [La-EDTA]-have higher Dw thanthe Mn+. Whereas, [Nd-EDTA]-and [Zn-EDTA]2- have lower Dw than Nd3+ and Zn2+ cations. The Dw is consistent with the literatures, indicating the validity of the capillary method to determine the diffusion coefficients. According to Stokes-Einstein relation, the ionic radius and ionic potential of the ion are in disproportional to the Dw value. Cu-, Sm-and La-EDTA complexes have smaller molecular size than the uncomplexed metal ions, indicating that the Mn+ ions might be associated with many water molecules to form hydrated ions with larger ionic radius. Whereas the [Nd-EDTA]-and [Zn-EDTA]2- have larger molecular size than Nd3+ and Zn2+ cations.

Despite the fact that aluminum is one of the most commonly-used elements, experimental results on the value of its surface tension are largely scattered due to the high sensitivity of aluminum to the atmospheric conditions, leading to huge experimental challenges. In this study, the surface tension of pure Al and Al-O systems was studied in detail using Molecular Dynamics (MD) simulations. A force field that includes embedded atoms method and charge transfer ionic potential was applied to account for interatomic interactions. Simulations were performed at different temperatures (1000-2200 K) with different initial oxygen contents. The simulations allowed us to elucidate the effects of well-controlled atmospheric conditions on surface tension. Our results show that the surface tension of aluminum is sensitive to the amount of oxygen content at the surface, which depends on the total oxygen content and the temperature. At different temperatures, different amounts of oxygen atoms are needed to saturate the aluminum surface ( XSAT0 ). A relationship between XSAT0 and temperature was derived. Due to the scattered data in the literature, a new experiment was performed to measure the surface tension of pure aluminum at two different temperatures. Our MD simulations show a good agreement with these experimental results. We believe that this study can shed light on the underlying mechanisms controlling surface tension of aluminum and could offer routes to better engineer the surface properties of this liquid metal.

Banwarilal Bhalotia College, Asansol-713 303, West Bengal, India Department of Chemistry, Sidho-Kanho-Birsha University, Purulia-723 104, West Bengal, India E-mail: jayantajune@gmail.com Manuscript received online 05 December 2020, revised and accepted 29 December 2020 Borosilicate glasses loaded with uranium have been prepared for immobilization nuclear waste. In our work we melt the glass batches at in the temperature range from 800–900ºC and soaked for 90 min to achieve homogeneity of the glass. We study the pH of the leachate and it was ranging from 6.18 up to 7.45 under different time. We performed the Leaching behavior the sample glasses in a apparatus called Soxhlet with a maximum time period of 200 h with distilled water. Weight losses of the glasses were measured electronic balance with time interval. Residual activities were followed by ‘Radiotracer technique’ with cumulative time period for leaching. Leaching rate is calculated by measuring the surface area of the leached glass samples. The findings are 4.14×10–4 and 8.26×10–3 (in g.m–2.h–1) respectively at 90ºC. The result are explained with ionic potential value (the ionic charge/ionic radii) of modifier doped in glass structure. Leaching studies are important because waste glasses have to be kept under ground for a very long time period.

International audience; Nanoporous graphene displays salt-dependent ion permeation. In this work, we investigate the differences in Donnan potentials arising between reservoirs, separated by a perforated graphene membrane, containing different cations. We compare the case of monovalent cations interacting with nanoporous graphene with the case of bivalent cations. This is accomplished through both measurements of membrane potential arising between two salt reservoirs at different concentrations involving a single cation (ionic potential) and between two reservoirs containing different cations at the same concentration (bi-ionic potential). In our present study, Donnan dialysis experiments involve bivalent MgCl 2 , CaCl 2 , and CuCl 2 as well as monovalent KCl and NH 4 Cl salts. For all salts, except CuCl 2 , clear Donnan and diffusion potential plateaus were observed at low and high salt concentrations, respectively. Our observations show that the membrane potential scaled to the Nernst potential for bivalent cations has a lower value (≈50%) than for monovalent cations (≈72%) in the Donnan exclusion regime. This is likely due to the adsorption of these bivalent cations on monolayer graphene. For bivalent cations, the diffusion regime is reached at a lower ionic strength compared to the monovalent cations. For Mg 2+ and Ca 2+ , the membrane potential does not seem to depend upon the type of ions in the entire ionic strength range. A similar behavior is observed for the KCl and NH 4 Cl membrane potential curves. For CuCl 2 , the membrane potential curve is shifted toward lower ionic strength compared to the other two bivalent salts and the Donnan plateau is not observed at the lowest ionic strength. Bi-ionic potential measurements give further insight into the strength of specific interactions, allowing for the estimation of the relative ionic selectivities of different cations based on comparing their bi-ionic potentials. This effect of possible ion adsorption on graphene can be removed through ion exchange with monovalent salts.

