Uptake of heavy metal ions from aqueous solution using Mg–Al layered double hydroxides intercalated with citrate, malate, and tartrate

Mg–Al layered double hydroxide (Mg–Al LDH) was modified with organic acid anions using a coprecipitation technique, and the uptake of heavy metal ions from aqueous solution by the Mg–Al LDH was studied. Citrate·Mg–Al LDH, malate·Mg–Al LDH, or tartrate·Mg–Al LDH, which had citrate³⁻ (C₆H₅O₇³⁻), malate²⁻ (C₄H₄O₅²⁻), or tartrate²⁻ (C₄H₄O₆²⁻) anions intercalated in the interlayer, was prepared by dropwise addition of a mixed aqueous solution of Mg(NO₃)₂ and Al(NO₃)₃ to a citrate, malate, or tartrate solution at a constant pH of 10.5. These Mg–Al LDHs were found to take up Cu²⁺ and Cd²⁺ rapidly from an aqueous solution at a constant pH of 5.0. This capacity was mainly attributable to the formation of the citrate–metal, malate–metal, and tartrate–metal complexes in the interlayers of the Mg–Al LDHs. The uptake of Cu²⁺ increased in the order malate·Mg–Al LDH < tartrate·Mg–Al LDH < citrate·Mg–Al LDH. The uptake of Cd²⁺ increased in the order malate·Mg–Al LDH < tartrate·Mg–Al LDH = citrate·Mg–Al LDH. These differences in Cu²⁺ and Cd²⁺ uptake were attributable to differences in the stabilities of the citrate–metal, malate–metal, and tartrate–metal complexes. These results indicate that citrate³⁻, malate²⁻, and tartrate²⁻ were adequately active as chelating agents in the interlayers of Mg–Al LDHs.     

Special features of synthesis of a heat-resistant glass-ceramic coating

In order to protect Ni–Cr alloys from high-temperature corrosion, a new heat-resistant glass-ceramic coating was developed with a glass matrix synthesized on the basis of a composite R _x O–Al₂O₃–SiO₂–TiO₂ (R–Li^–, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺) system. The special features of the formation of crystalline phases in the glasses in heat treatment and the optimum regime for the formation of a glass ceramic structure are described.Translated from Steklo i Keramika, No. 3, pp. 30–32, March, 1996.     

Kinetics and Mechanism of the Interaction of Alkali Calcium Silicate Glasses with Salt Melts in the KNO3–Pb(NO3)2 System

The interaction of alkali calcium silicate glasses with salt melts in the KNO₃–Pb(NO₃)₂ system is investigated at temperatures of 420–520°C. The chemical composition of crystalline coatings formed upon treatment contains both components of the initial glass (SiO₂, 9–12 wt %; CaO, 0.8–1.2 wt %) and components of the salt melt (PbO, 82–89 wt %). The treatment temperature is the main factor affecting the structure of the modified surface layer. The mechanism of the interaction of alkali calcium silicate glasses with salt melts is analyzed. According to this mechanism, the interaction involves the ion exchange (with the participation of Na⁺, K⁺, Ca²⁺, and Pb²⁺ ions), crystallization of modified surface layers, and incorporation of Pb _x O _y nanoparticles (formed in the salt melt) into the coating structure.     

Composition and properties of chrome spinels separated by acids from kimpersai rocks

Conclusions We investigated compositions, properties and structure of elementary nuclei for Kimpersai chrome spinels, separated by acids from rocks of 6 new sources in Kazakhstan.The chemical composition of chrome spinels is relatively constant and close to the stoichiometric, with R₂O₃: RO changing from 0.9 to 1.2.According to the classification given in [13]they are related to magnesia chromites (Mg, Fe) Cr₂O₄ The properties of chrome spinels change with their composition almost linearly. The melting temperature of the chrome spinel is 2050–2060°, that is, they are highly refractory materials and valuable raw materials for the production of new types of refractories.The x ray defraction method established that in the Kimpersai chrome spinels the ordinary crystalline structure is predominant. The bivalent cations of magnesium and iron are located in the tetrahedral form and the trivalent cations of chromium, aluminum and iron in the octahedral. In the elementary nucleus of such chrome-spinels the cations are distributed in the following manner: 5–6 ions Mg²⁺ and 2–3 ions Fe²⁺ are located in the tetrahedral, and 12–13 ions Cr³⁺, 2–3 ions Al³⁺, and 1 ion Fe³⁺ in the octahedral. The oxygen parameter for Kimpersai chrome spinels is somewhat greater than the value for the ideal spinel structure, which can be explained by the expansion of the tetrahedral gaps and the compression of the octahedral.Translated from Ogeupory, No.8, pp. 29–36, August, 1966.     

