Phase Splitting Research Articles

Fluorous and Organic Extraction Systems: A Comparison from the Perspectives of Coordination Structures, Interfaces, and Bulk Extraction Phases.

Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency and selectivity. In this study, we correlated the macroscopic behavior of the Zr(IV) extraction from nitric acid solutions with microscopic structural information to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system as compared to the analogous organic extraction system. The fluorous and organic extraction systems consist of tris(4,4,5,5,6,6,7,7,7-nonafluoroheptyl) phosphate (TFP) in perfluorohexane and tri-n-heptyl phosphate (THP) in n-hexane, respectively. Extended X-ray absorption fine structure, neutron reflectometry (NR), and small-angle neutron scattering revealed the structural information around the central metal ion of the complex, at the interface, and in the bulk extraction phase, respectively. NR results showed that extractant molecules did not accumulate much at the interface in both extraction system. In the fluorous extraction system, extractant aggregates with a 1.46 nm radius of gyration (Rg) were formed after contact with nitric acid, and remained even after Zr(IV) extraction through the form of a 1:3 (Zr(IV):TFP) complex. In contrast, in the organic extraction system, only extractant dimers with Rg of 0.70 nm were formed and Zr(IV) is extracted through the form of a 1:2 (Zr(IV):THP) complex. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.

Tertiary amine based-biphasic solvent using ionic liquids as an activator to advance the energy-efficient CO2 capture

The newly developed tertiary amine-based biphasic solvents have low reaction heat, and good desorption performance, but no CO2 reactivity under low CO2 pressure. A novel tertiary amine-based biphasic solvent (DMEA/[DETAH]Lys/n-BuOH/H2O, abbreviated as D-DL-B-H) using ionic liquids (ILs) as the activator was proposed. With the assistance of [DETAH]Lys, the CO2-rich phase exhibited enhanced CO2 loading (from 3.69 to 4.09 mol/L) and CO2 distribution (from 88.5 % to 96.8 %). In addition, at 5 kPa, D-DL-B-H achieved an absorption capacity up to 1.58 mol/L, which was 79 times that of the DMEA/n-BuOH/H2O, suggesting the D-DL-B-H had good CO2 capture property at low CO2 pressure. At 393.15 K, the desorption efficiency of D-DL-B-H was as high as 80.9 %. In addition, the Qreg of D-DL-B-H was reduced to 1.78 GJ/t CO2, accounting for 44.61 % of the 30 wt% MEA. At 323.15 K, the viscosity of the CO2-rich phase was only 4.63 mPa·s, and the corrosion rate was 46.88 % of 30 wt% MEA. The reaction mechanism obtained from 13C NMR and DFT analysis indicated that [DETAH]Lys was more inclined to react with CO2 than DMEA. The main reason for the occurrence of phase splitting was the formation of hydrogen bonds between the CO2 product and the water.

Tuning the hydrophobicity-hydrophilicity: D,L-Menthol:Dodecanoic acid (2:1) in glycols – n-Hexane biphasic systems

Hydrophobic molecular eutectic solvents have been largely explored in the last decade especially due to the high tunability of their properties, according to the nature of their components and their proportions. Their use together with conventional solvents, such as water to develop hydrophobic-hydrophilic biphasic system is growing at a fast pace. This work explores the use of glycols to separate binary mixtures composed of two hydrophobic miscible components: a conventional solvent and neutral hydrophobic eutectic solvent (ES). For that purpose, D,L-menthol:dodecanoic acid (2:1), and n-hexane were used, adding low-molecular weight glycols, ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), and 200, 400 g/mol polyethylene glycol (PEG 200 and PEG 400 respectively) to promote phase splitting. As glycol molecular weight grows from EG to PEG 400, its hydrophobicity increases, and thus dodecanoic acid (C12) greatly changes its partition preferences, from n-hexane rich phase to an evener distribution between both phases, while D,L-menthol has the highest affinity for the hexane-rich phase. Finally, these two phases hydrophobic systems were used, as a proof of concept, in the separation of carotenoids from chlorophyll, where the easy tunability of the phases just by altering the ratio between the ES components is demonstrated, directing the components from one phase to the other.

