Solid state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3)

A time resolved, in-situ X-ray diffraction study of the de-intercalation of anions and lithium cations from [LiAl2(OH)(6)](n)X center dot qH(2)O (X = Cl-, Br-, NO3-, SO42-)

The layered double hydroxides (LDHs), [LiAl2(OH) 6]nX·qH2O (Xn- = CP -, Br-, NO3,- SO42-) spontaneously lose both Li+ cations and Xn- anions to give crystalline Al(OH)3 on stirring in water. The kinetics of this topochemical de-intercalation reaction have been studied using time-resolved, in-situ energy dispersive X-ray powder diffraction. The temperature dependence of the rate of the de-intercalation reaction yields activation energies of 94 ± 15 kJ mol-1 for mono-dispersed [LiAl2(OH)6]Cl·1.5H2O crystallites (particle size 5-10 μm) and 117 ± 15 kJ mol-1 for poly-dispersed [LiAl2(OH)6]Cl·1.5H2O crystallites (particle size 1-30 μm). The rate of ion de-intercalation was found to decrease as the H2O/LDH ratio decreased. The rate of the de-intercalation has also been shown to be dependent on the interlayer anion, with the reaction rates NO3- > Cl- > Br-. In the case of SO42- rapid de-intercalation only goes to 40% completion

Effect of morphology and particle size on the ionic conductivities of composite solid electrolytes

A model incorporating the surface conductivity and morphology of the composite solid electrolytes is envisaged to explain their conduction behaviour. The conductivity data on LinX−50 m/o Al2O3 (X = F−, Cl−, Br−, CO32−, SO42−, PO43−) composites prepared by thermal decomposition of LinX·2nAl(OH)3·mH2O salts and Li2SO4−A (A=Al2O3, CeO2, Y2O3, Yb2O3, Zr2O3, ZrO2 and BaTiO3) composites prepared by mechanical mixing of the components are examined in the light of this model. It is surmised that the particle size of both the dispersoids and the hosts not only influence the ionic conductivity of the host matrix but also affect its bulk properties

Magnetic nanoparticles stabilized in layered double hydroxides

The morphological and magnetic properties of nickel nanoparticles have been investigated. The particles were prepared by thermal decomposition in vacuum of a nickel complex [Ni(edta)]2 intercalated into Li/Al layered double hydroxide (LDH). It has been shown that this complex without templating within an LDH matrix gives rise to Ni3C particles of much larger sizes. Magnetic measurements were used to detect superparamagnetic behaviour of the nickel phase

Precision studies of QCD in the low energy domain of the EIC

This White Paper aims at highlighting the important benefits in the science reach of the EIC. High luminosity operation is generally desirable, as it enables producing and harvesting scientific results in a shorter time period. It becomes crucial for programs that would require many months or even years of operation at lower luminosity