Simultaneous production of89Zr and90,91m92mNb in α-particle activated yttrium and their subsequent separation by TOA

A study on the separation of lithium isotopes was carried out with an ion exchange resin having 1,7,13-trioxa-4,10,16-triazacyclooctadecane (N₃O₃) as an anchor group. The lighter isotope,⁶Li concentrated in the resin phase, while the heavier isotope,⁷Li is enriched in the fluid phase. Upon column chromatography [0.6 cm (I. D.)×20 cm (height)] using 1.0M ammonium chloride solution as an eluent, single separation factor, , 1.068 (⁶Li/⁷Li)_resin/(⁶Li/⁷Li)_solution was obtained by theGlueckauf method from the elution curve and isotope ratios.     

Syntheses and separating properties of triazacrown and AM18C6 bonded Merrifield peptide resins

Separation of lithium and magnesium isotopes by cation exchange elution chromatography was carried out with a synthesized 1,13,16-trioxa-4,7,10-triazacyclooctadecane (N₃O₃)-4,7,10-trimerrifield peptide resin and with a 2^′-aminomethyl-18-crown-6 (AM18C6) bonded Merrifield peptide resin. The resins have a capacity of 0.1 and 2.3 meq/g dry resin. A single stage separation factor of lithium isotopes, 1.018 was obtained by the Glueckauf theory from the elution curve and isotopic assays. The heavier isotope, ⁷Li was concentrated in the resin phase, while the lighter isotope, ⁶Li concentrated in the solution phase. On the other hand, the heavier isotopes of magnesium were concentrated in the solution phase, while the lighter isotopes were concentrated in the resin phase. The separation factors of ²⁴Mg-²⁵Mg, ²⁴Mg-²⁶Mg, and ²⁵Mg-²⁶Mg isotope pair fractionations were 1.012, 1.022, and 1.012, respectively.     

Separation of lithium isotopes by N4S2 azacrown ion exchanger

The novel N₄S₂ azacrown ion exchange resin was prepared. The ion exchange capacity of N₄S₂ ion exchanger was 0.34 meq/g dry resin. A study on the separation of lithium isotopes was carried out with N₄S₂ azacrown ion exchange resin. The lighter isotope,⁶Li is concentrated in the resin phase, while the heavier isotope,⁷Li is enriched in the solution phase. With column chromatography [0.1 cm (I.D.)×32 cm (height)] using 2.0M NH₄Cl as an eluent, separation factor, a=1.034 was obtained.     

Separation of lithium isotope by azacrown tetramerrifield peptide resin

A study on the separation of lithium isotope was carried out with N₄O azacrown ion exchange resin. The lighter⁶Li isotope concentrated in the solution phase, while the heavier⁷Li isotope is enriched in the resin phase. Upon column chromatography (0.3 cm I.D.×15.5cm height) using 0.5M NH₄Cl as an eluent, single separation factor, α=1.00127 was obtained.     

Separation of lithium isotopes by NTOE-bonded Merrifield peptide resin

A study of the elution chromatographic separation of lithium isotopes was carried out with NTOE-bonded Merrifield peptide resin. This resin had a capacity of 0.29 meq/g dry resin. Upon column chromatography [0.2 cm(I.D)×32 cm (height)] using 1.0M NH₄Cl solution as an eluent, a single separation factor of 1.026 was obtained by the Glueckauf theory. The heavier isotope, ⁷Li was concentrated in the resin phase, while the lighter isotope, ⁶Li was enriched in the solution phase.     

Enrichment of lithium isotopes by a triazacrown trimerrifield peptide resin

A study on the elution chromatographic separation of lithium isotopes was carried out with a triazacrown trimerrifield peptide resin. The capacity of the triazacrown trimerrifield peptide resin has a value of 0.08 meq/g. Upon column chromatography [0.2 cm (I.D)×35 cm (height)] using 4.0M NH₄Cl solution as an eluent, the single stage separation factor of 1.028 was obtained by the Glueckauf theory. The heavier isotope, ⁷Li, was concentrated in the resin phase, while the lighter isotope, ⁶Li, was enriched in the solution phase.     

