Hard–Soft Interactions in Solvent Extraction with Basic Extractants: Comparing Zinc and Cadmium Halides
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ABSTRACT:
SUBMITTER: Lommelen R
PROVIDER: S-EPMC8554786 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A speciation study was carried out for lanthanide complexes formed in the organic phase after solvent extraction with quaternary ammonium and phosphonium nitrate extractants. These extractants are liquid at room temperature and were applied in their undiluted form. A comparison was made between the quaternary compound trihexyl(tetradecyl)phosphonium nitrate, the nitrate form of the commercial extractant Cyphos IL 101, and Aliquat 336 nitrate, the nitrate form of the commercial trialkylmethylammonium chloride extractant Aliquat 336 (alkyl = mixture of C8 and C10 chains). The structures of the lanthanide complexes across the entire lanthanide series (with the exception of promethium) were determined by a combination of solvent extraction techniques, FTIR, NMR, high-resolution steady-state luminescence spectroscopy, luminescence life time measurements, elemental analysis and EXAFS spectroscopy. The results suggest that the lanthanide ions form an anionic nitrate complex in the organic phase by coordinating with five bidentate nitrate ligands. Charge neutralization is provided by two counter cations of the extractant present in the outer coordination sphere of the complex. Furthermore, it is suggested that the pentanitrato complex is the sole lanthanide species that is formed in significant concentrations in the organic phase.
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Project description:The present work describes the reactions of CdI2 with 2-pyridyl aldoxime (2paoH), 3-pyridyl aldoxime (3paoH), 4-pyridyl aldoxime (4paoH), 2-6-diacetylpyridine dioxime (dapdoH2) and 2,6-pyridyl diamidoxime (LH4). The primary goal was to contribute to understanding the molecular basis of the very good liquid extraction ability of 2-pyridyl ketoximes with long aliphatic chains towards toxic Cd(II) and the inability of their 4-pyridyl isomers for this extraction. Our systematic investigation provided access to coordination complexes [CdI2(2paoH)2] (1), {[CdI2(3paoH)2]}n (2), {[CdI2(4paoH)2]}n (3) and [CdI2(dapdoH2)] (4). The reaction of CdI2 and LH4 in EtOH resulted in a Cd(II)-involving reaction of the bis(amidoxime) and isolation of [CdI2(L'H2)] (5), where L'H2 is the new ligand 2,6-bis(ethoxy)pyridine diimine. A mechanism of this transformation has been proposed. The structures of 1, 2, 3, 4·2EtOH and 5 were determined by single-crystal X-ray crystallography. The complexes have been characterized by FT-IR and FT-Raman spectra in the solid state and the data are discussed in terms of structural features. The stability of the complexes in DMSO was investigated by 1H NMR spectroscopy. Our studies confirm that the excellent extraction ability of 2-pyridyl ketoximes is due to the chelating nature of the extractants leading to thermodynamically stable Cd(II) complexes. The monodentate coordination of 4-pyridyl ketoximes (as confirmed in our model complexes with 4paoH and 3paoH) seems to be responsible for their poor performance as extractants.
| S-EPMC8911866 | biostudies-literature
Project description:We report on the separation and recovery of scandium(III) from sulfate solutions using solvent extraction and a membrane transport system utilizing newly synthesized amic acid extractants. Scandium(III) was quantitatively extracted with 50 mmol dm-3 N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]glycine (D2EHAG) or N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]phenylalanine (D2EHAF) in n-dodecane at pH 2 and easily stripped using a 0.5 mol dm-3 sulfuric acid solution. The extraction mechanisms of scandium(III) extraction with D2EHAG and D2EHAF were examined, and it was established that scandium(III) formed a 1:3 complex with both extractants (HR), that is, Sc(SO4)2 - aq + 1.5(HR)2org ⇄ Sc(SO4)R(HR)2org + H+ aq + SO4 2- aq. The equilibrium constants of extraction were evaluated to be 4.87 and 9.99 (mol dm-3)0.5 for D2EHAG and D2EHAF, respectively. D2EHAG and D2EHAF preferentially extracted scandium(III) with a high selectivity compared to common transition metal ions under high acidic conditions (0 < pH ≤ 3). In addition, scandium(III) was quantitatively transported from a feed solution into a 0.5 mol dm-3 sulfuric acid receiving solution through a polymer inclusion membrane (PIM) containing D2EHAF as a carrier. Scandium(III) was completely separated thermodynamically from nickel(II), aluminum(III), cobalt(II), manganese(II), chromium(III), calcium(II), and magnesium(II), and partially separated from iron(III) kinetically using a PIM containing D2EHAF as a carrier. The initial flux value for scandium(III) (J 0,Sc = 1.9 × 10-7 mol m-2 s-1) was two times higher than that of iron(III) (J 0,Fe = 9.3 × 10-8 mol m-2 s-1).
