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Malonamide derivatives, which are the most extensively investigated extractants for solvent extraction of lanthanides, actinides, and platinum group metal ions, were deuterated by using Pd/C and Rh/C catalysts in a D2O/2-propanol mixture. This method replaces 1H atoms in the malonamides with 2H atoms at a controllable deuteration rate. The maximum rate reached about 75%, determined by nuclear magnetic resonance and electrospray ionization – mass spectrometry. The extraction behavior of metal ions by the malonamides was unchanged by the deuteration. Deuterated malonamides are a powerful tool for fundamental research on solvent extraction systems and for structural analysis of organic phases. The large difference in the cross section of coherent neutron scattering between 1H and 2H leads to a large difference in neutron scattering length density of malonamide derivatives before and after the deuteration. Therefore, using deuterated malonamides in small-angle neutron scattering and neutron reflectivity studies may help to reveal the microscopic structure of the specific solute species in the bulk organic phase and at the liquid–liquid interface, respectively. In this paper, we report the advantage of the deuterated malonamides for a contrast-matching method in the SANS experiment. This deuteration method could be generalized and extended to a wide variety of extractant molecules.

This study investigates the formation of amorphous tetravalent metal hydroxides, M(OH)

There is an ever-increasing body of evidence that metallic complexes involving amphiliphic ligands do not form normal solutions in organic solvents. Instead, they form complex fluids with intricate structures. For example, the metallic complexes may aggregate into clusters, and these clusters themselves may aggregate into superclusters. To gain a deeper insight into the mechanisms at play, we have used an improved force field to conduct extensive molecular dynamics simulations of a system composed of zirconium nitrate, water, nitric acid, tri-n-butyl phosphate, and n-octane. The important new finding is that a dynamic equilibrium between the cis and trans isomers of the metal complex is likely to play a key role in the aggregation behavior. The isolated cis and trans isomers have similar energies, but simulation indicates that the clusters consist predominantly of cis isomers. With increasing metal concentration, we hypothesize that more clustering occurs and the chemical equilibrium shifts toward the cis isomer. It is possible that such isomeric effects play a role in the liquid–liquid extraction of other species and the inclusion of such effects in flow sheet modeling may lead to a better description of the process.

Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a 3He spin filter as a spin analyzer for the neutrons scattered from the sample. The cell of the 3He spin filter gives a weak small-angle scattering intensity (background) and covers a sufficient solid angle for performing SANS experiments. The relaxation time of the 3He polarization is sufficient for continuous use for approximately 2 days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to the extremely large incoherent scattering cross section of hydrogen atoms in samples, is difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources such as the Japan Proton Accelerator Research Complex (J-PARC) and the US Spallation Neutron Source. It is anticipated that this work will contribute significantly to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC, particularly for systems involving competition between the coherent and incoherent scattering intensity.

A spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, i.e. the contribution of hydrogen atoms to a crystal's structure factor, has been developed. Crystals of L-glutamic acid were dispersed in a D-polystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization-dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

The nanostructure of oleyl acid phosphate (OLAP) in lubricant, which is an essential factor for understanding lubrication properties, was investigated using small-angle X-ray scattering (SAXS). SAX...

We compare the extraction performance of new extractant, fluorous phosphate tris(4,4,5,5,6,6,7,7,7-nonafluoroheptyl) phosphate (TFP) in the fluorinated diluent perfluorohexane, for Zr(IV) with a conventional organic extractant, tri-n-butyl phosphate (TBP) in n-octane. It is surprising that fluorinating TBP to TFP improved the extraction performance, as normally fluorinating the hydrocarbon substituents on neutral extractants tends to decrease the extraction strength. We examined the origin of the superior extraction performance of TFP by analyzing the equilibrium of the chemical reaction during the extraction. The equilibrium reaction of Zr(IV) with TFP is ZrNO34aq+3TFPflu ⇌ZrNO34TFP3flu, whereas that with TBP is ZrNO34aq+2TBPorg ⇌ZrNO34(TBP)2org. Phosphorus-31 nuclear magnetic resonance and infrared spectroscopy measurements of TFP and TBP showed similar electron densities at the phosphorus atom and vibration modes of the P=O group, implying similar coordination to Zr(IV). In addition, the concentrations of all components (Zr(IV), HNO3, and water) in the fluorous and organic phases after solvent extraction were evaluated by inductively coupled plasma-mass spectrometry, ion chromatography, and Karl-Fischer titration. The concentrations of water and HNO3 molecules in the fluorous phase become low during the Zr(NO3)4(TFP)3 extraction, indicating that water and HNO3 molecules do not preferentially interact with Zr(NO3)4(TFP)3 in contrast to Zr(NO3)4(TBP)2 in n-octane We speculate that the excellent performance originated from the stability of Zr(NO3)4(TFP)3 in the fluorous phase. Hence, TFP is expected to be used as an alternative extractant to TBP.