Enrichment of Magnesium Isotopes by N3O2 Azacrown Ion Exchange Resin

The elution chromatographic separation of magnesium isotopes was investigated by chemical ion exchange with the synthesized 1,7-dioxa-4,10,13-triazacyclopentadecane-4,10,13-trimerrifield peptide resin [N₃O₂·3M]. The capacity of novel N₃O₂ azacrown ion exchanger was 0.21 meq/g dry resin. The heavier isotopes of magnesium concentrated in the resin phase, while the lighter isotopes are enriched in the solution phase. The glass ion exchange column used in our experiment was 30 cm long with inner diameter of 0.2 cm, and the 2.0M NH₄Cl solution was used as an eluent. The separation factors of ²⁴Mg-²⁵Mg, ²⁵Mg-²⁶Mg, and ²⁴Mg-²⁶Mg were 1.030, 1.009, and 1.027, respectively.     

Separation of lithium isotopes by N4O2 azacrown ion exchanger

A study on the separation of lithium isotope was carried out with a 1,16-dioxa-4,7,10,13- tetraazacyclooctadecane-4,7,10,13-tetramerrifield peptide resin [N₄O₂·4M]. The resin having N₄O₂ as an anchor group has a capacity of 3.8 meq/g. Upon column chromatography [0.15 cm (I.D)×29 cm (height)] using 0.01 M NH₄Cl as an eluent, the single separation factor, α=1.038 was obtained by the Glueckauf theory from the elution curve and isotope ratios.     

Separation of lithium isotopes by NDOE bonded Merrifield peptide resin

The novel NDOE (1,12,15-triaza-3,4:9,10-dibenzo-5,8-dioxacycloheptadecane) ion exchange resin was prepared. The ion exchange capacity of NDOE azacrown ion exchanger was 0.2 meq/g dry resin. A study on the separation of lithium isotopes was carried out with NDOE novel azacrown ion exchange resin. The lighter isotope,⁶Li concentrated in the solution phase, while the heavier isotope,⁷Li is enriched in the resin phase. By column chromatography (0.1 cm I.D.×32 cm height) using 2.0M NH₄Cl as an eluent, a separation factor,a=1.0201 was obtained.     

The Influence of Electric Parameters on the Dynamics of the Electrokinetic Decontamination of Soils

Elution chromatographic separation of lithium isotopes was carried out with aminobenzo-15-crown-5 bonded merrifield resin. This resin have a capacity of 0.24 meq/g dry resin. By column chromatography using 1.0M NH₄Cl solution as an eluent, a single separation factor 1.026 was obtained from the elution curve and isotope ratios according to the Glucckauf theory. The heavier isotope, ⁷Li was concentrated in the resin phase, while the lighter isotope, ⁶Li enriched in the solution phase.     

Separation of magnesium isotopes by N4S2 azacrown ion exchanger

The chromatographic separation of magnesium isotopes was investigated by chemical ion exchange with 1,16-dithia-4,7,10,13-tetraazacyclooctadecane-4,7,10,13-tetramerrifield peptide resin[N₄S₂·4M] synthesized recently. The capacity of novel N₄S₂ azacrown ion exchanger was 0.34 meq/g dry resin. The heavier isotopes of magnesium concentrated in the resin phase, while the lighter isotopes are enriched in the solution phase. The glass ion exchange column used was 30 cm long with inner diameter of 0.2 cm, and the 1.0M NH₄Cl solution was used as an eluent. The separation factors of²⁴Mg−²⁵Mg,²⁵Mg−²⁶Mg, and²⁴Mg−²⁶Mg were 1.047, 1007, and 1.008, respectively.     

Lithium isotope separation on a monobenzo-15-crown-5 resin

A study on the separation of Li isotopes was carried out with a resin having monobenzo-15-crown-5 as a functional group, synthesized by substitution reaction of chloromethylated styrene-DVB copolymer with 4-aminobenzo-15-crown-5. Adsorption properties of the resin for Li⁺ were invesgated with batch method in various solvents and counter anions. Upon column chromatography [0.9 cm (I. D.)×25 cm (height)] using 5% (v/v) H₂O in acetonitrile as an eluent, single separation factor, , 1.053 (±0.005), (⁶Li/⁷Li)resin/ (⁶Li/⁷Li) solution was obtained by the GLUECKAUF method from the elution curve and isotope ratios.     

Influence of co-ions in the eluent on the separation factor of lithium isotopes

The influence of co-ions in the eluent on the separation factor () of lithium isotope separation has been studied by ion exchange chromatography. A strongly acid cation exchange resin (Dowex 50W-X8) was used for the separation of lithium isotopes. The co-ions used in eluent were H⁺, K⁺, Ba²⁺, Cu²⁺, Al³⁺ and Cr³⁺ as their chlorides. From the experiments, it was found that⁶Li was enriched in the resin phase and⁷Li in solution phase. At the same distribution coefficient (K_d=30), the separation factor increased linearly with the charge of co-ion (=1.0022 to 1.0039).     

