Cation Exchange Mechanism Research Articles

Extraction of Cobalt and Lithium from Sulfate Solution Using Di(2-ethylhexyl)phosphoric Acid/Kerosene Mixed Extractant

The solvent extraction behavior of cobalt and lithium from mixed sulfate solution using di(2-ethylhexyl)phosphoric acid (D2EHPA)/kerosene as extractant system has been investigated. The effect of different process parameters such as pH of feed solution, extractant concentration, cobalt and lithium ion concentrations in the feed solution have been studied. Extraction equilibrium constants have been calculated and found to be log Kex Co = –2.01 and log Kex Li = –2.42. The highest separation factor of 292 was achieved using 1.59 M D2EHPA at pH 1.85 from mixed sulfate solution. 93.9% of cobalt and 11.4% lithium was co-extracted from 0.01 M cobalt and lithium sulfate solution. Extraction of cobalt-lithium by D2EHPA is affected by cation exchange mechanism, cobalt is extracted as [Co(HA2)2] and [CoA2] depending on the metal concentration in the feed solution while the lithium is extracted as [Li(A2H)]. Quantitative extraction of cobalt was achieved in two-stage counter-current batch extraction (with McCabe–Thiele plot) using 0.477 M D2EHPA at an O : A phase ratio of 1. The data obtained from loaded organic and raffinate indicate a composition which reveals nearly complete extraction of cobalt and rejection of lithium resulting significant separation of these elements from mixed sulfate solution.

Study of interactions between rhodamine B and a beidellite-rich clay fraction

AbstractThe interaction between a basic dye, rhodamine B, and a separated fine fraction from natural clay was studied. Chemical analysis, X-ray diffraction and Fourier-transform infrared spectroscopy confirmed the predominance of beidellite in the fine clay fraction. The interaction of rhodamine B with the fine clay fraction showed that sorption was fast and followed a pseudo-second-order kinetic model. The comparison between sorbed rhodamine B amounts as a function of the various experimental parameters such as pH, sorbent mass, dye concentration and the presence of competing ions suggests that: (1) the sorption process is largely pH-dependent; (2) significant competition is observed between the dye and the Ca2+ and Mg2+ ions; (3) the sorption proceeds, principally, by a cation-exchange mechanism; and (4) the sorption capacity of the fine fraction in the presence of competing cations such as Ca2+ is ~0.28 mmol g–1.

Fabrication and Characterization of a Reversed-Phase/Strong Cation Exchange Stationary Phase Gradient

Continuous stationary phase gradients for liquid chromatography (LC) have been recently shown to be a promising method of altering selectivity. In this work, we present the first multicomponent continuous stationary phase gradient for separations involving both reversed-phase (RP) and strong cation exchange (SCX) mechanisms. These columns are fabricated using a two-step methodology based on controlled rate infusion (CRI). First, destructive CRI creates a gradient of excess silanol groups along a uniform C18 column. Next, these columns are infused with 3-mercaptopropyltrimethoxysilane (MPTMOS), which bonds to the excess silanol groups. The terminal thiols of the MPTMOS ligands are oxidized with H2O2 to create the sulfonate functionality (SO3−) needed for SCX separations. The success of the modification procedure is characterized by thermogravimetric analysis and X-ray photoelectron spectroscopy. The stability of the C18-SO3− gradients were found to have less than 5 % retention loss and the column-to-column reproducibility had a relative standard deviation under 9 %. The peak asymmetry factors for seven biogenic amines were found to be between 1.03 ± 0.04 to 1.30 ± 0.02, which illustrates minimal peak tailing due to poor packing and residual silanol groups. Characterization of the gradient columns using an isocratic mobile phase showed a unique elution order compared to a uniform C18 and SO3− columns. At lower counterion concentrations, more than 48 % of the overall retention on the gradient stationary phase is due to a SCX mechanism. Meanwhile, the RP mechanism was shown to predominate at higher counterion concentrations on the gradient columns (SCX retention contribution less than 40 %). Coupling the stationary phase gradient to a salt gradient in the mobile phase showed that the gradient phase provides a unique, intermediate selectivity to the uniform C18 and SO3− columns. Under an ACN mobile phase gradient, a significant increase (p < 0.003) in the retention times of three biogenic amines (15 – 16 %) was observed when the multicomponent gradient was oriented to have a high SO3− ligand density near the detector. This work serves as a proof-of-concept design for a multicomponent stationary phase gradient to continue fundamental studies into retention and encourage novel applications.

