Exploring the complexation behaviour of NpO with diglycolamide in ionic liquid aqueous solution.

The complexation of NpO with tetramethyl diglycolamide (TMDGA) was investigated in an ionic liquid (IL: 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, Bumim.TfN), with the objective of understanding its complexation behaviour and optical properties in both IL and aqueous media. We successfully prepared the NpO(TfN) salt, and its complexation with TMDGA was studied using absorption spectroscopy.

Radiation stability of two extraction chromatography resins containing aza-crown-based diglycolamides used for Am(III) uptake.

The radiolytic stability of two extraction chromatography resins with multiple diglycolamide arms was investigated by exposing them to gamma radiation and carrying out uptake studies of Am(III) from acidic feeds. The resins contained aza-crown-based diglycolamide (DGA) ligands, viz., triaza-9-crown-3-N,N',N"-trisdiglycolamide (TAM-3-DGA) and tetraaza-12-crown-4-N,N',N",N'"-tetrakisdiglycolamide (TAM-4-DGA), where the DGA moieties were grafted to the 'N' atoms of the macrocyclic ring.

Complexation of Actinyl Ions with DHOA and TBP in an Ionic Liquid and a Molecular Solvent: How Similar or Different Are They?

Complexation thermodynamics of uranyl ions with well-known reprocessing ligands like tributyl phosphate (TBP) and dihexyl octanamide (DHOA) was studied in an ionic liquid (IL) versus a molecular solvent. Whereas 1-butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (Bumim·TfN) was used as an IL due to its favorable viscosity, acetonitrile was the choice of molecular solvent due to its poor coordinating nature. Optical spectroscopy studies revealed that UO ions formed species of the types ML and ML with both TBP and DHOA, in a stepwise manner.

Understanding the Complexation of Alkyl-Substituted Nitrilotriacetamides with Uranium: A Study by Absorption Spectroscopy and Microcalorimetry.

Complexation thermodynamics of UO ions with a series of alkyl-substituted nitrilotriacetamides (NTA) was investigated by absorption spectroscopy and microcalorimetry. The hexamethyl derivative of NTA (HMNTA) forms the weakest two successive complexes with UO ions with stability constants of log β = 3.5 ± 0.

Understanding the Interaction of Uranyl Cation with Two -Pivot Tripodal Amides: Synthesis, Complexation, Microcalorimetry, and DFT Studies.

Complexation of uranyl ions with two structurally related -pivotal tripodal amides with varying spacer lengths, synthesized for the first time, was studied by optical spectroscopy. In the tripodal amides, the coordination was through the carbonyl atoms where the carbonyl groups were away from the central atom by three spacer atoms () and four spacer atoms (), respectively. Increasing the spacer atoms going from to favors the complexation with the linear uranyl cations and results in stronger complex formation.

Efficient actinide sequestration with ionic liquid-based extraction chromatography resins containing Aza-crown ether functionalized diglycolamides.

Two new extraction chromatographic resins (ECRs) were prepared by impregnating two exotic diglycolamide (DGA) ligands (having three or four DGA moieties tethered to aza-crown ether scaffolds) dissolved in an ionic liquid onto an inert solid support. A room temperature ionic liquid (RTIL) was used for enhancing the performance of the ECRs. The ECR containing triaza-9-crown-3 functionalized with three DGA moieties (TAM-3-DGA), and tetraaza-12-crown-4 tethered with four DGA arms (TAM-4-DGA) were evaluated for the separation of Am and Pufrom nitric acid solutions.

Stability of composite polymeric beads containing a calix[4]arene-mono-crown-6 ligand for radio-cesium separation.

Bis-octyloxy-calix[4]arene-mono-crown-6 (BOCMC) is a selective ligand for Cs(I) cation, and has been used in solvent extraction method for its separation from acidic feed. Looking at the various advantages and ease of extraction chromatography separation method, an attempt was made to prepare stable composite beads containing BOCMC entrapped in a suitable polymeric matrix. Therefore, an attempt was made to prepare a series of composite polymeric beads containing BOCMC in polysulfone (PS), polyether sulfone (PES) and sodium alginate polymeric matrix.

Metal-organic frameworks as superior porous adsorbents for radionuclide sequestration: Current status and perspectives.

Efficient separation of hazardous radionuclides from radioactive waste remains a challenge to the global acceptance of nuclear power due to complex nature of the waste, high radiotoxicities and presence of large number of interfering elements. Sorption of radioactive elements from liquid phase, gas phase or their solid particulates on various synthetic organic, inorganic or biological sorbents is looked as one of the options for their remediation. In this context, highly porous materials, termed as metal-organic frameworks (MOFs), have shown promise for efficient capturing of various types of radioactive elements.

Highly efficient plutonium scavenging by an extraction chromatography resin containing a tetraaza-12-crown-4 ligand tethered with four diglycolamide pendent arms.

An efficient extraction chromatography resin, containing tetraaza-12-crown-4 functionalized with four diglycolamide moieties, was evaluated for the separation of plutonium. This chromatography resin yielded very large distribution coefficients for Pu (>10) in 0.5 - 6 M HNO feed solutions.