| S-EPMC6921615 | biostudies-literature
Project description:Segmented polyurethane ionomers find prominent applications in the biomedical field since they can combine the good mechanical and biostability properties of polyurethanes (PUs) with the strong hydrophilicity features of ionomers. In this work, PU ionomers were prepared from a carboxylated diol, poly(tetrahydrofuran) (soft phase) and a small library of diisocyanates (hard phase), either aliphatic or aromatic. The synthesized PUs were characterized to investigate the effect of ionic groups and the nature of diisocyanate upon the structure-property relationship. Results showed how the polymer hard/soft phase segregation was affected by both the concentration of ionic groups and the type of diisocyanate. Specifically, PUs obtained with aliphatic diisocyanates possessed a hard/soft phase segregation stronger than PUs with aromatic diisocyanates, as well as greater bulk and surface hydrophilicity. In contrast, a higher content of ionic groups per polymer repeat unit promoted phase mixing. The neutralization of polymer ionic groups with silver or zinc further increased the hard/soft phase segregation and provided polymers with antimicrobial properties. In particular, the Zinc/PU hybrid systems possessed activity only against the Gram-positive Staphylococcus epidermidis while Silver/PU systems were active also against the Gram-negative Pseudomonas aeruginosa. The herein-obtained polyurethanes could find promising applications as antimicrobial coatings for different kinds of surfaces including medical devices, fabric for wound dressings and other textiles.
| S-EPMC8200980 | biostudies-literature
Project description: Not available
| S-EPMC2862972 | biostudies-literature
Project description:Reconstruction of complex craniomaxillofacial (CMF) defects is challenging due to the highly organized layering of multiple tissue types. Such compartmentalization necessitates the precise and effective use of cells and other biologics to recapitulate the native tissue anatomy. In this study, intra-operative bioprinting (IOB) of different CMF tissues, including bone, skin, and composite (hard/soft) tissues, is demonstrated directly on rats in a surgical setting. A novel extrudable osteogenic hard tissue ink is introduced, which induced substantial bone regeneration, with ≈80% bone coverage area of calvarial defects in 6 weeks. Using droplet-based bioprinting, the soft tissue ink accelerated the reconstruction of full-thickness skin defects and facilitated up to 60% wound closure in 6 days. Most importantly, the use of a hybrid IOB approach is unveiled to reconstitute hard/soft composite tissues in a stratified arrangement with controlled spatial bioink deposition conforming the shape of a new composite defect model, which resulted in ≈80% skin wound closure in 10 days and 50% bone coverage area at Week 6. The presented approach will be absolutely unique in the clinical realm of CMF defects and will have a significant impact on translating bioprinting technologies into the clinic in the future.