Dissipative structures often appear as an unstable counterpart of ordered structures owing to fluctuations that do not form a homogeneous phase. Even a multiphase mixture may simultaneously undergo one chemical reaction near equilibrium and another one that is far from equilibrium. Here, we observed in real time crystal seed formation and simultaneous nanocrystal aggregation proceeding from CeIV complexes to CeO2 nanoparticles in an acidic aqueous solution, and investigated the resultant hierarchical nanoarchitecture. The formed particles exhibited two very different size ranges. The hierarchically assembled structures in solutions were CeO2 colloids, viz. primary core clusters (1–3 nm) of crystalline ceria and secondary clusters (20–30 nm) assembled through surface ions. Such self-assembly is widespread in multi-component complex fluids, paradoxically moderating hierarchical reactions. Stability and instability are not only critical but also complementary for co-optimisation around the nearby free energy landscape prior to bifurcation.

A sensory system incorporated with an amplification function was developed for the detection of trace-level fluoride ions. This sensory system comprises two steps: amplification and chemiluminescence. These steps were linked with chemical reactions and were induced continuously. The process from amplification to chemiluminescence was accomplished in this system using fluoride ions. The amplification is based on a self-immolative system that permits the detection of emissions even at low fluoride ion concentrations for systems in which chemiluminescence cannot be induced in the absence of fluoride ions. The optimal ratio of the chemiluminescent compound and the amplifier was calculated to achieve efficient amplification.

The separation properties of Pt(IV) over Fe(III) in HCl solutions using N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide)amine (EHBAA) were investigated and then compared with those using the conventional extractant tri-n-octylamine (TOA). Also, the structural analyses of Pt(IV) in both of the aqueous (HCl solution) and organic (EHBAA in n-dodecane–2-ethylhexanol solution) phases were performed with EXAFS spectroscopy. The extractability of Pt(IV) was much higher with EHBAA than with TOA in the studied HCl concentration range (0.2–8 M HCl); additionally, EHBAA selectively extracted Pt(IV) over Fe(III) under the condition of [EHBAA] ⩽ 0.1 M and [HCl] ⩽ 1 M. The Pt(IV) loading capacity of 0.1 M EHBAA was about 9.2 g/L (about 0.05 M). Most of the Pt(IV) extracted with 0.1 M EHBAA from 1 M HCl was stripped with 0.1 M NaOH; the co-extracted Fe(III) was selectively scrubbed with distilled water. The structural studies indicated that the Pt(IV) extracted with EHBAA from 1 M HCl formed an ion-pair complex, [PtCl6]·(EHBAA·H)2.

Current methods for the extraction of rhodium carry the highest carbon footprint and worst pollution metrics of all of the elements used in modern technological applications. Improving upon existing methods is made difficult by the limited understanding of the molecular-level chemistry occurring in these processes, particularly in the hydrometallurgical separation step. While many of the precious metals can be separated by solvent extraction, there currently exist no commercial extraction reagents for Rh. This is due to its complicated mixed speciation upon leaching into hydrochloric acid, which gives rise to difficulties in designing effective reagents for solvent extraction. Herein we show that the diamidoamine reagent N-n-hexyl-bis(N-methyl-N-n-octyl-ethylamide)amine transports Rh(III) from aqueous HCl into an organic phase as the mono-aquated dianion [RhCl5(H2O)]2– through the formation of an outer-sphere assembly; this assembly has been characterized by experimentation (slope analysis, FT-IR and NMR spectroscopy, EXAFS, SANS, ESI-MS) and computational modeling. The paper demonstrates the importance of applying a broad range of techniques to obtain a convincing mode of action view for the complex processes involved in anion recognition in the solution phase. A consistent and comprehensive understanding of how the ligand operates to achieve Rh(III) selectivity over the competitor anion Cl− has emerged. This knowledge will guide the rational design of the next generation of extractants and thus offers promise for improving the sustainability of metal extraction from both traditional mining sources and the recycling of secondary source materials.