Atomic deciphering of cation exchange mechanism in upconversion nanoparticles

Transition metal ion doping in upconversion nanoparticles (UCNPs) provides an effective way to enhance the luminescence for their wide array of applications. However, the doping sites of transition metal ions have not been comprehensively explored, and commonly assumed that transition metal ions replace the trivalent lanthanides within the lattice. Here we report that cation exchange of transition metal (Mn2+) in β-NaYF4:Yb3+/Er3+ UCNPs occurs through alkaline metal (Na+) replacement, via 2Na+↔ Mn2+ + Vacancy reaction. This process distorts the LnF9 polyhedrons and tailors the surrounding environment around the trivalent lanthanides, thereby improving the upconversion intensity from active lanthanides. Further confirmed by core-shell design and spectroscopic study, we prove that the transition–alkaline metal exchange enables both the emission enhancement and transition probability variation of activators.

Strong hydrogen bonding in a dense hydrous magnesium silicate discovered by neutron Laue diffraction.

A large amount of hydrogen circulates inside the Earth, which affects the long-term evolution of the planet. The majority of this hydrogen is stored in deep Earth within the crystal structures of dense minerals that are thermodynamically stable at high pressures and temperatures. To understand the reason for their stability under such extreme conditions, the chemical bonding geometry and cation exchange mechanism for including hydrogen were analyzed in a representative structure of such minerals (i.e. phase E of dense hydrous magnesium silicate) by using time-of-flight single-crystal neutron Laue diffraction. Phase E has a layered structure belonging to the space group R 3 m and a very large hydrogen capacity (up to 18% H2O weight fraction). It is stable at pressures of 13-18 GPa and temperatures of up to at least 1573 K. Deuterated high-quality crystals with the chemical formula Mg2.28Si1.32D2.15O6 were synthesized under the relevant high-pressure and high-temperature conditions. The nuclear density distribution obtained by neutron diffraction indicated that the O-D dipoles were directed towards neighboring O2- ions to form strong interlayer hydrogen bonds. This bonding plays a crucial role in stabilizing hydrogen within the mineral structure under such high-pressure and high-temperature conditions. It is considered that cation exchange occurs among Mg2+, D+ and Si4+ within this structure, making the hydrogen capacity flexible.

Electrospun Polystyrene/LDH Fibrous Membranes for the Removal of Cd2+ Ions

Layered double hydroxides (LDHs) have been extensively studied for a broad range of applications because of their ease of synthesis and chemical modifications. The chemical and crystal structure of LDH provides opportunities of combination with polymers forming nanocomposites. In the current study, MgAl-LDH particulates have been incorporated into micro- and nanofibers of polystyrene (PS) using an electrospinning processing technique of their respective homogeneous solutions. The effect of the varying proportions of LDH and PS on the structure, morphology, and thermal properties of the fabricated LDH-PS fibrous membranes has been investigated. The potential application of the optimally fabricated LDH-PS fibrous membranes in the removal of Cd2+ ions from aqueous media has been evaluated as well. Results showed the possibility of loading the PS fibrous membranes with up to 60 wt% of LDH particulates, which in turn modified the thermal stability and integrity of the produced fibrous membranes. Due to the high hydrophobicity of the PS fibrous matrix, no changes in the crystal structure of the LDH inclusions were observed. Both as-prepared LDH particulates and optimally prepared LDH-PS fibrous membranes showed a high potential for the removal of Cd2+ ions from aqueous media. This is attributed to a cation-exchange mechanism involving the adsorption of Cd2+ ions from a solution with the preferential leakage of Al3+ ions from the crystal structure of LDH.

