Water-organic Mixtures Research Articles

Mathematical modeling of stationary thermopervaporation through hydrophobic membrane

The paper proposes a one-dimensional mathematical model of stationary thermopervaporation of water-organic mixture through a non-porous hydrophobic membrane. The driving force of the process is the difference in the temperature and concentration of the mixture components on both sides of the membrane. The model takes into account the difference in interaction between molecules of the liquid and vapor phases of the mixture components with the membrane matrix (equilibrium distribution coefficients), as well as the difference in the diffusion coefficients of the components in all areas. The problem of heat transfer is solved independently. The temperature distribution in layers of the membrane system (diffusion boundary layer, membrane and permeate) is determined. It is assumed that the evaporation front coincides with the working side of the membrane. In the general case, the boundary value problem is solved numerically by the shooting method. As a result, the distribution of the mass fraction of the organic component over the membrane cell is obtained. The dependences of the separation factor and the pervaporation separation index (PSI) on the main parameters of the problem are determined. It is demonstrated that the dependence of the PSI on the separation factor has extremal character. This allows to select optimal conditions for thermopervaporation for the given parameters of the membrane system. In the limiting case when the fluxes of the mixture components are equal to zero, the solution is obtained analytically. The maximum possible separation factor can be determined using an analytical solution. The present model was successfully verified using the literature experimental data on the thermopervaporation separation of butanol and ethanol aqueous solutions through the membranes of various types.

Comparison of Classical and Green RPLC Methods in the Determination of pKa Values of Some Piperazine Group Antihistamines.

In this study, protonation constant values and liquid chromatographic behaviors of hydrophobic cyclizine, chlorcyclizine, hydroxyzine, cinnarizine, cetirizine, meclizine, and buclizine in some water-organic solvent binary mixtures were examined for the first time using classical and green reverse phase liquid chromatography methods. In the isocratic study, the relationship of the retention time and mobile phase pH in water-organic solvent binary mixtures containing acetonitrile (45, 50, 55, 60, 65%, v/v), methanol (60, 65, 70, 75%, v/v) and ethanol (45, 50, 55, 56, 59, 60, 62, 65%, v/v) were determined at 37 °C. In the study, XBridge C18 and Gemini NX C18 columns suitable for the chemical properties of basic compounds were used. The obtained liquid chromatographic data were analyzed using the linear solvation energy relationship methodology and the SOLVER program. The aqueous protonation constant values of the investigated compounds were calculated using the linear relationship between the protonation constant data calculated in studied binary mixtures and some macroscopic constant values of the solvents used. The greenness of methods developed using three different solvents was evaluated with the Analytical Greenness Metric Approach, the Green Analytical Procedures Index, and the Green Solvent Selection Tool approaches.

Enhanced Nanoparticle Sensing in a Highly Viscous Nanopore.

Slowing down translocation dynamics is a crucial challenge in nanopore sensing of small molecules and particles. Here, it is reported on nanoparticle motion-mediated local viscosity enhancement of water-organic mixtures in a nanofluidic channel that enables slow translocation speed, enhanced capture efficiency, and improved signal-to-noise ratio by transmembrane voltage control. It is found that higher detection rates of nanoparticles under larger electrophoretic voltage in the highly viscous solvents. Meanwhile, the strongly pulled particles distort the liquid in the pore at high shear rates over 103 s-1 which leads to a counterintuitive phenomenon of slower translocation speed under higher voltage via the induced dilatant viscosity behavior. This mechanism is demonstrated as feasible with a variety of organic molecules, including glycerol, xanthan gum, and polyethylene glycol. The present findings can be useful in resistive pulse analyses of nanoscale objects such as viruses and proteins by allowing a simple and effective way for translocation slowdown, improved detection throughput, and enhanced signal-to-noise ratio.

Zr-Based MOF-Stabilized CO2-Responsive Pickering Emulsions for Efficient Reduction of Nitroarenes.

A Pickering emulsion is a natural microreactor for interfacial catalysis in which an emulsifier is critical. Recently, a metal-organic framework (MOF) has attracted attention to emulsify water-organic mixtures for constructing a Pickering emulsion. However, a few stimuli-responsive Pickering emulsions based on MOFs have been reported, and the MOF emulsifiers cannot be regenerated at room temperature. Herein, the Zr-MOF with a rodlike morphology is synthesized using ionic liquid as a modulator and then modified with n-(trimethoxysilylpropyl)imidazole (C3im) to prepare a series of functionalized Zr-MOFs (MOF-C3im). It is found that MOF-C3im is an excellent emulsifier to construct stable and CO2-responsive Pickering emulsions even at low content (>0.20 wt %). Notably, the emulsification and demulsification of the emulsions can be easily and reversibly switched by bubbling of CO2 and N2 alternatively at room temperature because CO2 and imidazole molecules anchored on the Zr-MOF underwent a reversible acid-base reaction, resulting in an obvious change in the wettability of the emulsifier. As a proof of concept, the reduction reactions of nitrobenzene have been successfully carried out in these Pickering emulsions, demonstrating the efficient integration as a microreactor for chemical reaction, product separation, and emulsifier recycling under ambient conditions. This strategy provides an innovative option to develop stimulus-responsive Pickering emulsions for sustainable chemical processes.