Actinide ion uptake from acidic radioactive feeds using an extraction chromatographic resin containing a branched dialkyl amide.

A dialkyl amide with branched alkyl group, viz. N,N-di(2-ethylhexyl)-propionamide (D2EHPrA) was used as the organic extractant in an extraction chromatographic resin prepared for the first time and evaluated for the separation of uranium from acidic feeds. The distribution coefficient measurements, carried out at varying HNO concentrations, indicated an increase in the UO ion sorption with increasing nitric acid concentration.

Highly efficient actinide(III)/lanthanide(III) separation by novel pillar[5]arene-based picolinamide ligands: A study on synthesis, solvent extraction and complexation.

Selective extraction of highly radiotoxic actinides(III) is an important and challenging task in nuclear wastewater treatment. Many proposed ligands containing S or P atoms have drawbacks including high reagent consumption and possible secondary pollution after incineration. The present work reports five novel pillar[5]arene-based extractants that are anchored with picolinamide substituents of different electronic nature by varying spacer.

Unfolding the complexation and extraction of Am and Eu using N-heterocyclic aromatic diphosphonic acids: a combined experimental and DFT study.

Phosphonate based ligands are well known for the extraction of 'f' block elements. Three N,O-donor N-heterocyclic aromatic diphosphonate ligands were evaluated in the present work for the extraction/separation studies of Am and Eu. Complexation studies in aqueous medium using luminescence titration indicated the formation of anionic complexes in the case of Eu.

Evaluation of two aza-crown ether-based multiple diglycolamide-containing ligands for complexation with the tetravalent actinide ions Np and Pu: extraction and DFT studies.

Two multiple diglycolamide (DGA)-containing extractants where the DGA arms are tethered to the nitrogen atoms of two aza-crown ether scaffolds, a 9-membered aza-crown ether containing three 'N' atoms (L) and a 12-membered aza-crown ether containing four 'N' atoms (L), were evaluated for the extraction of the tetravalent actinide ions Np and Pu. The tripodal ligand with three DGA arms (L) was relatively inferior in its metal ion extraction properties as compared to the tetrapodal ligand with four DGA arms (L) and Pu ion was better extracted than Np ion with both the ligands. A solvation extraction mechanism, where species of the type ML(NO) are extracted, was found to be operative for both the ligands involving both the tetravalent actinide ions.

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies.

A series of four N-pivot tripodal diglycolamide (DGA) ligands, where three DGA moieties are attached to the central N atom via spacers of different lengths and with varying alkyl substituents on the amidic nitrogen of DGA (L-L), were studied for their extraction and complexation ability toward trivalent lanthanide/actinide ions, including solvent extraction, complexation using spectrophotometric titrations, and luminescence spectroscopic studies. Introduction of a methyl group on the amidic nitrogen atom gives rise to a 400 fold increase of the Eu distribution ( D) value [L (NMe) vs L (NH)] at 1 M HNO. Enlargement of the spacer length between the pivotal N atom and the DGA moieties with one carbon atom results in a 14 times higher D value [L (C3) vs L (C2)].

Effect of an alkyl substituent and spacer length in benzene-centered tripodal diglycolamides on the sequestration of minor actinides.

Three benzene-centered tripodal diglycolamide (Bz-T-DGA) ligands, where diglycolamide (DGA) moieties are tethered to the central benzene ring through a methylene spacer and having either a hydrogen atom (LI) or an isopentyl group (LII) attached to the N-atom, and DGA moieties attached via an ethylene spacer and having an isopentyl group attached to the N-atom (LIII), were studied for their complexation and extraction abilities towards trivalent actinides and lanthanides. The distribution ratio of Am(iii) and Eu(iii) with 1 mmol L-1 ligand in 5% iso-decanol/n-dodecane followed the order: LII > LIII > LI. The substitution of the H atom with the isopentyl group on the N-atom of the DGA moieties resulted in two orders of magnitude enhancement in the extraction ability of the ligand.

Liquid-liquid extraction and facilitated transport of f-elements using an N-pivot tripodal ligand.

Diglycolamide (DGA)-functionalized tripodal ligands offer the required nine-coordinated complex for effective binding to a trivalent lanthanide/actinide ion. A N-pivot tripodal ligand (TREN-DGA) containing three DGA pendant arms was evaluated for the extraction and supported liquid membrane transport studies using PTFE flat sheets. Solvent extraction studies indicated preferential extraction of 1:1 (M:L) species, while the metal ion extraction increased with increasing HNO concentration conforming to a solvated species extraction.

Unusual extraction of trivalent f-cations using diglycolamide dendrimers in a room temperature ionic liquid: extraction, spectroscopic and DFT studies.