Extraction of Lanthanides(III) along with Thorium(IV) from Chloride Solutions by N,N-di(2-Ethylhexyl)-Diglycolamic Acid

ABSTRACT The extraction of Nd(III), Gd(III), and Er(III), which represent light, middle, and heavy lanthanides, respectively, from chloride solutions has been carried out by using N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA, HA) diluted in kerosene as the organic phase. The results from the slope analysis method indicate that the extraction of Ln(III) with HDEHDGA is mainly governed by the cation-exchange reaction mechanisms in the low pH region (pH 1.2–2.7). The obtained data reveal that the extracted species in the organic phase might be LnA3∙HA(1~2), which consist of a core of 1:3 LnA3 complex and one additional neutral HA molecule for light Ln(III) or two for heavy Ln(III) associated with the core in the outer coordination sphere. The dependency on the temperatures indicates that the extraction of Ln(III) with HDEHDGA is exothermic and is mainly driven by the exothermic enthalpies crossing the whole Ln(III) series. The extraction of the whole Ln(III) series (except for Pm(III)) and Th(IV) has also been evaluated. HDEHDGA provides remarkable extraction capability with considerable separation factors (SF) for adjacent light Ln(III) pairs (SFCe/La = 6.8, SFPr/Ce = 3.3, SFNd/Pr = 2.5, and SFSm/Nd = 3.5), but relatively poor selectivity for the adjacent heavy Ln(III) pairs. It also presents very good selectivity/extractability for Th(IV) over the light Ln(III) ions (SFTh/La = 1362 and SFTh/Ce = 200). These properties make HDEHDGA a promising extractant for separating Th(IV) from light Ln(III) ions and for separating light Ln(III) ions from each other, which coexist significantly in some Rare Earth (RE) minerals, especially monazite and bastnaesite.

Extraction/removal of uranium, U(VI) from chloride solutions by an environment-friendly extractant

The extraction/removal of uranium U(VI) from chloride solutions have been investigated in the pH region by using N, N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA, HA) as an environment-friendly extractant. The influence of acid concentration in the aqueous phase, the ligand concentration in the organic phase, and the temperature on the extraction of U(VI) have been studied. The results from slope analysis methods reveal that the extraction of uranium is strongly pH-dependent and directed by cation-exchange mechanism. The proposed composition of the extracted complex species is UO2A2·HA with a core UO2A2 and one protonated ligand molecule binding to the second coordination sphere of the metal ion via hydrogen bonding. The extraction thermodynamic data demonstrate an exothermic reaction. The considerably high extraction affinity for uranium makes the HDEHDGA/kerosene system a promising candidate for the purification of water solutions from radioactive pollutants.

A new diphosphonic acid extractant N,N-n-octylamine di(methylene phenylphosphinic acid) for extraction and separation of zirconium and hafnium in hydrochloric acid

Nuclear grade zirconium and hafnium are the key to promoting the development of nuclear industry. We designed and synthesized a new diphosphonic acid extractant N,N-n-octylamine di(methylene phenylphosphinic acid) (OADMPPA) with excellent extraction ability and priority for extraction of zirconium. This paper focused on the changes in extraction mechanisms and composition of complexes. With increasing concentration of HCl, cation exchange mechanism gradually changed into solvation mechanism, and complexes converted in the order of ZrOA, Zr(HA)2Cl2 and ZrCl4·H2A. Compared with bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272), OADMPPA could increase the extraction rates of zirconium and hafnium by 7.2 and 12.6 times.

Synthesis of Poly(methacrylic acid)/Montmorillonite Hydrogel Nanocomposite for Efficient Adsorption of Amoxicillin and Diclofenac from Aqueous Environment: Kinetic, Isotherm, Reusability, and Thermodynamic Investigations.

Herein, a simplistic redox polymerization strategy was utilized for the fabrication of a poly(methacrylic acid)/montmorillonite hydrogel nanocomposite (PMA/nMMT) and probed as a sorbent for sequestration of two pharmaceutical contaminants, viz., amoxicillin (AMX) and diclofenac (DF), from wastewater. The synthesized hydrogel nanocomposite was characterized by the Fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, and transmission electron microscopy techniques to analyze structural characteristics and sorption interactions. The efficacy of PMA/nMMT was thoroughly investigated for the sequestration of AMX and DF from the aquatic phase with a variation in operative variables like agitation time, sorbent dosage, pH, and initial sorbate concentration. The reaction kinetics was essentially consistent with the pseudo-second-order model with rate dominated by the intraparticle diffusion model as well as the film diffusion mechanism. The Freundlich isotherm appropriated the equilibrium data over the entire range of concentration. Thermodynamic investigation explored the spontaneous and endothermic nature of the process. The most possible mechanism has been explained, which includes electrostatic interaction, hydrogen bonding, cationic exchange, and partition mechanism. Economic feasibility, better sorption capacity (152.65 for AMX and 152.86 mg/g for DF), and efficient regeneration and reusability even after four consecutive sorption–desorption cycles ascertained PMA/nMMT as a potential sorbent for AMX and DF uptake from the aqueous phase.