Supramolecular Large Nanosheets Assembled at Air/Water Interfaces and in Solution from Amphiphilic Heptagon-Containing Nanographenes.

We report the synthesis of a new set of amphiphilic saddle-shaped heptagon-containing polycyclic aromatic hydrocarbons (PAHs) functionalized with tetraethylene glycol chains and their self-assembly into large two-dimensional (2D) polymers. An in-depth analysis of the self-assembly mechanism at the air/water interface has been carried out, and the proposed arrangement models are in good agreement with the molecular dynamics simulations. Quite remarkably, the number and disposition of the tetraethylene glycol chains significantly influence the disposition of the PAHs at the interface and conditionate their packing under pressure. For the three compounds studied, we observed three different behaviors in which the aromatic core is parallel, perpendicular, and tilted with respect to the water surface. We also show that these curved PAHs are able to self-assemble in solution into remarkably large sheets of up to 150 μm2. These results show the relationship, within a family of curved nanographenes, between the monomer configuration and their self-assembly capacity in air/water interfaces and organic-water mixtures.

Electrochemical Sensing of Vitamin D3: A Comparative Use of Glassy Carbon and Unmodified Screen-Printed Carbon Electrodes

This work presents the electrochemical determination of cholecalciferol (Vitamin D3) in water-organic mixtures using a glassy carbon electrode (GCE) and commercial screen-printed carbon electrodes (SPCEs). The electrocatalytic behavior of Vitamin D3 on the surface of the working electrode produced a well-defined oxidation peak at +0.95 V (vs. Ag|AgCl, 3.0 mol L−1) and +0.7 V (vs. Ag-SPCE pseudo-reference electrode) for the GCE and SPCE, respectively, in 0.1 M LiClO4 prepared in 50% ethanol. The nature of the organic solvent needed for the solubilization of Vitamin D3 was evaluated, together with the concentration of the supporting electrolyte, the ratio of the water-organic mixture, the voltametric parameters for the cyclic voltammetry (CV), and square-wave voltammetry (SWV) analyses. Under the optimized conditions, a linear correlation between the anodic peak current and the concentration of Vitamin D3 was obtained over the range of 0.47 to 123 µmol L−1 and 59.4 to 1651 µmol L−1 for the GCE and SPCE, respectively. The determined limits of detection (LOD) were 0.17 (GCE) and 19.4 µmol L−1 (SPCE). The methodology was successfully applied to commercial supplement tablets of Vitamin D3. Additionally, this work shows the possibility of using non-modified GCE and SPCE for routine analysis of Vitamin D3.

Novel Siloxane Derivatives as Membrane Precursors for Lactate Oxidase Immobilization.

We report new enzyme-containing siloxane membranes for biosensor elaboration. Lactate oxidase immobilization from water-organic mixtures with a high concentration of organic solvent (90%) leads to advanced lactate biosensors. The use of the new alkoxysilane monomers-(3-aminopropyl)trimethoxysilane (APTMS) and trimethoxy[3-(methylamino)propyl]silane (MAPS)-as the base for enzyme-containing membrane construction resulted in a biosensor with up to a two times higher sensitivity (0.5 A·M-1·cm-2) compared to the biosensor based on (3-aminopropyl)triethoxysilane (APTES) we reported previously. The validity of the elaborated lactate biosensor for blood serum analysis was shown using standard human serum samples. The developed lactate biosensors were validated through analysis of human blood serum.

Bio-aerogels derived from corn stalk and Premna Microphylla leaves as eco-friendly sorbents for oily water treatment: The role of microstructure in adsorption performance