Numerous countries have shown signs of environmental pollution to prioritize economic growth and benefits, leading to seriously contaminated waters. This work indicated the method to synthesize a green material, which could remove contaminants to protect the natural environment. The porosity and functionality effects of amine-functionalized activated carbon (AFAC) enhanced the removal of toxic heavy metals (THMs) in aqueous solution. The raw activated carbon (RAC) was thermally modified with ultrahigh pure nitrogen (UHPN) at 500°C and 1000°C and then amine-functionalized with coupling agent of aminopropyltriethoxysilane (APS). They were denoted as AFAC-5 and AFAC-10, respectively. The data showed an enhanced metal adsorption capacity of the AFACs, because the modification produced more desired porosity and increased amine functional groups. AFAC-10, modified at a higher temperature, showed much higher THM adsorption capacity than AFAC-5, modified at a lower temperature, and RAC. The adsorption capacity decreased in the following order: Ni > Cd > Zn, which was in good agreement with the increasing electronegativity and ionic potential and the decreasing atomic radius. The maximum THM adsorption capacity of AFAC-10 for Ni, Cd, and Zn was 242.5, 226.9, and 204.3 mg/g, respectively.

The utility of multivalent metal ions with aqueous electrolyte increases the electrochemical performances of supercapacitors. These compounds are non- toxic, low cost and provide accessible ionic potential towards the application’s scenario. Herein, we report a facile and effective combination of magnesium and iron layered double hydroxides (L-MFH) synthesized by industrially applicable electrodeposition technique. As of now, the bulky compositions between the metals, poor ionic conductivity and deteriorated nanostructure limits the innovation in supercapacitors. Interestingly, L-MFH dendritic structure delivers high specific capacity, 610 Cg−1 at 10 mV/s in 1 M NaOH electrolyte. The derived material retains 80% specific capacity over 3000 cycles, further the asymmetric device through the combination of L-MFH//ACC (activated carbon cloth) delivered a high energy and power densities of 39.86 Whkg−1 and 1206.03 Wkg−1, respectively. Our prescribed methodology encourages the reliability of electrode preparations, which promotes high performances of many hybrid devices.

Ash fusion temperatures (AFTs) are widely employed to evaluate petroleum coke ash fusibility, which has significant effects on its high-value and clean utilization. Sodium (Na) and potassium (K) both are considered to be the effective components to improve the ash fusion characteristics for slag tapping of entrained flow gasifiers. Herein, the effects of (Na2O + K2O) and Na2O/K2O mass ratio on the fusion behaviors of petroleum coke ash with high vanadium (V) and nickel (Ni) were investigated by AFTs tests in conjunction with X-ray diffraction and thermodynamic equilibrium calculations. The results demonstrated that AFTs followed a significant decline with the increase in (Na2O + K2O) content. Vanadium trioxide (V2O3), coulsonite (FeV2O4), nickel (Ni) and nepheline ((Na,K)AlSiO4) were the dominant crystalline minerals formed in high-temperature ash. The formation of low-melting (Na,K)AlSiO4 was responsible for the variation in AFTs because of the low ionic potential of Na+ and K+. AFTs dropped slightly as the Na2O/K2O mass ratio decreased from 10/0 to 4/6, and then exhibited a sharp rise. The mixed alkaline effect between Na and K effectively influenced the AFTs variations. When the Na2O/K2O mass ratio was higher than 8/2, Na existed in eutectics or amorphous matters rather than Na-bearing crystalline species at high temperatures. As the Na2O/K2O mass ratio further decreased, the crystalline phase (Na,K)AlSiO4 was converted into high-melting leucite (KAlSi2O6), which resulted in the sharp increase in AFTs.