Extraction of tetravalent uranium by N,N,N',N'-tetramethylmalonamide in ionic liquid

In this paper, the extractant N,N,N',N'-tetramethylmalonamide (TMMA) was used to extract tetravalent uranium (abbreviated as U(IV)) from aqueous nitric acid solution into ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][NTf2]) system. It is found that the distribution coefficient of U(IV) in [C4mim][NTf2] is improved to 23, and the single stage extraction efficiency is more than 95% at 1:1 vol phase ratio, compared with the traditional toluene system. While U(VI) could be hardly extracted from nitric acid solutions at a concentration between 1.0 and 3.0 M, U(IV) and U(VI) could be selectively separated in this system and separation factor (SFIV/VI) could reach 28. According to the slope analysis, each U(IV) ion probably bounds one TMMA molecule. For nitric acid at a concentration between 1.0 and 3.0 M, the extraction process of U(IV) might follow the cation exchange mechanism. It is also found that the U(IV) complex extracted into the ionic liquid phase could be very stable and maintain in the air for at least two weeks without being oxidized.

Competitive adsorption behaviour and mechanisms of cadmium, nickel and ammonium from aqueous solution by fresh and ageing rice straw biochars

In this study, competitive adsorption behaviour and mechanisms of Cd2+, Ni2+ and NH4+ by fresh and artificially ageing biochars produced from rice straw at 400 and 700 °C (RB400, RB700, HRB400 and HRB700) were investigated. Cd2+ competed with Ni2+ and NH4+ for the overlapped adsorption sites on the biochars. For Cd2+ and Ni2+ adsorption, cation exchange (Qci) and mineral co-precipitation (Qcp) were the primary mechanisms for the low-temperature and high-temperature biochars, respectively. However, the other potential mechanisms (Qco) made the greatest contributions to NH4+ adsorption (>60%). Cd2+ and Ni2+ competition increased the proportions of mineral co-precipitation (Qcp) and other potential mechanisms (Qco) but decreased that of cation exchange (Qci) mechanism. Biochar ageing increased the contribution of surface complexation (Qcf) mechanism, especially for the low-temperature biochars. This study indicated that biochar aging and types and states of adsorbates should be considered when biochars were applied to remove contaminants.

Batch Study of Cadmium Biosorption by Carbon Dioxide Enriched Aphanothece sp. Dried Biomass

The conventional method for cadmium removal in aqueous solutions (1–100 mg/L) is ineffective and inefficient. Therefore, a batch biosorption reactor using a local freshwater microalga (originating from an urban lake, namely, Situ Rawa Kalong-Depok) as dried biosorbent was tested. Biosorbent made from three kinds of cyanobacterium Aphanothece sp. cultivars (A0, A8, and A15) were used to eliminate cadmium (Cd2+) ions in aqueous solution (1–7 mg/L). The biosorbents were harvested from a photobioreactor system enriched with carbon dioxide gas of 0.04% (atmospheric), 8%, and 15% under continuous light illumination of about 5700–6000 lux for 14 d of cultivation. Produced dried biosorbents had Brunauer–Emmet–Teller (BET) surface area ranges of 0.571–1.846 m2/g. Biosorption of Cd2+ was pH and concentration dependent. Sorption was spontaneous (ΔG = −8.39 to −10.88 kJ/mol), exothermic (ΔH = −41.85 to −49.16 kJ/mol), and decreased randomness (ΔS = −0.102 to −0.126 kJ/mol. K) on the interface between solid and liquid phases when the process was completed. The kinetic sorption data fitted best to the pseudo-second-order model (k2 = 2.79 × 10−2, 3.96 × 10−2, and 4.54 × 10−2 g/mg.min). The dried biosorbents of A0, A8, and A15, after modeling with the Langmuir and Dubinin–Radushkevich isotherm models, indicated that cadmium binding occurred through chemisorption (qmax, D-R = 9.74 × 10−4, 4.79 × 10−3, and 9.12 × 10−3 mol/g and mean free energy of 8.45, 11.18, and 11.18 kJ/mol) on the monolayer and homogenous surface (qmax, Langmuir of 12.24, 36.90, and 60.24 mg/g). In addition, the results of SEM, EDX, and FTIR showed that there were at least nine functional groups that interacted with Cd2+ (led to bond formation) after biosorption through cation exchange mechanisms, and morphologically the surfaces changed after biosorption. Biosorbent A15 indicated the best resilient features over three cycles of sorption–desorption using 1 M HCl as the desorbing eluent. These biosorbents can be a potent and eco-friendly material for treating aqueous wastewater.