Electrode reaction of the Np3+/Np couple in LiCl–KCl eutectic melts

The electrochemical behaviour of the Np³⁺/Np couple in the LiCl–KCl eutectic salt was investigated by electromotive force measurements, cyclic voltammetry and chronopotentiometry in the temperature region between 723 and 823 K. The standard redox potential of the Np³⁺/Np couple vs Ag/AgCl (1.00 wt %) was measured and given by the equation, E _Np ³⁺ _/Np ^° = –2.0298 + 0.000706 T, where E is in V and T in K. The electrode reaction of the Np³⁺/Np couple was almost reversible under the conditions studied. The diffusion coefficient of Np³⁺, D _Np ³⁺, in the LiCl–KCl eutectic melts between 723 and 823 K was represented by the equation, D _Np ³⁺ = 2.22 × 10^–6 – 6.88 × 10^–9 T + 5.60 × 10^–12 T ² cm² s^–1. The adsorption and desorption peaks of Np at the Mo working electrode caused by underpotential deposition were also observed in the cyclic voltammograms, and the work function of Np was evaluated as 3.04 eV by peak analysis of the cyclic voltammograms.     

On the Possibility of Forming Complexes with the Participation of O2– Ions in Melts and Glasses of the Na2O–SiO2–Cu2O System

The structural role of copper ions in melts (glasses) of the Na₂O–SiO₂–Cu₂O–CuO system is analyzed in the framework of the acid–base concept with due regard for the geometric (the radius ratio for Cu²⁽¹⁾⁺ and O^2– ions) and energy (the mean enthalpies of the Cu²⁽¹⁾⁺–O bonds) factors. It is demonstrated that copper ions in the structure fulfill the function of modifier cations. In these melts, the Cu¹⁺–Cu²⁺ redox equilibrium can be described without regard for the formation of [Cu²⁽¹⁾⁺O_4/2]^2(3)– ionic complexes (which could be incorporated into the structure of silicon–oxygen anions) and [Cu²⁺O _b/k ]^{2 – b/k} polyhedra providing the interaction between Cu²⁺ ions and anions. The influence of the formation of these polyhedra on the redox equilibrium is considered within the formalism of chemical thermodynamics. The composition dependence of the oxygen ion exponent pO is measured by an electromotive force (emf) technique. The ratio between the numbers of copper atoms with different valences is determined by chemical analysis. The experimental data obtained are in agreement with the theoretical inferences.     

Dissolution kinetics of dehydroxylated nickeliferous goethite from limonitic lateritic nickel ore

The dissolution kinetics in 2 M H₂SO₄ of variously dehydroxylated nickeliferous goethites was investigated for five oxide-type lateritic nickel deposits. Goethite was the main constituent with minor amounts of quartz, talc, kaolinite and Mn oxides. Dissolution of Fe from heated materials followed the Kabai equation. There was a 9–34-fold increase in the Kabai dissolution rate constant (k) for samples heated at 340–400 °C due to both the increased surface area (1.5–2.6 fold) and higher density of structural defects (5–10 fold) in the variously dehydroxylated products. The presence of structural Al and Cr in goethite appears to reduce dissolution rate possibly through the greater M³⁺–OH, O bond strength relative to Fe³⁺, Ni²⁺–OH, O. Nickel showed congruent dissolution with Fe indicating that Ni was uniformly incorporated in the goethite structure. Pre-heating goethite to 600–800 °C for 30 min resulted in incongruent dissolution of Fe and Ni. It is postulated that some Ni is ejected from the neo-formed hematite structure and resides on the crystal surface or in voids. These results may contribute to the development of more efficient procedures for Ni extraction including heap leaching of lateritic nickel ores.     