| S-EPMC8376234 | biostudies-literature
Project description:An auxetic design is proposed by soft-hard material integration and demonstrate negative Poisson's ratio (NPR) can be achieved by leveraging unique rotation features of non-connected hard particles in a soft matrix. A theoretical mechanics framework that describes rotation of hard particles in a soft matrix under a mechanical loading is incorporated with overall Poisson's ratio of the soft-hard integrated metamaterials. The theoretical analysis shows that the auxetic behaviour of the soft-hard integrated structures not only relies critically on geometry of particles, but also depends on their periodic arrangements in the soft matrix. Extensive finite-element analyses (FEA) are performed and validate the theoretical predictions of hard-particle rotation and overall Poisson's ratio of soft-hard integrated structures. Furthermore, uniaxial tensile tests are carried out on three-dimensional printed soft-hard integrated structures and confirm auxetic behaviour of soft-hard integrated structures enabled by the rotation of hard particles. Besides, Poisson's ratio varies nonlinearly with the thickness of specimens and reaches a maximum NPR far out of the bounds of plane stress and plane strain situations, which agrees well with FEA. This work provides a theoretical foundation for the design of mechanical metamaterials enabled by soft-hard material integration with auxetic deformation behaviour.
| S-EPMC6735479 | biostudies-literature
Project description:Two isomeric diglycolamide (DGA) extractants, N,N'-dimethyl-N,N'-dioctyl diglycolamide (LI) and N,N-dimethyl-N',N'-dioctyl diglycolamide (LII), were used to perform a comparative study on the extraction performances towards several lanthanides by extraction experiments and theoretical calculations. The experimental results show that both LI and LII show a positive sequence on the extraction of lanthanides, and LI exhibits the higher complex ability with these lanthanides than LII, except for La and Ce. Slope analysis shows that 1:2 or 1:3 complexes are formed between the two ligands and the metal ions. The geometrical structures of the complexes were optimized in the gas phase by density functional theory (DFT) on the basis of complex compositions. The results of bond lengths, MBOs and topological analysis indicated that the electrostatic interaction between metal ions and two amide O atoms in the LII ligand is not as homogeneous as in LI, and this inhomogeneity is likely to be related to the poor extraction performance of LII.
| S-EPMC8978646 | biostudies-literature
Project description:Biomechanical modelling is a powerful tool for quantifying the evolution of functional performance in extinct animals to understand key anatomical innovations and selective pressures driving major evolutionary radiations. However, the fossil record is composed predominantly of hard parts, forcing palaeontologists to reconstruct soft tissue properties in such models. Rarely are these reconstruction approaches validated on extant animals, despite soft tissue properties being highly determinant of functional performance. The extent to which soft tissue reconstructions and biomechanical models accurately predict quantitative or even qualitative patterns in macroevolutionary studies is therefore unknown. Here, we modelled the masticatory system in extant rodents to objectively test the ability of current muscle reconstruction methods to correctly identify quantitative and qualitative differences between macroevolutionary morphotypes. Baseline models generated using measured soft tissue properties yielded differences in muscle proportions, bite force, and bone stress expected between extant sciuromorph, myomorph, and hystricomorph rodents. However, predictions from models generated using reconstruction methods typically used in fossil studies varied widely from high levels of quantitative accuracy to a failure to correctly capture even relative differences between macroevolutionary morphotypes. Our novel experiment emphasizes that correctly reconstructing even qualitative differences between taxa in a macroevolutionary radiation is challenging using current methods. Future studies of fossil taxa should incorporate systematic assessments of reconstruction error into their hypothesis testing and, moreover, seek to expand primary datasets on muscle properties in extant taxa to better inform soft tissue reconstructions in macroevolutionary studies.
| S-EPMC7935025 | biostudies-literature
Project description:Pollen's practically-indestructible shell structure has long inspired the biomimetic design of organic materials. However, there is limited understanding of how the mechanical, chemical, and adhesion properties of pollen are biologically controlled and whether strategies can be devised to manipulate pollen beyond natural performance limits. Here, we report a facile approach to transform pollen grains into soft microgel by remodeling pollen shells. Marked alterations to the pollen substructures led to environmental stimuli responsiveness, which reveal how the interplay of substructure-specific material properties dictates microgel swelling behavior. Our investigation of pollen grains from across the plant kingdom further showed that microgel formation occurs with tested pollen species from eudicot plants. Collectively, our experimental and computational results offer fundamental insights into how tuning pollen structure can cause dramatic alterations to material properties, and inspire future investigation into understanding how the material science of pollen might influence plant reproductive success.
| S-EPMC7081183 | biostudies-literature