Adsorption of tamoxifen on montmorillonite surface

Abstract The anticancerous drug tamoxifen is becoming a promising therapy, although some administration handicaps should be improved. Montmorillonite is a natural phyllosilicate and its use as carrier of the tamoxifen can be an interesting alternative for drug delivery system. Syntheses at different pH of montmorillonite-tamoxifen hybrids have shown promising possibilities. However, it is necessary to know the driving forces and intermolecular interactions responsible for tamoxifen adsorption on montmorillonite at different pH. Atomistic calculations of these systems have been applied based on empirical interatomic potentials. Theoretical simulations were used to explain the stoichiometry of the tamoxifen intercalation into the montmorillonite to understand the experimental behavior. The results showed there is influence on the clay structure when there is pH adjustment, with varying particle size, as well as variability in drug intercalation. Cationic species of tamoxifen was adsorbed by cation exchange mechanism and an additional adsorption of molecule as tamoxifen citrate pair also contributed in the interaction, being more energetically favorable.

Removal of calcium and magnesium from lithium concentrated solution by solvent extraction method using D2EHPA

In this work, a solvent extraction process for Ca2+ and Mg2+ removal from Li+ concentrated solution consisted of 30 g/L Li+, 1.5 g/L Ca2+ and 1.5 g/L Mg2+ was proposed, using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as extractant. The extraction process was a cation exchange mechanism, and the extraction sequence was Ca2+ > Mg2+ > Li+ > Na+. Under the optimum condition of 66% saponification degree, 3/2 phase ratio and three-stage extraction, the extraction efficiency of Ca2+, Mg2+ and Li+ reached 99.00%, 98.57% and 15.28%, respectively. The extracted cations could be completely stripped by HCl solution, and the co-extracted Li+ could be selectively stripped and separated from Ca2+ and Mg2+ using higher concentration HCl solution at higher phase ratio. A whole removal process for Ca2+ and Mg2+ involving extraction, scrubbing, stripping and saponification sections was put forward, and the process stability was continuously tested on centrifugal extractors. Removal efficiency of Ca2+ and Mg2+ reached 99.05% and 98.48% respectively. Meanwhile, the loss ratio of Li+ was as low as 5.22%.

Solvent extraction and molecular modeling studies of Dy(III) using acidic extractants

Abstract In the present work, solvent extraction of Dy(III) from chloride solutions using 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) and Cyanex 572 (a mixture of phosphonic and phosphinic acid extractants) diluted in kerosene has been reported. Pourbaix and speciation diagrams were plotted to understand the chemistry and formation of different species of Dy(III) in chloride solutions. The effects of different extraction parameters such as pH (1–5), extractant concentration (1–60 mM) and chloride concentration (0.05–1 M) were investigated. PC88A was found to extract Dy(III) ions better than Cyanex 572 under similar conditions. Experimental results showed that Dy(III) extraction reaction occurred via a cation exchange mechanism, which was further supported by Fourier-transform infrared spectroscopy (FTIR) studies of organic solutions loaded with Dy(III). Separation studies of Dy(III) from a mixed solution of 16 rare earth elements (REEs) indicate that PC88A works better for light REEs/Dy separation while selectivity of middle and heavy REEs over Dy(III) are superior with Cyanex 572. Molecular modeling was employed to calculate the Gibbs energies of Dy ions in aqueous and organic phases (consisting of phosphonic acid in heptane), which supported the experimental results.