The complexation of Am and Eu was studied with three generations of diglycolamide (DGA)-functionalized poly(propylene imine) diaminobutane dendrimers (DGA-Den) with two, four and eight DGA moieties by solvent extraction and luminescence spectroscopy in a room temperature ionic liquid, viz. 3-butyl-1-methyl imidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TfN]). The extraction of trivalent f-cations was found to increase with decreasing HNO concentrations conforming to a cation exchange mechanism with the extraction of Eu being higher than that of Am in the acid concentration range of 0.

Benzene-centred tripodal diglycolamides for the sequestration of trivalent actinides: metal ion extraction and luminescence spectroscopic investigations in a room temperature ionic liquid.

Three benzene-centred tripodal diglycolamide (Bz-T-DGA) ligands, where the diglycolamide (DGA) moieties are attached to a central benzene ring through ethylene spacers (LI), amide groups (LII) or ether linkages (LIII), were evaluated for their extraction behaviour towards trivalent actinide and lanthanide ions in a room temperature ionic liquid (RTIL), viz. 1-butyl-3-methylimidazolium bis(trifluoromethane)sulfonimide ([Cmim][TfN]). The extraction behaviour of these ligands in [Cmim][TfN] medium was compared with that obtained in the molecular solvent n-dodecane showing an opposite selectivity of LIII > LII > LIvs.

Complexation of tetraalkyl diglycolamides with trivalent f-cations in a room temperature ionic liquid: extraction and spectroscopic investigations.

This paper reports the complexation of a series of tetraalkyl diglycolamides (TRDGA) with trivalent f-cations in a room temperature ionic liquid, viz., 3-octyl-1-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TfN]). The stability constants of TRDGA/Nd complexes (where R = n-pentyl, n-hexyl, n-octyl, n-decyl and 2-ethylhexl) were determined by absorbance spectroscopy.

A review on solid phase extraction of actinides and lanthanides with amide based extractants.

Solid phase extraction is gaining attention from separation scientists due to its high chromatographic utility. Though both grafted and impregnated forms of solid phase extraction resins are popular, the later is easy to make by impregnating a given organic extractant on to an inert solid support. Solid phase extraction on an impregnated support, also known as extraction chromatography, combines the advantages of liquid-liquid extraction and the ion exchange chromatography methods.

Benzene-centered tripodal diglycolamides: synthesis, metal ion extraction, luminescence spectroscopy, and DFT studies.

Three benzene-centered tripodal diglycolamides (Bz-T-DGAs) were synthesized and evaluated for actinide, lanthanide, and fission product ion extraction. 1,3,5-Triethylbenzene-based tripodal DGA (LI) showed high distribution ratio (D) values for Am and Eu in a mixture of 95% n-dodecane and 5% iso-decanol at 3 M HNO. Eu/Am separation factors, in the range of 8-10, were obtained at 1 M HNO which decreased at higher acidities with the exception of LII which did not show much change.

Cauliflower Leave, an Agricultural Waste Biomass Adsorbent, and Its Application for the Removal of MB Dye from Aqueous Solution: Equilibrium, Kinetics, and Thermodynamic Studies.

Cauliflower leaf powder (CLP), a biosorbent prepared from seasonal agricultural crop waste material, has been employed as a prospective adsorbent for the removal of a basic dye, methylene blue (MB) from aqueous solution by the batch adsorption method under varying conditions, namely, initial dye concentration, adsorbent dose, solution pH, and temperature. Characterization of the material by FTIR and SEM indicates the presence of functional groups and rough coarse surface suitable for the adsorption of methylene blue over it. Efforts were made to fit the isotherm data using Langmuir, Freundlich, and Temkin equation.

Diglycolamide-functionalized poly(propylene imine) diaminobutane dendrimers for sequestration of trivalent f-elements: synthesis, extraction and complexation.

Three diglycolamide-functionalized poly(propylene imine) diaminobutane dendrimers, viz., zero generation (LI), first generation (LII), and second generation (LIII), were synthesized and evaluated for their complexation ability towards trivalent actinides and lanthanides. The distribution coefficient (D) of Am with 1.

Thermodynamics of biphasic lanthanide extraction by tripodal diglycolamide: a solution calorimetry study.

Isothermal titration calorimetry was employed for the direct measurement of the enthalpy of extraction (ΔH) of Eu(NO) by using a tripodal diglycolamide (T-DGA) ligand dissolved in n-dodecane containing 5% (v/v) 2-decanol. The enthalpy of extraction obtained by titration calorimetry was in good agreement with the enthalpy of extraction calculated from the temperature dependence of the distribution coefficients by using the van't Hoff equation. The Gibbs free energy and the entropy of extraction (ΔG and ΔS) for the extraction of Eu(NO) by T-DGA were also obtained by solvent extraction experiments.

Understanding the complexation of Eu(3+) with three diglycolamide-functionalized calix[4]arenes: spectroscopic and DFT studies.

Complexation of Eu(3+) with three diglycolamide-functionalized calix[4]arene (C4DGA) ligands was investigated by UV-Vis and luminescence spectroscopy measurements in acetonitrile medium. The complexation thermodynamics was studied by micro-calorimetry while structural information was obtained from DFT calculations.