We report the hierarchical structure of zirconium hydroxide after aging at different temperatures to elucidate the factors governing zirconium solubility in aqueous solutions. Zirconium hydroxide solid phases after aging at 25, 40, 60, and 90 °C under acidic to alkaline conditions were investigated using extended X-ray absorption fine structure (EXAFS), wide- and small-angle X-ray scattering (WAXS and SAXS), and transmission electron microscopy (TEM) techniques to reveal the bulk and surface structures of the solid phases from the nanoscale to sub-microscale. After aging at 25 °C, the fundamental building unit of the solid phase was considered to be tetrameric and dimeric hydroxide species. These polynuclear species formed amorphous primary particles that are approximately 3 nm in size, which in turn formed aggregates that are hundreds of nanometers in size. This hierarchical structure was found to be stable up to 60 °C under acidic and neutral conditions and up to 40 °C under alkaline conditions. After aging at 90 °C under acidic conditions and at 60 and 90 °C under alkaline conditions, the WAXS and EXAFS measurements suggested the crystallization of the solid phase. The SAXS profiles and TEM observations supported the existence of crystallized large particles about 60 nm in size, and the appearance of the Guinier region in the SAXS profiles indicated that the crystallization of the amorphous primary particles leads to the reduction of the size of the large aggregates. The transformation of the solid-phase structure by temperature was discussed in relation to the solubility product to understand the solubility-limiting solid phase. The solubility of zirconium hydroxide after aging at different temperatures was governed not only by the size of the amorphous primary particles or crystallized large particles but also by their surface configuration.

This study uses small-angle neutron scattering (SANS) to elucidate the coordination structure of the complex of mono-acetyl-substituted dibenzo-20-crown-6-ether (ace-DB20C6) with cesium ions (Cs+). SANS profiles obtained for the complex of ace-DB20C6 and Cs+ (ace-DB20C6/Cs) in deuterated dimethyl sulfoxide indicated that Cs+ coordination resulted in a more compact structure than the free ace-DB20C6. The data were fitted well with SANS profiles calculated using Debye function for scattering on an absolute scattering intensity scale. For this theoretical calculation of the scattering profiles, the coordination structure proposed based on density functional theory calculation was used. Consequently, we conclude that the SANS analysis experimentally supports the proposed coordination structure of ace-DB20C6/Cs and suggests the following: (1) the complex of ace-DB20C6 and Cs+ is formed with an ace-DB20C6/Cs molar ratio of 1/1 and (2) the two benzene rings of ace-DB20C6 fold around Cs+ above the center of the crown ether ring of ace-DB20C6.

We present a method for fabricating photonic crystals (PCs) by polymerization-induced microphase separation of block copolymers (BCPs). Molecular weight of BCP for PCs is so large that it has been difficult for conventional solution casting and annealing methods to complete the microphase separation to form periodically ordered submicron structures. Our method overcomes the difficulty by inducing the microphase separation and transitions during the polymerization, when the molecular weight of the BCPs is small enough for the microphase separation and transitions. The microphase-separated structure is then enlarged while maintaining the self-similarity. We succeeded in fabricating PCs with reflection wavelength λm ≈ 1000 nm and a full width at half-maximum Δλ = 0.05λm by living-radical bulk block copolymerization of poly(methyl methacrylate)-block-polystyrene.

We performed neutron polarization analysis (NPA) of extracted organic phases containing complexes, comprised of Zr(NO3)4 and tri-n-butyl phosphate, which enabled decomposition of the intensity distribution of small-angle neutron scattering (SANS) into the coherent and incoherent scattering components. The coherent scattering intensity, containing structural information, and the incoherent scattering compete over a wide range of magnitude of scattering vector, q, specifically when q is larger than q* ≈ 1/Rg, where Rg is the radius of gyration of scatterer. Therefore, it is important to determine the incoherent scattering intensity exactly to perform an accurate structural analysis from SANS data when Rg is small, such as the aforementioned extracted coordination species. Although NPA is the best method for evaluating the incoherent scattering component for accurately determining the coherent scattering in SANS, this method is not used frequently in SANS data analysis because it is technically chall...

We are developing time-resolved grazing-incidence small-angle scattering (GI-SAXS) system using a soft X-ray laser. As a first step, we carried out GI-SAXS measurements of optical grating and craters produced on gold surface by femtosecond laser ablation . We succeeded in observing the diffraction spots from the grating as expected, but the diffuse scattering from the craters was hidden in thermal noises of a soft X-ray charge-coupled device camera.