Three transition metal ions (Ni2+, Fe2+ and Cu2+)were chosen as dopants to fabricate PPy/M2+ (M:Ni2+, Fe2+ and Cu2+) electrodes by cyclic voltammetry on the stainless steel wire mesh. Fourier transform infrared, X-ray diffraction, Scanning electron microscopy and X-ray photoelectron spectroscopy techniques were employed to characterize the structure and morphology of PPy/M2+. The results prove that there are some changes in microstructure and valence of transition metal ions. Cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy tests in 1.0 mol L−1 HNO3 electrolyte in three-electrode system exhibit that the larger specific capacitance of PPy/M2+ electrodes are 517, 679 and 764 F g−1 at a current density of 5 mA cm−2 and the capacitance’ retention is 80.5, 82.7 and 83.8% after 1000 cycles. Besides, it was found that the different electrochemical properties of PPy/M2+ electrodes related to different ionic nature, such as ionic potential and ionic radius.

Electric field driven ion transport in ion exchange membranes, often quantified by membrane resistance or ionic conductivity, is important for membrane-based technologies such as electrodialysis, batteries, fuel cells, etc. Various methods for measuring membrane ionic conductivity have been reported in the literature, but no widely accepted, standard protocol exists. Consequently, conflicting ionic conductivity results for widely studied commercial ion exchange membranes have been reported, leading to confusion regarding, for example, the salt concentration dependence of membrane ionic conductivity, especially for membranes equilibrated with dilute aqueous salt solutions. In this study, we report a simple, fast, reliable technique for measuring ionic conductivity based on direct contact between the membrane and electrodes. The technique was used to measure ionic conductivity values for a series of commercial ion exchange membranes as a function of external solution NaCl concentration (ranging from 0.001 to 5 M). The salt concentration dependence of membrane ionic conductivity was rationalized within the Nernst-Einstein framework. At low external solution salt concentrations ( 0.3 M), ionic conductivity values increased with increasing salt concentration for three of the membranes, presumably due to increased ion sorption owing to weaker Donnan exclusion, and decreased for one membrane, presumably due to decreased ion diffusion coefficients resulting from osmotic deswelling.

The process for separating and purifying lithium in brines based on electrodialysis with monovalent selective ion exchange membranes was investigated in our previous work. The migration of coexisting cations in brines was competitive with lithium ions, especially monovalent cations (Na+ and K+). The aim of this study was to examine the influence of major coexisting cations in brines on lithium recovery in the selective-electrodialysis (S-ED) process. Considering the factors of coexisting cations, such as concentration and type, some migration laws of lithium ion were found as follows: the concentration of coexisting cations had negative effect on the migration of lithium ion; the influence order of coexisting cations on lithium migration was contrary to their hydrated radius sequence: K+>Na+>Ca2+>Mg2+. In order to characterize the migration process of cations through monovalent selective cation exchange membrane in microcosmic theory, a partial dehydration conceptual model based on charge capillary column theory and ionic potential was proposed. And the model was used to characterize the ions migration process. Simultaneously, considering the hydration potential which indicates how strongly an ion would attract water molecules, the influence sequence of coexisting cations was explained legitimately. These observations might provide some theoretical basis and technological support for the relevant research of recovering lithium from brines.

UV-Visible spectrophotometry was used to study the influence of Mg(II) and Ca(II) ions on caffeic acid (CA) autoxidation in weakly alkaline aqueous solution. While the autoxidation rate was very slow in the absence of metal ions, both Mg(II) and Ca(II) ions greatly enhanced the autoxidation rate. Determination of the spectral and concentration profiles of the individual components involved in the CA autoxidation processes in the presence of metal ions was performed using multivariate curve resolution-alternating least squares (MCR-ALS) analysis of spectrophotometric data. MCR-ALS analysis supported by the quantum chemical calculations of electronic absorption spectra for possible initial reaction products showed that CA autoxidation in the presence of Mg(II) and Ca(II) ions proceeds by the instant formation of CA–metal complexes followed by the almost simultaneous formation of CA quinone anions and various CA dimers and the final transformation into polymeric, humic acid-like, products. Also, the MCR-ALS analysis revealed that the effect of Mg(II) ions was more pronounced at the initial stage of autoxidation. The differences in the influence of Mg(II) and Ca(II) ions on the CA autoxidation may be attributed to the stronger metal ion–ligand interaction for Mg(II) ions caused by their larger ionic potential in comparison to Ca(II) ions. The results of this study may be important for better understanding of the interactions of Mg(II) and Ca(II) ions with natural phenolic food antioxidants and thus significant for understanding their activities in real systems and optimization of conditions for the processing and/or storage of certain types of foods.