Preservation of dolomite powders

Conclusions The preservative action depends on the angle of contact between the powder and the liquid: The smaller the angle of contact, the better is the preservation. The required oiling of the powder is obtained with 3–5% of preservative.Unroasted dolomite powders (apparent densities 1.86–2.3 g/cm³) are hardly affected by the preservative. Partly roasted dolomite (apparent density 2.78 g/cm³) is affected only by a preservative with a small angle of contact.Properly roasted dolomite is satisfactorily preserved; the preservative reduces the tendency to hydration during storage, and practically eliminates dust particles by agglomerating them.Oiling the powders does not impair their sintering adhesion to magnesite brick.As a result of our investigations, a project has been developed for technological instruction on the oiling of dolomite powders.Translated from Ogneupory, No. 1, pp. 31–35, January, 1979.     

Cation composition during recrystallization of layered double hydroxides from mixed (Mg, Al) oxides

Changes in cation composition and M²⁺/M³⁺ ratio during hydrotalcite regeneration were studied. Regenerated hydrotalcites were obtained by recrystallization of mixed (Mg, Al) oxides in solutions of divalent (Mg, Zn, Co, Ni, Cu) or trivalent (Al, Fe) cations.Heating Mg–Al–CO₃ hydrotalcites with Mg/Al=2, 3 and 3.7, at 600 °C for 2 h yielded periclase-like mixed (Mg, Al) oxides (HT-P). The hydrotalcite structure was restored by dispersing oxides 48 h in water or aqueous solutions of different cations.The presence of Mg²⁺, Zn²⁺, Ni²⁺, Co²⁺, Cu²⁺ salts or of low soluble hydromagnesite increased the M²⁺/Al ratio, reaching a maximum value of 3.8. An incorporation of Zn²⁺, Ni²⁺, Co²⁺ and Cu²⁺ cations in the newly formed hydrotalcite was detected, while Mg²⁺ remained in solution. In the presence of soluble Al salts or freshly precipitated Al(OH)₃, the M²⁺/Al ratio approximated the minimal possible value of 2.The Mg/Al ratio of a hydrotalcite crystallized from a mixture of two HT-P samples with different Mg/Al ratios is equal to the weighted average value.The results obtained support the conception of the dissolution–crystallization mechanism of hydrotalcite regeneration from mixed (Mg, Al) oxides contrary to the widely accepted concept of topotactic processes.     

Firing Lis'Egorsk dolomite in rotary furnace

Conclusions By calcining Lis'egorsk dolomite in a rotary furnace by the dry method (0–25 mm fraction) with 3–3.5%clinker we obtained high-grade dolomite powder with an apparent density of 3.3 g/cm³.Industrial tests of the burned dolomite showed that it is suitable as a fettling material for open-hearth furnaces.     

Thermal behaviour of Cu–Mg–Mn and Ni–Mg–Mn layered double hydroxides and characterization of formed oxides

Thermal behaviour of synthetic Cu–Mg–Mn and Ni–Mg–Mn layered double hydroxides (LDHs) with M^II/Mg/Mn molar ratio of 1:1:1 was studied in the temperature range 200–1100 °C by thermal analysis (TG/DTA/EGA), powder X-ray diffraction (XRD), Raman spectroscopy, and voltammetry of microparticles. Powder XRD patterns of prepared LDHs showed characteristic hydrotalcite-like phases, but further phases were indirectly found as admixtures. The Cu–Mg–Mn precipitate was decomposed at temperatures up to ca. 200 °C to form an XRD-amorphous mixture of oxides. The crystallization of CuO (tenorite) and a spinel type mixed oxide of varying composition Cu_xMg_yMn_zO₄ with Mn⁴⁺ was detected at 300–500 °C. At high temperatures (900–1000 °C), tenorite disappeared and a consecutive crystallization of 2CuO·MgO (gueggonite) was observed. The high-temperature transformation of oxide phases led to a formation of Cu^I oxides accompanied by oxygen evolution. The DTA curve of Ni–Mg–Mn sample exhibited two endothermic effects characteristic for hydrotalcite-like compounds. The first one with minimum at 190 °C can be ascribed to a loss of interlayer water, the second one with minimum at 305 °C to the sample decomposition. Heating of the Ni–Mg–Mn sample at 300 °C led to the onset of crystallization of oxide phases identified as Ni_xMg_yMn_zO₄ spinel, (Ni,Mg)O oxide containing Mn⁴⁺ cations, and easily reducible XRD-amorphous species, probably free Mn^III,IV oxides. At 600 °C (Raman spectroscopy) and 700 °C (XRD), the (Ni,Mg)₆MnO₈ oxide with murdochite structure together with spinel phase were detected. Only spinel and (Ni,Mg)O were found after heating at 900 °C and higher temperatures. Temperature-programmed reduction (TPR) profiles of calcined Cu–Mg–Mn samples exhibited a single reduction peak with maximum around 250 °C. The highest H₂ consumption was observed for the sample calcined at 800 °C. The reduction of Ni–Mg–Mn samples proceeded by a more complex way and the TPR profiles reflected the phase composition changing depending on the calcination temperature.     