We present evidence that the organic/third phase transition, as may be observed in the Plutonium Uranium Reduction EXtraction process (PUREX) at high metal loading, is an unusual transition between two isotropic, bi-continuous micro-emulsion phases. As this system contains so many components, however, we seek first to investigate the properties of a simpler system, viz. the related metal-free, quaternary system of water/n-dodecane/nitric acid/tri-butyl phosphate (TBP). Under appropriate conditions, this system exhibits three coexisting phases, namely the light organic phase, the third phase and the aqueous phase. In this paper, we focus on the two phase coexistence between the light organic and the third phase. Using Gibbs Ensemble Monte Carlo (GEMC) simulations, we find phase-coexistence between a phase rich in nitric acid and dilute in n-dodecane (the third phase) with a phase more dilute in nitric acid and rich in n-dodecane (the light organic phase). The compositions and densities of these two co-existing phases are in good agreement with experiment. Because the systems are dense and the molecules involved are not simple, the particle exchange rate in the GEMC simulation can be rather low. To show that the system, at a composition intermediate between that of the observed third and organic phases, is indeed unstable with respect to phase separation, we use the Bennett acceptance ratio method to calculate the Gibbs energies of the homogeneous phase and the weighted average of the two co-existing phases, where the compositions of these phases were taken both from GEMC and from experiment. Both demixed states have a statistically significant lower Gibbs energy than the uniform, mixed phase, providing confirmation that GEMC correctly predicts phase separation. Snapshots from the simulations as well as the cluster analysis of the organic and third phases reveal structures akin to bi-continuous micro-emulsion phases, where the polar species reside within a mesh whose surface consists of amphiphilic TBP molecules. The non-polar n-dodecane molecules are outside this mesh. The large-scale structural differences between the two phases lie solely in the dimensions of the mesh. Evidence for the correctness of these structures comes from small-angle X-ray scattering (SAXS), where the profiles obtained for both the organic and third phases agree well with those calculated from simulation. Finally we look at the microscopic structures of the two phases. In the organic phase, the basic motif is that of one nitric acid molecule hydrogen bonded to a TBP. In the third phase, the most common structure was that of the hydrogen bonded chain TBP–HNO3–HNO3. A cluster analysis provides evidence that the TBP forms an extended, connected network in both phases. Studies of the effects of metal ions on these systems will be presented elsewhere, but suffice it to say here that these ions do not change the basic bi-continuous structure of the phases. The metal ions reside inside the mesh along with the other polar molecules.

Using N,N,N',N'-tetra-2-ethylhexyl-thiodiglycolamide (TEHTDGA) in n-dodecane as the extractant, we compared the percentages of Pd(II) extracted from HCl and HBr solutions, and analyzed the structures of the Pd(II)-extractant complexes. For comparison, similar experiments were performed with di-n-hexyl sulfide (DHS), a well-known sulfide-type extractant. TEHTDGA extracted Pd(II) from both HCl and HBr solutions much faster than DHS. The Pd(II)/(TEHTDGA or DHS) stoichiometry in the organic phase was 1:2. For TEHTDGA, the extractability of Pd(II) from HBr solution was inferior to that from HCl solution, whereas the opposite was true for DHS. However, FT-IR spectroscopy and EXAFS measurements indicated that the inner-sphere structure of Pd(II) in the TEHTDGA complex was almost the same as that in the DHS system: in both cases, two of the halide ions in the tetrachloro- or tetrabromopalladate(II) ion were replaced by the sulfur atoms of two extractant molecules.

A calcium (Ca)-deficient hydroxyapatite was investigated for its potential to remove Sr2+ from environmentally relevant water. We conducted sorption tests on solutions containing magnesium ion (Mg2+) and calcium ion (Ca2+) as competing cations at a strontium ion (Sr2+) concentration of 0.05 mmol/L. The Ca-deficient hydroxyapatite maintained a high Sr2+ sorption ratio of above 80% in the presence of Mg2+ and Ca2+ at the concentrations between 0.1 and 1.0 mmol/L, whereas the stoichiometric hydroxyapatite showed a lower ratio even in the presence of small amounts of Mg2+ and Ca2+ (72% for Mg2+ and 51% for Ca2+ at 0.1 mmol/L). For solutions with various Sr2+ concentrations between 0.01 and 10 mmol/L, Ca-deficient hydroxyapatite exhibited a higher Sr2+ sorption ratio than stoichiometric hydroxyapatite. The bonding states of Sr2+ on the Ca-deficient hydroxyapatite were evaluated by extended X-ray absorption fine structure measurements. The results indicated that there are specific sorption sites in Ca-deficient hydroxyapatite where Sr2+ is stably and preferentially immobilized.