Sorbent Materials Characterization Based on Mechanical or Thermal Pretreated Montmorillonite Modified by Surfactant Loading for Improved Chromium Retention

To improve hexavalent chromium (Cr(VI)) retention of montmorillonite (Mt) at pH 3, Mt sample was subjected to different treatments: thermal ones at 600 °C or 950 °C, 2 h, or mechanical grinding for 300 s. Then, the obtained products were loaded with different octadecyl trimethyl ammonium loading and 50% and 100% of Mt cation exchange capacity (CEC). The samples were characterized by several techniques at each stage. Differential thermogravimetric analysis (DTGA) performed on the products allowed determining the actual surfactant amount related to the internal or external surface by cation exchange and Van der Waals (VdW) mechanisms, respectively, taking into account the CEC of the thermal or mechanical pretreated Mt base sample used. X-ray diffraction (XRD) analyses revealed that the surfactant loading allowed the reversal of the collapsed interlayer after both treatments. The samples subjected to the thermal treatment at 600 °C and the raw Mt samples exhibit higher positive zeta potential values than the mechanical pretreated Mt ones with 100% of the CEC surfactant loaded at pH 3. This was directly related to the external surface covered by the surfactant. The agreement between the results of the surfactant coverage on the external surface and Cr(VI) removal at pH 3 indicates that the electrostatic mechanism is the main driving force for the sorption of Cr(VI). These synthesized sorbents achieve similar Cr(VI) retention using less than half the surfactant amount of already published studies.

A cost-effective process for recovering thorium and rare earths from radioactive residues

Ion-adsorbed rare earth ores radioactive residues (IREORR) are low-level radioactive wastes generated by the production processes of ion-adsorbed rare earth ores (IREO). IREORR were difficult to be managed due to their radioactivity and larger volume. The wastes have caused environmental concerns. In addition, IREORR were rich in rare earth elements (REEs). The contents of REEs in IREORR were much higher than those in IREO. In this study, a separation process based on 2-(4-(2,4,4-trimethylpentan-2-yl) phenoxy) acetic acid (POAA) for the recoveries of REEs and radioactive element Th from IREORR leachate have been developed. The extraction mechanism of POAA for Th was indicated to be cation exchange mechanism. Unsaponified POAA revealed a better selectivity for the separation of Th from mixed REEs. The separation of Th and enrichment of REEs from IREORR leachate were achieved by liquid-liquid extraction and extraction-precipitation, showing that this process may be cost-effective used to deal with IREORR leachate for environmental concerns and resource utilizations.

Selective Extraction of Light Lanthanides(III) by N,N-Di(2-ethylhexyl)-diglycolamic Acid: A Comparative Study with N,N-Dimethyl-diglycolamic Acid as a Chelator in Aqueous Solutions.

The complexation and selectivity of N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA/kerosene, HA) toward the light lanthanides, La(III), Ce(III), Pr(III), and Nd(III), are presented for the extraction from chloride media. In the low pH region (pH 1.8–2.8), the obtained data reveal that the extraction of Ln(III) is governed by cation-exchange mechanism and is driven by the negative change in enthalpy. The results from the slope analysis method suggest the formation of LnA3·(HA)1or2 in the extraction process. As major extracted species with a core of LnA3 in the first coordination sphere, LnA3 might connect with one or two additional HA molecules in the second coordination sphere by hydrogen bonding. The LnA3 core might share similar coordination geometry to those of 1:3 Ln(III) complexes (LnA′3) with water-soluble N,N-dimethyl-diglycolamic acid (HDMDGA, HA′) formed in aqueous solutions or in solid-state compounds. The correlation between the extraction with HDEHDGA (HA) as an extractant and the complexation with HDMDGA (HA′) as a chelator has been explored by interpreting the separation factors for HA with the difference in the stability constants for HA′. Consequently, the ratios of the stability constants of the corresponding 1:3 complexes (LnA′3) with HDMDGA could be reasonably translated to the separation factors (SFs) with HDEHDGA, providing a valuable approach for understanding the origin of the extraction/separation mechanism. By comparing the extraction selectivity of HDEHDGA with that of the currently deployed extractants in the industry such as P204, P507, and Cyanex 272, HDEHDGA offers outstanding selectivity with considerable SFs (SFCe/La = 6.68, SFPr/Ce = 2.79, and SFNd/Pr = 2.65) for light Ln(III) pairs under conditions of low acid concentrations.

Atomic layer deposition of cubic tin–calcium sulfide alloy films

Abstract