The Nature and Properties of Iron-Containing Nanoparticles Dispersed in an Aluminosilicate Matrix of Cenospheres

The forms of iron in the composition of cenospheres prepared from energy ashes are investigated using the electron paramagnetic resonance (EPR) method, Mössbauer spectroscopy, and thermodynamic analysis. Cenospheres of controlled composition are produced by sieve, gravimetric, and magnetic separation. It is established that iron in two states (Fe³⁺, Fe²⁺) enters into the cenosphere composition. At an Fe₂O₃ content of 3–4 wt %, iron(III) predominantly occurs in two forms: single ions in the glass and particles of the superparamagnetic phase with a spinel structure. These particles are 30–50 Å in size and are dispersed in aluminosilicate glass. The sublattices of the superparamagnetic spinel are diamagnetically diluted with Mg²⁺ and Al³⁺ ions. At an Fe₂O₃ content of higher than 7 wt %, cenospheres also contain a magnetic phase based on defect magnetite.     

Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)]3[α-AsM12O40] (M = Mo/W)

Two super-molecular complexes [Na(DB18C6)(CH₃CN)]₃[α-AsM₁₂O₄₀] (M = Mo/W) were obtained by solvothermal reaction and characterized by IR,¹H ¹³C and gUMBC NMR, X-ray. The result reveals that the complex consists of a [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) anion with α-Keggin structure, and three complex [Na (DB18C6)(CH₃CN)]⁺ cations in which every sodium ion is located in the cavity of dibenzo-18-crown-6 with 6 Na–O bonds and coordinated with one of the terminal O atom of [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) and the N atom of CH₃CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single M₃O₁₃ (M = Mo/W) triplet of the α-Keggin metalatoarsenate anion, and M–O_b (M = Mo/W) bonds exhibit alternating single–double bond character.     

Structure of a methylamine sorption complex of fully dehydrated Cd-exchanged zeolite X, Cd46(CH3NH2)16[Si100Al92O384]-FAU

The structure of a methylamine sorption complex of fully dehydrated, fully Cd²⁺-exchanged zeolite X, Cd₄₆(CH₃NH₂)₁₆[Si₁₀₀Al₉₂O₃₈₄]-FAU (a = 24.863(4) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group at 21(1) °C. An aqueous exchange solution 0.05 M in Cd²⁺ was allowed to flow past the crystal for 5 days. The crystal was then dehydrated at 480 °C and 2 × 10⁻⁶ Torr for 2 days (colorless), and exposed to 160 Torr of methylamine gas at 21(1) °C for 2 h (yellow). Diffraction data were then gathered in this atmosphere and were refined using all data to the final error indices (based upon the 524 reflections for which F_o > 4σ(F_o)) of R₁ = 0.069 and wR₂ = 0.200. In this structure, Cd²⁺ ions occupy three crystallographic sites. The octahedral sites I at the centers of the hexagonal prisms are filled with 16 Cd²⁺ ions per unit cell (Cd–O = 2.369(8) Å). The remaining 30 Cd²⁺ ions are located at two non-equivalent sites II with occupancies of 14 and 16. The 16 methylamine molecules per unit cell lie in the supercage where each interacts with one of the latter 16 site-II Cd²⁺ ions: N–Cd = 2.11(8) Å. The imprecisely determined N–C bond length, 1.49(22) Å, agrees with that in gaseous methylamine, 1.474 Å. The positions of the hydrogen atoms were calculated. It appears that one of the amino hydrogen atoms hydrogen bonds to a 6-ring oxygen, and that the other forms a bifurcated hydrogen bond to this and another 6-ring oxygen. The methyl group is not involved in hydrogen bonding.     