We have succeeded in observing Fe-ion-beam induced nanostructural change of MA956 oxide dispersion-strengthened (ODS) steel using anomalous small-angle X-ray scattering (ASAXS) diffractometry. The ASAXS curve shows a power-law scattering that follows the Porod’s law and an overlapped shoulder peak at the magnitude of scattering vector, Q, around 0.6 nm−1. As the X-ray energy approaches the absorption K-edge of Cr (5.990 keV), the intensity of the power-law scattering slightly decreases, but that of the shoulder peak remarkably increases. From these results, the power-law scattering is attributed to Cr-poor scatterers with a radius much larger than 5 nm, and the shoulder peak is attributed to Cr-rich α′ precipitates with a mean radius of 2.8 nm. After the ion-beam irradiation, intensity of the power-law scattering is nearly doubled, but the shoulder peak remains unchanged within an error of 2%. The latter result indicates that the irradiation-induced changes of radius and inter-precipitation distance of the α′ precipitates are smaller than 10%, and the change of their interface thickness is less than 0.5 nm. In this way, our ASAXS results guarantee an absence of irradiation-induced nanostructure change of specific kinds of precipitates together with statistical errors, while observing changes of other precipitates.

The effect of cesium (Cs) adsorption on the mesoscopic structure of the clay minerals vermiculite and weathered biotite (WB) in suspensions was elucidated by small-angle X-ray scattering (SAXS). The clay minerals form multilayered structures, and the Cs cations (Cs(+)) are strongly adsorbed in the interlayer space of the soil clays, in particular vermiculite and WB. SAXS was used to monitor the relationship between Cs(+) adsorption at the clay interlayers and the structural changes at length scales from 1 to 1000 Å. The variation in the distance between the neighboring clay sheets and the spatial arrangement of the clay sheets with and without Cs(+) were clarified. Our quantitative analyses revealed that the number of stacked layers of pure vermiculite was decreased by Cs(+) addition, whereas that of WB increased. Moreover, the average distance between the neighboring layers of vermiculite in suspension was larger than that of WB, which reflects the different conditions of Cs(+) intercalation. These findings provide fundamental insights that are important for predicting the environmental fate of radioactive Cs in contaminated regions and for developing methods for extracting Cs from soil.

Here it is demonstrated that mesoporous silicas (MPSs) can be used as effective "topological crosslinkers" for poly(N-isopropylacrylamide) (PNIPA) hydrogels to improve the mechanical property. Three-dimensional bicontinuous mesporous silica is found to effectively reinforce the PNIPA hydrogels, as compared to nonporous silica and two-dimensional hexagonally ordered mesoporous silica.

We developed a novel fluorescence labeling technique for quantification of surface densities of atom transfer radical polymerization (ATRP) initiators on polymer particles. The cationic P(St-CPEM-C4DMAEMA) and anionic P(St-CPEM) polymer latex particles carrying ATRP-initiating chlorine groups were prepared by emulsifier-free emulsion polymerization of styrene (St), 2-(2-chloropropionyloxy)ethyl methacrylate (CPEM), and N-n-butyl-N,N-dimethyl-N-(2-methacryloyloxy)ethylammonium bromide (C4DMAEMA). ATRP initiators on the surface of polymer particles were converted into azide groups by sodium azide, followed by fluorescent labeling with 5-(N,N-dimethylamino)-N′-(prop-2-yn-1-yl)naphthalene-1-sulfonamide (Dansyl-alkyne) by copper-catalyzed azide-alkyne cycloaddition (CuAAC). The reaction time required for both azidation of ATRP-initiating groups and successive fluorescence labeling of azide groups with Dansyl-alkyne by CuAAC were investigated in detail by FTIR and fluorescence spectral measurement, respectively. The ATRP initiator densities on the cationic P(St-CPEM-C4DMAEMA) and anionic P(St-CPEM) particle surfaces were estimated to be 0.21 and 0.15 molecules nm−2, respectively, which gave close agreement with values previously determined by a conductometric titration method. The fluorescence labeling through click chemistry proposed herein is a versatile technique to quantify the surface ATRP initiator density both on anionic and cationic polymer particles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4042–4051