ScS shear-wave splitting in the lowermost mantle: Practical challenges and new global measurements

Many regions of the Earth's mantle are seismically anisotropic, including portions of the lowermost mantle, which may indicate deformation due to convective flow. The splitting of ScS phases, which reflect once off the core-mantle boundary (CMB), is commonly measured to identify lowermost mantle anisotropy, although some challenges exist. Here, we use global wavefield simulations to evaluate commonly used approaches to inferring a lowermost mantle contribution to ScS splitting. We show that due to effects of the CMB reflection, only the epicentral distance range between 60° and 70° is appropriate for ScS splitting measurements. For this distance range, splitting is diagnostic of deep mantle anisotropy if no upper mantle anisotropy is present; however, if ScS is also split due to upper mantle anisotropy, the reliable diagnosis of deep mantle anisotropy is challenging. Moreover, even in the case of a homogeneously anisotropic deep mantle region sampled from a single azimuth by multiple ScS waves with different source polarizations (in absence of upper mantle anisotropy), different apparent fast directions are produced. We suggest that ScS splitting should only be measured at "null" stations and conduct such an analysis worldwide. Our results indicate that seismic anisotropy is globally widespread in the deep mantle.

Evidence for weak azimuthal anisotropy beneath the Kumaon-Garhwal Himalaya

SUMMARY This study attempts to interrogate the upper mantle deformation pattern beneath the Kumaon-Garhwal region, located in the western Himalaya, using shear wave splitting (SWS) analysis of core-refracted (XK(K)S) phases recorded at 53 broad-band stations. The fast polarization azimuths (FPAs) revealed by 338 well constrained measurements are dominantly clustered around ENE–WSW, with a few along the NE and E–W directions. The delay times vary from 0.2 to 1.4 s, with an average of 0.6 s that is smaller than that for the Indian shield (∼0.8 s), central and eastern Himalayas. The northern part of the lesser Himalaya shows a slightly smaller delay time compared to the southern part, which is attributed to the weakening of azimuthal anisotropy caused by the dipping of the Indian lithosphere. In order to understand the crustal contribution, its anisotropy is measured by analysing the splitting of Ps conversions from the Moho (Pms), akin to that of the XK(K)S phases. However, reliable results for crustal anisotropy could be obtained only at 10 stations. The average delay time due to crustal anisotropy is 0.47 s, with a variation from 0.2 to 0.9 s. Although the dominant period of Pms is smaller than that of SK(K)S, crustal anisotropy contributing to splitting of the latter phases cannot be ruled out. The orientation of FPAs obtained from Pms phases is found to be parallel or sub-parallel to those from XK(K)S phases, suggesting a similar deformation mechanism in the mid- to lower-crust and upper mantle. On the basis of FPAs derived from XK(K)S measurements, the Kumaon-Garhwal Himalaya (KGH) region can be divided into four subregions. In the western and eastern parts, the FPAs are mostly aligned along NE and ENE–WSW, and NE, respectively. In the central and south-eastern parts, their orientation is along ENE–WSW and NW, respectively. The strong ENE–WSW orientation in the central part could result from a slightly variable anisotropy in the crust to the upper part of the lithosphere or basal topography causing deflection of mantle flow. Also, the NW orientation in the south-eastern part of KGH is associated with a shallow source within the lithosphere. Application of the spatial coherency technique to single-layered anisotropic parameters results in a depth of 220–240 km, implying that the dominant source of anisotropy could lie in the upper mantle.

Local-S shear wave splitting along the length of the Alaska–Aleutian subduction zone

SUMMARY The Alaska–Aleutian subduction zone represents an ideal location to study dynamics within a mantle wedge. The subduction system spans several thousand kilometres, is characterized by a slab edge, and has ample seismicity. Additionally, the majority of islands along the arc house broad-band seismic instruments. We examine shear wave splitting of local-S phases originating along the length of the subduction zone. We have dense measurement spacing in two regions, the central Aleutians and beneath Alaska. Beneath Alaska, we observe a rotation in fast splitting directions near the edge of the subducting slab. Fast directions change from roughly trench perpendicular away from the slab edge to trench parallel near the boundary. This is indicative of toroidal flow around the edge of the subducting Alaska slab. In the central Aleutians, local-S splitting is primarily oriented parallel to, or oblique to, the strike of the trench. The local-S measurements, however, exhibit a depth dependence where deeper events show more consistently trench-parallel directions indicating prevalent trench-parallel mantle flow. Our local-S shear wave splitting results suggest trench-parallel orientation are likely present along much of the subduction zone excited by the slab edge, but that additional complexities exist along strike.