Cation exchange capacity methodology III: Correct exchangeable calcium determination of calcareous clays using a new silver–thiourea method

Cation exchange capacity (CEC) is a fundamental property of clays and soils. Determination of CEC for samples that contain Ca-carbonate minerals, such as calcite and dolomite, is problematic because Ca²⁺ released by dissolution of carbonates during CEC determinations interferes with the accuracy of CEC values. This paper describes a new method for the determination of correct exchangeable Ca²⁺ values of calcareous clays and soils. For the method, a silver–thiourea exchange solution is saturated with Ca²⁺ by treatment with fine-grained calcite prior to the start of the exchange procedure. Using this exchange solution, calcite in the sample can no longer be dissolved but exchangeable Ca²⁺ is desorbed quantitatively. The case for dolomite is similar, because dissolution of dolomite is minimised. However, the determination of reasonable exchangeable Ca²⁺ values for samples containing gypsum is not possible because gypsum is soluble in the exchange solution.     

Influence of the A-site cation in AMnO3+x and AFeO3+x (A = La,Pr, Nd and Gd) perovskite-type oxides on the catalytic activity for methane combustion

The effect of rare-earth ions (La, Pr, Nd and Gd) in AMnO_3+x and AFeO_3+x perovskites on the thermal behavior and on the catalytic activity for the deep oxidation of methane has been studied. AMnO_3+x perovskites showed after preparation an oxidative non-stoichiometry. Oxygen desorption analysis revealed for the four manganites different desorption steps occurring between 930 and 1370 K. Stoichiometry was reached after the first desorption step. Heating the samples at temperatures above 1300 K resulted in phase segregation to the simple oxides. AFeO_3+x perovskites were more stable towards thermal decomposition than the Mn-perovskites, showing no oxygen evolution up to 1400 K. The reducibility of these perovskites in hydrogen correlated inversely with the relative effective ionic radii of the trivalent rare-earth cations. Comparative catalytic studies were carried out in a fixed-bed microreactor at atmospheric pressure in the temperature range 600–1200 K. The activities at 770 K, expressed as reaction rates referred to the BET surface area, varied between 1.4 × 10^–7 and 2.9 × 10^–7 mol s^–1 m^–7 for the AMnO_3+x, and between 1.1 × 10^–7 and 1.6 × 10^–7 mols^–1m^–2for the AFeO_3+x perovskites.     

Synergistic effect of TiO2 and iron oxide supported on fluorocarbon films. Part 1: Effect of preparation parameters on photocatalytic degradation of organic pollutant at neutral pH

Iron oxide and TiO₂ were immobilized on modified polyvinyl fluoride films in a sequential process. Synergic effects of iron oxide and TiO₂ on the polymer film were observed during the heterogeneous degradation of hydroquinone (HQ) in the presence of H₂O₂ at pH close to neutrality and under simulated solar irradiation. Within the degradation period, little iron leaching (<0.5 mg/L) was observed.The surface of commercial polyvinyl fluoride (PVF) film was modified by TiO₂ under light inducing oxygen group (C–OH, CO, COOH) formation on the film surface. During this treatment, TiO₂ nanoparticles simultaneously bind to the film, leading to PVF^f–TiO₂. The possible mechanistic pathway for the TiO₂ deposition and the nature of the polymer–TiO₂ interaction are discussed. Furthermore PVF and PVF^f–TiO₂ were immersed in an aqueous solution for the deposition of iron oxide layer by hydrolysis of FeCl₃, leading to PVF–Fe oxide and to PVF^f–TiO₂–Fe oxide respectively.HQ degradation and mineralization mediated by PVF^f–TiO₂, PVF–Fe oxide and PVF^f–TiO₂–Fe oxide were investigated under different conditions. Remarkable synergistic effects were observed for PVF^f–TiO₂–Fe oxide possibly due to Fe(II) regeneration, accelerated by electron transfer from TiO₂ to the iron oxide under light.     