graphical a bstract abstract This study was investigated the trace lanthanide (Nd(III), Eu(III) and Yb(III)) sorption and recovery from wastewater streams by novel hybrid adsorbent (HA). The HA was prepared through functional immobi- lization of N-octyl-N-tolyl-1,10-phenanthroline-2-carboxaide into large and cage-pored mesoporous silica monolith. The adsorbent was stable and easy to adsorb and recover of lanthanide ions by complex- ation mechanism. The experiments were investigated to determine the effects pH, ions selectivity and lanthanide ions coordination by XAFS spectra. The lanthanide sorption were well fitted the Langmuir sorption isotherm model and indicated the maximum sorption capacities were 176.06, 163.13, and 161.81 mg/g for Yb(III), Eu(III) and Nd(III), respectively. The lanthanide sorption was not affected by the presence of monovalent and divalent of sodium, potassium, calcium, magnesium, chloride, sulfate and nitrate ions due to strong tendency to form stable complexation with trivalent lanthanide. However, aluminum was strongly competed of lanthanide ions sorption due to trivalent characteristic and\ lantha- nide sorption was greater than half of the sorption capacity without Al 3+ interfering. The EXAFS data revealed that O and N donor atoms of the HA were strongly coordinated to lanthanide ions to form stable complexes. However, the bond distance of O donor atoms was shorter than N donor atoms. The adsorbed lanthanide ions were eluted with stripping agents and the adsorbent was regenerated into initial form for subsequent sorption operations after rinsing with water. The results suggested that the HA may find promising applications for selective sorption and recovery of lanthanide ions from wastewater effluents. 2013 Elsevier B.V. All rights reserved.

This study aims to develop a highly selective Lewis base adsorbent to investigate the selective sorption and recovery of Eu(III) and Sm(III) from wastewater. The oxygen and nitrogen donor atoms containing Lewis base N -methyl- N -phenyl-1,10-phenanthroline-2-carboxamide (MePhPTA) ligand was synthesized and subsequently an adsorbent was prepared by direct immobilization onto mesoporous silica. Determined maximum adsorption capacities were 125.63 and 124.38 mg/g for Eu(III) and Sm(III), respectively. Experiments with mixed-cations solutions showed that the sequence of preferential adsorption was Eu(III) > Sm(III). The lanthanide sorption by hybrid Lewis base adsorbent (HyLBA) was not adversely affected by the presence of sodium, potassium, calcium, magnesium, chloride, sulfate and nitrate ions due to strong affinity between hard Lewis acid lanthanide and hard Lewis base adsorbent. The crystallography for the Sm-MePhPTA complex suggested that MePhPTA was strongly coordinated to Sm(III) with oxygen and nitrogen by forming a stable complex with two 5-membered rings. The data clarified that bond lengths between Sm(III) and amide oxygen (2.475 A) were shorter than Sm N (2.662 A) in phenanthroline moiety indicating strong oxygen driven HyLBA. The results suggested that HyLBA has a good prospect of promising applications for separation/sorption of lanthanide ions from effluents.

A refined model for tri-n-butyl phosphate (TBP), which uses a new set of partial charges generated from our ab initio density functional theory calculations, has been proposed in this study. Molecular dynamics simulations are conducted to determine the thermodynamic properties, transport properties, and the microscopic structures of liquid TBP, TBP/water mixtures, and TBP/n-alkane mixtures. These results are compared with those obtained from four other TBP models, previously described in the literature. We conclude that our refined TBP model appears to be the only TBP model from this set that, with reasonable accuracy, can simultaneously predict the properties of TBP in bulk TBP, in organic diluents, and in aqueous solution. The other models only work well for two of the three systems mentioned above. This new TBP model is thus appropriate for the simulation of liquid-liquid extraction systems in the nuclear extraction process, where one needs to simultaneously model TBP in both aqueous and organic phases. It is also promising for the investigation of the microscopic structure of the organic phase in these processes and for the characterization of third-phase formation, where TBP again interacts simultaneously with both polar and nonpolar molecules. Because the proposed TBP model uses OPLS-2005 Lennard-Jones parameters, it may be used with confidence to model mixtures of TBP with other species whose parameters are given by the OPLS-2005 force field.

We have investigated the origin of a specific polymerization loci that yielded copolymer particles with a bimodal gel permeation chromatographic profile in the early stage of miniemulsion polymerization of styrene (St) with the polymerizable surfactant N-n-dodecyl-N-2-methacryloyloxyethyl-N,N-dimethylammonium bromide (C12DMAEMA). The formation of particles by miniemulsion polymerization using C12DMAEMA was investigated as a function of the polymerization time (tp) and was compared with that using the nonpolymerizable surfactant cetyltrimethylammonium bromide (CTAB). St was miniemulsified with C12DMAEMA or CTAB and was polymerized with either a water-soluble initiator, 2,2′-azobis(2-amidinopropane) dihydrochloride (V50), or an oil-soluble initiator, 2,2′-azobis(isobutyronitrile) (AIBN), at 60 °C in the presence of polystyrene (PSt) as a hydrophobe. Gel permeation chromatography (GPC) and elemental analysis indirectly predicted two different polymerization loci in the St/C12DMAEMA/V50 polymerization system....