Integration of physical solution and ionic liquid toward efficient phase splitting for energy-saving CO2 capture

Carbon dioxide (CO2) capture from flue gas is crucial for achieving industrial carbon neutrality. Using a biphasic solvent can significantly reduce the volume of regenerated solvent for energy-saving carbon capture. In this study, a novel strategy for biphasic solvent preparation was proposed by combining amine blends (3,3′-Diaminodipropylamine, DADPA; N-Methyldiethanolamine, MDEA) and composite agents (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, BN; sulfolane, TMS). The screened proportion of DADPA:MDEA:TMS:BN:H2O was 2:6:2:1:2 (labelled DMTB). Experimental evaluation revealed that the DMTB solvent exhibits a high CO2 capacity of 4.59 mol/L (in the 50 vol% rich phase), an efficient phase splitting rate (within 3 min) and a fast CO2 desorption rate. The dynamic phase-splitting capacity was evaluated by a quasi-two-dimensional separator, under various operational condition. The 13C NMR results indicated the formation of DADPACOO- in the CO2-saturated phase in the presence of water rather than bicarbonate while observing dissociative behaviour in MDEA and TMS. Therefore, the phase separation analysis revealed that the products of protonated amines and carbamic acid species were highly polar and preferred to dissolve in the water phase. This study provides an optional biphasic solvent with phase splitting ability for CO2 capture from flue gas.

On the effects of a surrounding medium and phase split in coupled bone simulations

AbstractIn our previous contributions we established a multiscale, multiphase material model for the simulation of cancellous bone with the novel idea of including the full coupling of mechanical, electric and magnetic effects, which could be used for example, for the early detection of osteoporosis. While our calculations have already shown promising results, our previous approach lacks very important aspects, strongly limiting the applicability of our findings. In this paper we extend our base model by considering the effect of a surrounding medium on our bone specimen, using improved boundary conditions and differentiating between cortical bone, bone marrow and spongy bone to better reflect the physiological properties of bone. We show numerical results and compare our calculations to our previous modeling.

Capturing CO2 using novel nonaqueous biphasic solvent TMEDA/MEA/DMSO: Absorption and phase splitting mechanism

In order to ameliorate the issues of corrosion and high regeneration energy associated with traditional biphasic solvents, a nonaqueous biphasic solvent has been proposed as a potential alternative. This study introduces Tetramethylethylenediamine (TMEDA) as a phase splitter within the Ethanolamine (MEA)/Dimethyl sulfoxide (DMSO) system, resulting in a novel nonaqueous biphasic solvent, TMEDA/MEA/DMSO. Compared with other screened phase splitters, the appropriate polar size and intermolecular interaction force of TMEDA are the key factors that make it comply with the screening of nonaqueous biphasic solvent. When the mass ratio of TMEDA/MEA/DMSO is maintained at 3:3:4, the CO2 loading attains 0.54 mol (CO2)/mol (MEA), with the rich phase comprising 75 % of the total. 13C NMR and FT-IR characteristics showed that the absorbent product is mainly in the form of MEACOO−/MEAH+. Absorption and phase separation mechanisms of absorbent elucidated by DFT calculations and molecular dynamics simulations. The limited opportunity for TMEDA to interact with MEA molecules emerges as the primary reason for its reduced involvement in the reaction, with the inclusion of TMEDA intensifying the aggregation of MEACOO−/MEAH+ and triggering phase transition. In comparison to a 30 wt% MEA water-based absorbent, TMEDA/MEA/DMSO exhibits a 40 % reduction in regeneration energy (estimate) and possesses energy-saving attributes, rendering it a promising candidate for CO2 capture.

Solubilizer reconstructs the influences of the hydrogen-bond network of nonaqueous biphasic solvent on the absorption, phase splitting and desorption