Separation of lithium isotopes by elution chromatography with an AB18C6 bonded Merrifield peptide resin

Cation exchange chromatographic separation of lithium isotopes was carried out with an 4'-aminobenzo-18-crown-6(AB18C6) bonded Merrifield peptide resin. This resin has a capacity of 2.25 meq/g dry resin. Upon column elution chromatography, a single stage separation factor of 1.0095, was obtained by the Glueckauf theory from the elution curve and isotopic assays. The heavier isotope, ⁷Li, was concentrated in the resin phase, while the lighter one, ⁶Li, concentrated in the solution phase.     

Green and efficient extraction strategy to lithium isotope separation with double ionic liquids as the medium and ionic associated agent

The paper reported a green and efficient extraction strategy to lithium isotope separation. A 4-methyl-10-hydroxybenzoquinoline (ROH), hydrophobic ionic liquid—1,3-di(isooctyl)imidazolium hexafluorophosphate ([D(i-C₈)IM][PF₆]), and hydrophilic ionic liquid—1-butyl-3-methylimidazolium chloride (ILCl) were used as the chelating agent, extraction medium and ionic associated agent. Lithium ion (Li⁺) first reacted with ROH in strong alkali solution to produce a lithium complex anion. It then associated with IL⁺ to form the Li(RO)₂IL complex, which was rapidly extracted into the organic phase. Factors for effect on the lithium isotope separation were examined. To obtain high extraction efficiency, a saturated ROH in the [D(i-C₈)IM][PF₆] (0.3 mol l^?1), mixed aqueous solution containing 0.3 mol l^?1 lithium chloride, 1.6 mol l^?1 sodium hydroxide and 0.8 mol l^?1 ILCl and 3:1 were selected as the organic phase, aqueous phase and phase ratio (o/a). Under optimized conditions, the single-stage extraction efficiency was found to be 52 %. The saturated lithium concentration in the organic phase was up to 0.15 mol l^?1. The free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) of the extraction process were ?0.097 J mol^?1, ?14.70 J mol K^?1 and ?48.17 J mol^?1 K^?1, indicating a exothermic process. The partition coefficients of lithium will enhance with decrease of the temperature. Thus, a 25 °C of operating temperature was employed for total lithium isotope separation process. Lithium in Li(RO)₂IL was stripped by the sodium chloride of 5 mol l^?1 with a phase ratio (o/a) of 4. The lithium isotope exchange reaction in the interface between organic phase and aqueous phase reached the equilibrium within 1 min. The single-stage isotope separation factor of ⁷Li–⁶Li was up to 1.023 ± 0.002, indicating that ⁷Li was concentrated in organic phase and ⁶Li was concentrated in aqueous phase. All chemical reagents used can be well recycled. The extraction strategy offers green nature, low product cost, high efficiency and good application prospect to lithium isotope separation.     

Calciumisotopenseparation und Reaktionsenthalpie. Calciumisotopenseparation und Bestimmung der Reaktionsenthalpie beim Isotopenaustausch an einem stark sauren Kationenaustauscher

Calcium Isotope Separation and Reaction Enthalpy. Calcium Isotope Separation and Determination of Reaction Enthalpy in Ion Exchange Using a Strongly Acidic Cation Exchange Resin In the system of a strongly acidic cation exchanger/BaCl₂ solution the isotope separation between ⁴⁰Ca²⁺ and ⁴⁸Ca²⁺ is investigated using column experiments. ⁴⁸Ca²⁺ is enriched in the solution phase whereas ⁴⁰Ca²⁺ is enriched in the resin phase. A strong dependence of the isotope separation effect on the concentration of the BaCl₂ solution is found. The isotope separation increases with decreasing concentration. The isotope separation also depends on temperature: the isotope separation effect increases with decreasing temperature. A ΔH-value of —5.8 J/mol is determined for the calcium isotope exchange reaction.     