Comparative Study of the Synthesis and Properties of Polyoxometalate Pillared Layered Double Hydroxides (POM-LDHs)

The pillaring of (NO₃)-ZnAl-LDHs with the polyoxometalates (POMs) [PV₂W₁₀O₄₀]^5–, [Mo₇O₂₄]^6–, [V₁₀O₂₈]^6– and [H₂W₁₂O₄₀]^6–, using large organic anions like terephthalate for pre-swelling the LDH structure forms a promising method for the controlled creation of small micropores. The use of the terephthalate precursor ((T)-ZnAl-LDH) avoided almost completely the formation of undesired side phases during pillaring, although anion exchange with the large POM complexes proceeded with more difficulty than in the case where (NO₃)-LDHs were used as a starting material. Direct pillaring via the (NO₃)-LDHs resulted in multiphased materials, and no correlation was found between the M(II)/M(III) ratios in the starting LDHs and the created porosity. For the [POM]-ZnAl-LDHs pillared via the terephthalate precursor, the layer charge density arising from the amount of isomorphically substituted Al³⁺ in the LDH layers forms the crucial parameter with regard to the created microporosity. Improving the surface area (SA) and micropore volume (PV) values was accomplished by lowering the charge density on the LDH layers (increasing the Zn²⁺/Al³⁺ ratio). In this way, a [PV₂W₁₀O₄₀]-ZnAl-LDH (Zn²⁺/Al³⁺ = 4.26) with a SA (BET) of 166 m²/g and a PV of 0.047 cm³/g was formed.For the different types of pillars, small micropores were formed due to the pillaring process. In the case of the smaller POM complexes [Mo₇O₂₄]⁶⁺ and [V₁₀O₂₈]⁶⁺, an increase in PV and SA was not accompanied by a detectable shift in average pore size, which was the case for the second group of complexes, [PV₂W₁₀O₄₀]^5– and [H₂W₁₂O₄₀]^6–. Due to their larger dimensions, mainly micropores between 0.71 and 1.06 nm were created at high Zn²⁺/Al³⁺ ratios, together with a substantial amount of pores smaller than 0.71 nm.     

Redox chemistry of H2S oxidation by the British gas Stretford process part V: Aspects of the process chemistry

Stretford processes use air to oxidize H₂S in process and natural gases to elemental sulphur, by absorption in aqueous solution at about pH 9 and reaction of the resulting HS^– ions with dissolved oxygen, in the presence of anthraquinone disulphonates (AQDS) and vanadium (v) species, which act as catalysts. Kinetic measurements of the reactions (AQ27DS + HS^– ions), (V(v) + HS^– ions) and (AQ27DSH^– + O₂), primarily used stopped flow spectrophotometry, as reported here, following papers on the electrochemical behaviour of the individual redox couples in Stretford Processes. The course of reaction (AQ27DS + HS^– ions) was also followed with a gold bead indicator electrode, the potential of which was determined essentially by the AQ27DS/AQ27DSH^– couple as the former species were reduced to the latter. Attempts to use⁵¹V NMR to characterize aqueous vanadium-sulphur complexes were inconclusive. A possible mechanism for Stretford Processes is postulated, involving polysulphide (S _n ^2–) ions as intermediates, which are oxidized to elemental sulphur by another intermediate, H₂O₂, formed by reaction of AQ27DSH^– ions and dissolved oxygen.     

Potentiometric measurements of ionic transport parameters in poly(ethylene oxide)-LiX electrolytes

An electrochemical technique based on concentration cell e.m.f. measurements is used to determine the lithium transference number and diffusion coefficient in poly(ethylene oxide)-lithium salt complexes. Measurements were carried out at 90°C on PEO–LiI, PEO–LiClO₄ and PEO–LiCF₃SO₃ electrolytes. According to the phase diagram of the PEO-lithium salt system these complexes are fully amorphous at 90°C. Accurate determination oft _Li ⁺ by the e.m.f. concentration cell method generally requires knowledge of the mean salt activity coefficients. However, this becomes unnecessary when the two electrolyte concentrations differ only slightly. As a first step the mean salt activity coefficient was estimated using a galvanic cell of the lithium/PEO-LiX/MX _n /M type withM ⁿ⁺=Ag⁺ or Pb²⁺, and X^–=I^– or CF₃SO₃ ^–. The resulting lithium transference numbers are 0.34 for the PEO–LiI complex and 0.7 for PEO–LiCF₃SO₃. Discrepancies between thet _Li ⁺ values can be explained by the formation of triplets in the PEO–LiCF₃SO₃ electrolyte. By recording concentration cell potential versus time and comparing with theoretical curves, the salt lithium diffusion coefficient was obtained.D _LiI was found to be around 4×10^–8 cm² s^–1 in PEO–LiI and 8×10^–8 cm² s^–1 in PEO–LiCF₃SO₃ at 90°C. These results suggest a liquid-like behaviour for the microscopic transport mechanism.