Nonaqueous biphasic solvent has remarkable energy-saving potential. The weak force between N, N, N′, N″, N‴-pentamethyldiethylenetriamine (PMDETA) and Dimethyl sulfoxide (DMSO) contributes to facilitating the separation between DMSO and PMDETA, thereby enabling efficient liquid–liquid phase separation. Nevertheless, the weak interactions of PMDETA with other solvent molecules pose considerable challenges in the formulation of fresh homogeneous phase solutions. This study proposes a strategy to enhance PMDETA dissolution by introducing a solubilizer into a hybrid phase splitter, thereby increasing the concentration of PMDETA in the solvent. With the addition of a small quantity of solubilizer, the absorption, regeneration, and phase separation performance among the absorbents are comparable. The phase separation performance is influenced by the number of hydrogen bonds formed by the solubilizer, and the concentration of solubilizer in the lower phase is dependent on its hydrophobicity. Characterization using 13C NMR and FT-IR indicates that CO2 products primarily exist in the form of MEACOO−/MEAH+. Through DFT and molecular dynamics simulations, the impact of the solvent environment surrounding Ethanolamine (MEA) on the MEA+COO− deprotonation reaction is analyzed. While PMDETA offers a more favorable proton acceptance energy compared to MEA, the limited opportunities for PMDETA to come into contact with MEA molecules may be the primary hindrance to its participation in the reaction. Significantly lower corrosivity and regeneration energy requirements for non-aqueous biphasic solvents compared to 30 wt% MEA make them ideal candidates for energy-efficient, low-corrosivity CO2 capture.

Crustal and Uppermost Mantle Azimuthal Seismic Anisotropy of Antarctica From Ambient Noise Tomography

AbstractSeismic anisotropy provides essential information for characterizing the orientation of deformation and flow in the crust and mantle. The isotropic structure of the Antarctic crust and upper mantle has been determined by previous studies, but the azimuthal anisotropy structure has only been constrained by mantle core phase (SKS) splitting observations. This study determines the azimuthal anisotropic structure of the crust and mantle beneath the central and West Antarctica based on 8—55 s Rayleigh wave phase velocities from ambient noise cross‐correlation. An anisotropic Rayleigh wave phase velocity map was created using a ray—based tomography method. These data are inverted using a Bayesian Monte Carlo method to obtain an azimuthal anisotropy model with uncertainties. The azimuthal anisotropy structure in most of the study region can be fit by a two‐layer structure, with one layer at depths of 0–15 km in the shallow crust and the other layer in the uppermost mantle. The azimuthal anisotropic layer in the shallow crust of West Antarctica, where it coincides with strong positive radial anisotropy quantified by the previous study, shows a fast direction that is subparallel to the inferred extension direction of the West Antarctic Rift System. Fast directions of upper mantle azimuthal anisotropy generally align with teleseismic shear wave splitting fast directions, suggesting a thin lithosphere or similar lithosphere‐asthenosphere deformation. However, inconsistencies in this exist in Marie Byrd Land, indicating differing ancient deformation patterns in the shallow mantle lithosphere sampled by the surface waves and deformation in the deeper mantle and asthenosphere sampled more strongly by splitting measurements.

Model Predictive Control for Single-Stage Three- Phase Split Source Inverter With Enhanced Switched-Inductor Configuration

Model Predictive Control for Single-Stage Three- Phase Split Source Inverter With Enhanced Switched-Inductor Configuration

Synthesis, structural and luminescent properties of Lu2W3O12:Eu3+ concentration series

The lack of sufficient exploration of lutetium tungstate doped with europium ions has led to significant interest in terms of structure formation and luminescence properties. The series of (Lu1-xEux)2W3O12 powders (x = 0.01–1) was synthesized using an improved modified Pechini method (with additional gel treatment) and compared with the previously developed modified Pechini technique. The phase composition of the prepared samples was studied by X-Ray diffraction. XRD analysis verified the orthorhombic structure of the powders (for 1–50 at.% Eu3+) and the monoclinic structure (for 75 and 100 at.% Eu3+). The results also showed the occurrence of phase splitting and formation two Lu2W3O12 orthorhombic structures for Eu3+ concentrations above 40 at.% and two Eu2W3O12 monoclinic phases above 75 at.% Eu3+ without any impurities. Eu3+ doping concentration significantly affects the structural changes leading to different formations of the shape and size of the particles, the positions of the vibrational states, the luminescence characteristics, and the lifetime of the samples. The optimal doping concentration of Eu3+ is found to be 50 and 75 at.% for host and direct excitation, respectively. The observed 5D0 lifetime gradually decreases from 0.47 ms to 0.1 ms with the growth of the Eu3+ ions number.