We developed a theoretical model for a self-assembling telechelic poly(N-isopropylacrylamide) (PNIPAM) carrying octadecyl end-groups in aqueous solution, as a function of temperature and concentration, on the basis of small-angle neutron scattering data. In solutions of concentration 10 g L -1 at temperatures between 10 and 20 °C, the telechelic PNIPAM of molecular weight of 22 , 200 g mol -1 associates in the form of flower micelles containing about 12 polymer chains. Micelles have a 3 -layered core-shell morphology with an inner core consisting of the octadecyl units, a dense inner shell consisting of partly collapsed PNIPAM chains, and an outer shell of swollen hydrated PNIPAM chains. Drastic changes in the scattering profile of the solution heated above 31 °C are attributed to the formation of mesoglobules of diameter of 100 nm consisting of about 1000 polymer chains. In solutions of lower concentration (1 g L -1 ), association of flower micelles and mesoglobules is suppressed. The structure of the individual flower micelles and mesoglobules is not affected by changes in concentration. In solutions of 50 g L -1 , a peak attributed to a correlation between flower micelles appears in the scattering profiles at low temperature (10 °C). Despite the difference in the population of intermicellar bridges, the overall temperature dependence of the scattering profile at 50 g L -1 remains similar to that at 10 g L -1 .

In situ and time-resolved small-angle neutron scattering (SANS) was employed for the elucidation of star polymer formation mechanism via linking reaction of living linear polymers in ruthenium-catalyzed living radical polymerization. Here, methyl methacrylate (MMA) was first polymerized with R−Cl/RuCl2(PPh3)3/tribuylamine (n-Bu3N) initiating system, followed by the addition of ethylene glycol dimethacrylate (EGDMA: 3) as a linking agent. After the in situ addition of a small amount of 3 to living linear PMMA, the SANS analysis revealed the following three steps: (process II-1) formation of block copolymers (4) and competitive formation of the small star polymers via the linking reaction of 4 and 4; (process II-2) star−star linking of the small star polymers into star polymers and putting 4 into the core of the star polymers, leading to formation of the microgel-core star polymers; (process II-3) growth of the microgel-core star polymers (5) via placement of 4 into the microgel-core star polymers. Furtherm...

Poly(ethylene glycol)-block-poly(N-isopropylacrylamide) (PEG-b-PNIPAAm) was synthesized by radical polymerization of N-isopropylacrylamide (NIPAAm) from the radically activated chain ends generated...

The phase equilibrium property and structural and dynamical properties of pig cornea were studied by macroscopic observation of swelling behavior, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS) under various conditions. It was found that the corneal gel collapses into a compact state isotropically or anisotropically depending on the external conditions. The corneal gel collapses uniformly into a compact state at a temperature above 55 degrees C because of the denaturation of collagen, whereas it collapses along an axis parallel to the optic axis with increasing NaCl concentration. Anisotropic deswelling was also observed during desiccation. SAXS measurements revealed that the periodicity of the collagen fiber of the cornea does not change even at higher NaCl concentration, which indicates that hydration and dehydration resulting from changes in salt concentration simply cause swelling and deswelling of the glycosaminoglycan (GAG), which is located between the regular two-dimensional lattices of collagen fibers, which obliges the change in thickness. From observations of the dynamics of light scattered by the corneal gel, intensity autocorrelation functions that revealed two independent diffusion coefficients were obtained. Divergent behavior in the measured total scattered light intensities and diffusion coefficients with varying temperature was observed. That is, a slowing of the dynamic modes accompanied by increased "static" scattered intensities was observed. This is indicative of the occurrence of a phase transition as a function of temperature.

We have studied the dynamics of a morphology transition of domains in a reactive system composed of A−B block copolymer and B monomer, where polymerization occurs at the end of the B subchain of th...

On the basis of results from a small-angle neutron scattering (SANS) study of aqueous solutions of a telechelic PNIPAM with octadecyl end groups, we developed a theoretical model of the self-assembly of this polymer in water as a function of temperature and concentration. This model leads us to the following description. In solutions of concentration 10 g L−1 kept between 10 and 20 °C, telechelic PNIPAMs (Mn = 22 200 g mol −1) associate in the form of flower micelles, containing about 12 polymer chains, assembled in a three-layered core−shell morphology with an inner core consisting of the octadecyl units, a dense inner shell consisting of partly collapsed PNIPAM chains, and an outer shell of swollen hydrated chains. Drastic changes in the scattering profile of the solution heated above 31 °C are attributed to the formation of mesoglobules (diameter of ∼40 nm) consisting of about 1000 polymer chains. On further heating, the aggregation number of the mesoglobules increases. It reaches a value of ∼9000 at 3...