The liquidus temperature (Tliq) of coal ash is above the temperature at which the last solid phase disappeared. Tliq of coal ash slag is widely used to evaluate ash fusion and flow behaviors. The method of determining the liquidus temperature is based on phase equilibrium, the activation energy of viscous flow and chemical composition models. In this work, a linear relation between average molar ionic potential (Ia) and potential energy (Pe) as well as Tliq and potential energy is supported by molecular dynamics simulations. We correlated Tliq (derived from thermodynamic equilibrium calculation) and the molar ionic potential of the chemical composition. The linear relation between coal ash composition and the Tliq is established for the first time, with T liq = ( 170.43 - 3.1457 × I a ) × S / A + 15.725 × I a + 360.78 (DE

Sarcheshmeh mine is one of the largest Oligo-Miocene porphyry Cu deposits in the world. It is located in the Kerman Cenozoic magmatic arc in southeastern Iran. This paper discusses the geo-environmental behavior of rare earth elements (REEs) in the Sarcheshmeh dammed tailing pond, situated in semiarid climate. For this purpose, solid and water samples were collected to consider: (1) weathering/oxidation reactions and upward migration of soluble elements; (2) super-saturation and formation/dissolution of the secondary evaporative phases; (3) hydro-geochemical changes of the surface and groundwater resources; (4) flotation of the Cu-sulfide ore and tailing management strategies. The mean values of the ∑ REEs for fresh and weathered tailings and the evaporative phases were 113.0, 103.7 and 74.6 mg/kg, respectively. When compared with the fresh and weathered tailings, the evaporative phases showed significant enrichment of HREEs and a well-depleted pattern of LREEs (except for that of Eu). This geochemical pattern suggests a higher solubility and mobility potential of HREEs and Eu compared with LREEs, resulting in good fractionation and enrichment of these elements in the surface evaporative layer formed on top of the weathered tailings. The water samples showed a range of hydro-geochemical features under acidic (pH of 2.5 to 4.7), near neutral (pH of 6.4 to 7.9), alkaline (pH of 8 to 10) and highly alkaline (pH > 10) conditions. The maximum concentration of REEs was observed in the acidic waters produced by the weathered tailings after rainfall (∑ REEs of 489 to 1903 μg/L). Although ∑ REEs decreased as the pH value increased, the general trend was compatible with the highest concentration of HREEs rather than LREEs. The speciation calculations indicate that LnSO4+, Ln(SO4)2− and Ln3 + are the primary forms of dissolved REEs at acidic and near neutral pH and the dominant species was LnSO4+. LnCO3+ (40.78%), Ln(CO3)2− (31.68%) and LnSO4+ (31.07%) were the dominant species under alkaline conditions. At high alkaline pH, the speciation pattern changed to LnOH2 + (53.15%), Ln(CO3)2− (44.88%) and LnCO3+ (2.61%), where Ln denotes lanthanide. Based on the results and considering previous works, it appears that ionic potential plays an important role in the geo-environmental behavior of REEs of adsorption tendency, mobility potential and ionic substitution.

Despite the fact that aluminum is one of the most commonly-used elements, experimental results on the value of its surface tension are largely scattered due to the high sensitivity of aluminum to the atmospheric conditions, leading to huge experimental challenges. In this study, the surface tension of pure Al and Al-O systems was studied thoroughly using Molecular Dynamics (MD) simulations. A force field that includes embedded atoms method and charge transfer ionic potential was applied to account for interatomic interactions. To complement and validate the numerical approach, the surface tension of pure aluminum at two different temperatures was also measured. A good agreement was obtained between the measured and predicted surface tension. Simulations were then performed at different temperatures (1000–2200 K) with different initial oxygen contents to elucidate the effects of well-controlled atmospheric conditions on surface tension. Our results also show that the surface tension of aluminum is sensitive to the amount of oxygen content at the surface, which depends on the total oxygen content and the temperature. At various temperatures, different amounts of oxygen atoms are needed to saturate the aluminum surface ( X O Sat . ) . A relationship between X O Sat . and temperature was derived. We believe that this study can shed light on the underlying mechanisms controlling surface tension of aluminum and could offer routes to better engineer the surface properties of this liquid metal.