Research of novel polyamine-based biphasic absorbents for CO2 capture using alkanolamine to regulate the viscosity and mechanism analysis

Biphasic solvent has attracted widespread attention in CO2 chemical absorption technology due to its significant potential for reducing capture energy consumption. However, the high viscosity of CO2-rich phase after phase split could lead to issues such as high flow resistance, low heat transfer efficiency, and phase separation instability in application. To address these limitations, a strategy of using alkanolamine as a viscosity regulator for biphasic solvents was proposed. Diethanolamine(DEA), an alkanolamine regulator, was introduced to a system of polyamine/amide absorbent, and then a novel biphasic solvent of diethylenetriamine (DETA)/diethanolamine(DEA)/N, N-Dimethylacetamide(DMAC)/water(H2O) was developed. The viscosity of the CO2-rich phase solvent was reduced to 19.02 mPa⋅s, a significant decrease compared to the solution without DEA regulation. The novel solvent exhibited a high cyclic capacity of 2.08 mol/kg, which was 43.4 % higher than that of the solution without DEA, and a desorption rate twice as high as 30 wt% monoethanolamine(MEA). Quantitative 13C Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD) simulations revealed the phase split and viscosity regulation mechanisms. It was proved that DETA species, especially carbamates, tend to self-aggregate with each other due to intermolecular hydrogen bonding with the CO2 loading increases, which leads to phase split and high viscosity of the saturated solution. Through DEA regulation, the protonation of carbamates and the generation of HCO3–/CO32– were promoted, which weakened the self-aggregation of carbamates species, decreasing the viscosity and the regeneration energy of saturated CO2-rich phase solution. The regeneration energy reached 2.19 GJ/ton CO2, which exhibited a 42.4 % reduction compared with that of 30 wt% MEA.

The phase behavior of Isopropanol/Water/NaCl mixtures at atmospheric pressure and temperatures from 294.15 K up to the boiling point

Branched-chain higher alcohols (BCHAs) have potential applications in the preparation of biofuels as they have properties similar to those of gasoline. Isopropanol is the simplest member of the BCHA family and is produced by either a catalytic process or fermentation of biomass. Regardless of the process, the isopropanol is produced as a component of a mixture with water content as high as 80%; therefore, purification is needed to produce fuel-grade isopropanol. Azeotropic and heteroazeotropic distillation are currently used to purify the isopropanol but they are carbon-intensive and costly. The addition of NaCl to an isopropanol/water mixture has two effects: could trigger a liquid–liquid phase split; and increases the relative volatility of the alcohol. These effects could potentially be used as the departure for the design of low-carbon and less expensive purification operations.The phase behavior of isopropanol/water/NaCl mixtures was experimentally mapped at temperatures up to the boiling point at atmospheric pressure. The liquid–solid, liquid–liquid, liquid–liquid–solid, liquid–vapor, liquid–liquid–vapor, liquid–liquid–solid–vapor and liquid–solid–vapor regions were experimentally detected and located in the phase diagram. The equilibrium compositions within the liquid–liquid, liquid–vapor and liquid–liquid–solid–vapor regions were measured. Three well-known methods were employed to assess the reliability of the measured liquid–liquid phase compositions. The temperatures and the composition of the vapor phase in the liquid–liquid–vapor region were also experimentally measured. The collected experimental data was used to construct the phase diagram of isopropanol/water/NaCl mixtures at 5, 10 and 20 wt% NaCl content, at atmospheric pressure, and temperatures from 294.15 K to the boiling point.

Phase split of gas–non‐Newtonian fluid two‐phase flow in a ψ‐shaped branching microchannel

AbstractAn experiment of phase split was conducted in a horizontal ψ‐shaped branching microchannel to study the phase distribution and pressure drop at the bifurcation. The pressure drop at the test section and the flow rates of the gas and liquid phases through the three branches were measured. The pressure drop gradients at the inlet and branches were predicted by the correlation based on the separated flow model. The critical condition for the split of the two‐phase flow was determined. The results showed that the gas phase separated from the side arm was more than the liquid phase. A uniform distribution could be achieved for the churn flow in water. Pressure drop occurred at the bifurcation of the side arm under the effect of the vortex in the liquid slug near the bubble nose; the pressure drop was much greater than that at the bifurcation of the run.