Living Polymerization Induced Macro- and Microdomain Investigated by Focusing Ultra-small-angle Neutron Scattering

SANS-J (a pinhole small-angle neutron scattering spectrometer at research reactor JRR3, Tokai, Japan) was reconstructed as a focusing and polarized neutron small-angle scattering spectrometer (SANS-J-II). By employing focusing lenses of a biconcave MgF2 crystal or of a sextupole permanent magnet and a high-resolution photomultiplier, the minimum accessible magnitude of the scattering vector qmin was improved from 3 × 10−3 A−1 to an ultra-small-angle scattering (USAS) of 3 × 10−4 A−1. Compared with a Bonse–Hart double-crystal method, the advantages of focusing USAS are the efficient detection of anisotropic USAS with an area detector, an improvement in q resolution Δq/q at conventional magnitudes of the scattering vector q ~ 10−3 A−1 and a gain in neutron flux in the conventional q region of q ~ 10−3 A−1.

Reversible addition–fragmentation chain transfer (RAFT) living radical polymerization of poly(methyl methacrylate)-block-polystyrene (PMMA-b-PS) was investigated by a combined method of gel permeation chromatography (GPC) and in situ and time-resolved ultra small-angle neutron scattering (tr-USANS) measurements. GPC enables us to examine a growing single molecule as a function of polymerization time, with respect to monomer conversion, molecular weight (Mn) and polydispersity index (Mw/Mn) of PMMA-b-PS. On the other hand, tr-USANS, observing in meso-length scales from nm to µm, reveals polymerization-induced molecular self-assembly, such as microphase separation by PMMA-b-PS or macrophase separation between PMMA-b-PS and homo-polystyrene (by-product). By combining these two experimental methods, we elucidated that RAFT living polymerization was retarded by micro- and macrophase separations.

To address the question as to how small-angle scattering is effectively applied to the cell, i.e., ahierarchically ordered system comprising multi-components of macro and small molecules, the size ofwhich ranges from 100 μm to several μm, we reconstructed SANS-J (pinhole small-angle neutronscattering spectrometer at research reactor JRR3, Tokai) to focusing & polarized neutron small-anglespectrometer (SANS-J-II), by employing focusing neutron lenses and high resolution photomultiplier.Consequently, an accessible minimum wave number qmin was improved from 3×10-3 A-1 to mediumultra-small angle scattering of 3×10-4 A-1. The focusing USANS method, thus developed, is crucialto fill the gap in wave number q between those covered by a double crystal method and by a conventionalpin-hole method.

By employing focusing lenses of sextupole permanent magnet and biconcave MgF2 crystal, and high-resolution photomultiplier, SANS-J (pinhole small-angle neutron scattering spectrometer at research reactor JRR3, Tokai) was reconstructed to focusing and polarized neutron ultra-small-angle scattering spectrometer (SANS-J-II). Consequently, an accessible minimum wave number qmin was improved from 3×10−3 A−1 to 3×10−4 A−1. Furthermore, we added 3He sub-detectors with an analyzer super mirror at a sample position. With this setup, we perform polarization analysis at high q (>0.2 A−1) in order to quantitatively discriminate spin incoherent scattering from hydrogen or to perform spin contrast variation, by a dynamic nuclear polarization method (>0.2 A−1).

A new tandem analyzer crystals system was introduced on Bonse–Hart ultra-small-angle neutron-scattering spectrometer at research reactor JRR-3, Tokai, Japan. Conventional Bonse–Hart setup consumes a considerable time to measure a scattering profile of whole q range (2×10 −4 nm −1 q −2 nm −1 , where q denotes magnitude of scattering vector) due to the step scan system, in which the scattered neutrons from the sample and having different q are measured step by step. To overcome this difficulty two analyzer channel-cut silicon perfect crystals were settled in tandem and each of them diffracted the scattering of different q . In consequence, a simultaneous detection at two different q positions was realized and the measurement time was reduced to half.

This investigation focused on the self-assembly of poly(N-isopropylacrylamide)-block-poly(ethylene glycol) (PNIPA-b-PEG) in water. We distinguish four regions in the phase diagram: a transparent sol, opaque sol, opaque gel, and syneresis. Small-angle neutron scattering measurements revealed that microphase separation occurs above 17 ∘ C to form disordered micelles, which includes a range of states from (i) asymmetric swelling to (ii) micelle formation with only short-range liquid-like order. This result may be attributed to the action of water, which starts to behave as a selective solvent for PEG blocks; the PEG chains are more swollen with water than are the PNIPA chains.