Separation of magnesium isotopes by chemical exchange with a polymer-bound azacrown compound

The chromatographic separation of magnesium isotopes was investigated by chemical exchange with the recently synthesized 1-oxa-4,7,10,13-tetraazacyclopentadecane-4,7,10,13-tetramerrifield peptide resin [N₄O·4M]. The capacity of the novel N₄O-4 Merrifield ion exchanger was 1.0 meq/g dry resin. The heavier isotope²⁶Mg concentrated in the resin phase, while the lighter isotopes²⁴Mg, and²⁵Mg are enriched in the fluid phase. The maximum separation factors , for²⁵Mg–²⁶Mg and²⁴Mg–²⁶Mg were found to be 1.048 and 1.022, respectively, at 20.0±0.02 °C with 2.0 M ammonium chloride solution as an eluent.     

Separation of magnesium isotopes by NTOE bonded merrifield peptide resin

Separation of magnesium isotopes was investigated by chemical ion exchange with synthesyzed 1,12-diaza-3,4:9,10-dibenzo-5,8-dioxacyclo pentadecane(NTOE) bonded merrifield peptide resin using elution chromatographic technique. The capacity of novel diazacrown ion exchanger was 0.29 meq/g dry resin. The heavier isotopes of magnesium were concentrated in the solution phase, while the lighter isotopes were enriched in the resin phase. The glass ion exchange column used in our experiment was 32 cm long with inner diameter of 0.2 cm, and 0.5M NH₄Cl solution was used as an eluent. The single stage separation factor was determined according to the method of GLUECKAUF from the elution curve and isotopic assays. The separation factors of ²⁴Mg²⁺–²⁵Mg²⁺, ²⁴Mg²⁺–²⁶Mg²⁺, and ²⁵Mg²⁺–₂₆Mg²⁺ were 1.063, 1.080, and 1.021, respectively.     

Origin of the irreversible plateau (4.5 V) of Li[Li0.182Ni0.182Co0.091Mn0.545]O2 layered material

Layered LiNi_0.4Co_0.2Mn_0.4O₂, Li[Li_0.182Ni_0.182Co_0.091Mn_0.545]O₂, Li[Li_1/3Mn_2/3]O₂ powder materials were prepared by rheological phase method. XRD characterization shows that these samples all have analogous structure to LiCoO₂. Li[Li_0.182Ni_0.182Co_0.091Mn_0.545]O₂ can be considered to be the solid solution of LiNi_0.4Co_0.2Mn_0.4O₂ and Li[Li_1/3Mn_2/3]O₂. Detailed information from XRD, ex situ XPS measurement and electrochemical analysis of these three materials reveals the origin of the irreversible plateau (4.5 V) of Li[Li_0.182Ni_0.182Co_0.091Mn_0.545]O₂ electrode. The irreversible oxidation reaction occurred in the first charging above 4.5 V is ascribed to the contribution of Li[Li_1/3Mn_2/3]O₂ component, which maybe extract Li⁺ from the transition layer in Li[Li_1/3Mn_2/3]O₂ or Li[Li_0.182Ni_0.182Co_0.091Mn_0.545]O₂ through oxygen release. This step also activates Mn⁴⁺ of Li[Li_1/3Mn_2/3]O₂ or Li[Li_0.182Ni_0.182Co_0.091Mn_0.545]O₂, it can be reversibly reduced/oxidized between Mn⁴⁺ and Mn³⁺ in the subsequent cycles.     

Siloxyaluminate and Siloxygallate Complexes as Models for Framework and Partially Hydrolyzed Framework Sites in Zeolites and Zeotypes

Anionic molecular models for nonhydrolyzed and partially hydrolyzed aluminum and gallium framework sites on silica, M[OSi(OtBu)₃]₄⁻ and HOM[OSi(OtBu)₃]₃⁻ (where M=Al or Ga), were synthesized from anionic chlorides Li{M[OSi(OtBu)₃]₃Cl} in salt metathesis reactions. Sequestration of lithium cations with [12]crown-4 afforded charge-separated ion pairs composed of monomeric anions M[OSi(OtBu)₃]₄⁻ with outer-sphere [([12]crown-4)₂Li]⁺ cations, and hydroxides {HOM[OSi(OtBu)₃]₃} with pendant [([12]crown-4)Li]⁺ cations. These molecular models were characterized by single-crystal X-ray diffraction, vibrational spectroscopy, mass spectrometry and NMR spectroscopy. Upon treatment of monomeric [([12]crown-4)Li]{HOM[OSi(OtBu)₃]₃} complexes with benzyl alcohol, benzyloxide complexes were formed, modeling a possible pathway for the formation of active sites for Meerwin–Ponndorf–Verley (MPV) transfer hydrogenations with Al/Ga-doped silica catalysts.