Boosting CO2 absorption and desorption of biphasic solvent by nanoparticles for efficient carbon dioxide capture

Introduction of nanoparticles (NPs) in the solvent was treated an efficient route to enhance mass and heat transfer, therefore, it was a promising strategy to boost carbon dioxide (CO2) absorption and desorption, especially for the biphasic solvent with weak absorption rate and low heat capacity. Herein, powder TiO2 and SiO2 with nanoscale was selected to prepare nanofluid for CO2 capture, based on DMPA-NHD biphasic solvent. The stability of nanofluid and the effect of NPs on CO2 absorption–desorption, phase-splitting was comprehensively explored in this work. Experimental results revealed that 0.06 wt% dosage of 30 nm TiO2 presented excellent performance for CO2 absorption. The liquid film resistance decreased by 11.8% after introducing NPs, therefore, the maximum mass transfer coefficient was 1.88 × 10-10 mol·cm−2·s−1·Pa (at 30 °C), increasing by 30% than the blank. In addition, 0.06 wt% dosage of 50 nm SiO2 leaded to significant promotion for CO2 desorption, with the maximum desorption rate at 3.9 mmol/min, and the desorption energy consumption reduced by 9.5% compared with blank case. Importantly, introduction of NPs had no significant effect on the phase splitting behavior, according to the time-profile phase-splitting measurements. The advantage influence of NPs was well validated by current DEEA-AEEA and MEA-sulfolane biphasic solvent. Furthermore, the bench-scale CO2 absorption and desorption evaluation revealed that the relative energy consumption was respectively reduced by 15.9% and 10.0%, after introduction of 50-Si-NPs and 30-Ti-NPs.

Proper and improper ferroelastics with perovskite-derived structures

Based on the combined group-theoretical and crystallographic approach, the possible perovskite-derived structures of proper and improper ferroelastics were established. The crystallographic analysis of the Wyckoff position splitting in the low-symmetry proper ferroelastic phases shows the absence of any non-ferroelastic degrees of freedom that reduces the possibilities of structural relaxation. Group-theoretical analysis reveals that tilts of anionic octahedra, as the most common type of structural distortions in perovskites, are closely related to ferroelastic strains, except for the phase with tilt pattern a + a + a +. For such kind of improper ferroelastics, the simplest classification was suggested based on the relationships between the coupled order parameter (tilts of octahedra) and the lattice strain components.

Effect of alcohols on CO2 absorption, phase splitting, and desorption behaviors of biphasic anhydrous system: The primary amine-tertiary amine of DGA-PMDETA

Chemical absorption with organic amine solution is the most mature technology for CO2 capture. Some biphasic anhydrous absorbents show potential in reducing regeneration energy consumption, but high viscosity of the CO2 rich phase hinders its practical application. Alcohols are commonly employed as dilutes to reduce viscosity reducers, while its effect on CO2 absorption and phase splitting behaviors are still unclear. In this study, the effects of alcohols on CO2 absorption and phase-splitting of biphasic anhydrous 2-(2-Aminoethoxy)ethanol (DGA) -N,N,N′,N″,N″-pentamethyl diethylenetriamine (PMDETA) -alcohol systems are investigates. Adding alcohol reduces the viscosity of the CO2-rich phase, enhances desorption rate, and decreases the phase splitting time. The rich phase entrainment stage and the rich phase thickening stage, can be distinguished along with during CO2 absorption. The majority DGA reacts with CO2 in the rich phase since the phase splitting begins. This work may provide some basis for further biphasic absorbent design and regulation.

The phase split forced by salts or carbohydrates in nonaqueous systems

More than 2500 ternary systems containing binary nonaqueous solvents and a salt or carbohydrate were checked experimentally under ambient conditions to demonstrate the liquid–liquid phase split. The binary solvents consisted of one strongly polar component and another significantly less polar. Phase separation has been observed in more than 300 systems. These systems are direct analogues of the aqueous two-phase systems (ATPS) that have been extensively studied and found numerous applications. The obtained data were analyzed and some correlations were observed. Possibilities of creating the liquid–liquid miscibility gap depending on the solvents’ polarity and the solute properties were discussed. This phenomenon most often occurs with binary solvents containing a strongly polar component, such as formamide, dimethyl sulfoxide, ethane-1,2-diol, or N-methylformamide. Carbohydrates have been found to be better liquid–liquid phase split inducers than salts. Among the latter, calcium and lithium chlorides, and sodium iodide turned out to be the most effective. A strict correspondence of the decreasing probability of creating a miscibility gap by different ions with the reversed Hofmeister series was confirmed.