Internal microstructure significantly affects the physicochemical properties and the adsorption ability of bio-aerogels. The effect of microstructure structure of bio-aerogels on oil sorption is still remain unexplored, thus needs a systematic and comparative study. In this study, cellulose nanofibers (CNF) derived from corn stalk were blended with Premna Microphylla leaves (PML) to fabricate bio-aerogels with distinct internal microstructure via two freeze casting methods, unidirectional and random freezing, aiming to shed lights on the correlation between capillary structure and oil sorption mechanism. At an optimized CNF/PML mass ratio of 9, the silanized CNF/PML bio-aerogels synthesized via random (SC9/P1R) and unidirectional freeze-drying (SC9/P1U) exhibited unorderly porous structure and parallel capillary structure, respectively. The blending of pectin-rich PML with CNF at an appropriate amount enhanced the crosslinking and reduced the bulk density and pore wall density of bio-aerogels, thereby enhancing the oil adsorption ability. Unorder-microstructure bio-aerogels were superior to order-microstructure ones in terms of oil sorption performance. The maximum machine oil sorption capacity for SC9/P1R and SC9/P1U was 130.1 and 97.5 g/g, respectively. Efficient separation of the oil and organic solvents from the organic-water mixture was achieved by SC9/P1R because of its high hydrophobicity and olephilicity. Besides, SC9/P1R can be reused for at least 15 cycles, showing prominent recovery potential. Unlike most other research, this works provides a proof of the superiority of random microstructure bio-aerogels over the finely-tuned capillary-structured ones for selective oil sorption. Therefore, under some circumstances, the isotropic bio-aerogels may be more effective than the anisotropic ones in applications to oil pollution treatment.

Effect of the interaction between wood constituents and swelling liquid on the creep properties of wood during drying

Abstract This study aimed to clarify the effect of the interactions between the swelling liquid and wood constituents on the creep behavior during drying. Creep tests were conducted during drying of four sample groups (untreated, acetylated, delignified, and hemicellulose-extracted samples) that were swollen using water, one organic liquid, or water-organic mixtures. The largest creep deformation was measured for the hemicellulose-extracted samples, followed by delignified, untreated, and acetylated samples. Apart from the acetylated samples, all treated samples tended to have large creep deformation in water-organic mixtures. For the acetylated samples, the creep deformation was small, except in case of acetone. These differences in the creep deformation behavior are mainly due to the differences in the glass-transition temperature of lignin as a result of the interaction between the wood constituents and the swelling liquid. The considerable increase in creep deformation due to hemicellulose-extraction suggests that hemicellulose, which interacts with lignin and cellulose, reduces the fluidity of the wood due to liquid desorption during creep measurements.

Features of l-Tryptophan Solvation in Some Water–Organic Mixtures at T = 298.15 K

The effect of changes in the composition of some water–organic mixtures on the thermodynamic parameters of dissolution and solvation of l-tryptophan was studied by the method of calorimetry of dissolution at T = 298.15 K. To explain the experimental results, the enthalpic coefficients of pairwise interactions between l-tryptophan and organic cosolvent molecules and the energy contributions of the side chain to the energy of intermolecular interactions are calculated, and the influence of some properties of organic solvents on these interactions is estimated. All the data obtained were compared with those for l-phenylalanine to reveal the influence of the side chain structure on the energy of intermolecular interactions of aromatic amino acids with organic solvent molecules in aqueous solutions.

Zwitterion-neutral form equilibria and binding selectivity of pyridineboronic acids.

A 11B NMR study of 3-pyridineboronic acid at variable pH in water and 50 vol% aqueous dioxane confirms that the tautomeric equilibrium of the acid is shifted to the zwitterionic form in water, but to the molecular form in the mixed organic solvent. Interactions of 3- and 4-pyridineboronic acids with sialic acid, fructose and several other diols were studied by potentiometric titrations in a wide range of pH in water and water-organic mixtures. In all reaction media the stability of boronate complexes increases upon an increase in pH for neutral low acidic diols such as fructose and glucose but has the opposite trend for highly acidic sialic and lactic acids occurring as anionic species. The selectivity of pyridineboronic acids to sialate anions in an acidic medium is interpreted quantitatively by combining the pH-profiles with Brønsted type correlations for binding constants. In addition, mathematical expressions allowing one to predict the optimum pKa value of a boronic acid for the strongest binding of a given diol (sialic acid or fructose) at a given pH are suggested. The shifts in the tautomeric equilibrium induced by changing the solvent polarity in aqueous-organic mixtures are manifested in the magnitude of relative shifts of pKa of pyridineboronic acids induced by diol complexation.

Carbon nanotube enhanced membrane filtration for trace level dewatering of hydrocarbons

A highly hydrophobic membrane prepared by immobilizing carbon nanotubes (CNTs) over PTFE microfiltration membrane is presented for the dewatering of organic-water mixtures containing trace amounts of water. The effects of different CNT concentrations on membrane morphology, wettability, hydrophobicity, porosity, and permeability were characterized. After immobilization of CNT into membranes, the contact angle increased by 9% and 16% compared to unmodified 0.1 μm and 0.22 μm pore sizes membranes respectively. The carbon nanotube immobilized membrane (CNIM) showed remarkable separation efficiency for octane and heptane water systems. The enhanced hydrophobicity of the CNIM helped nano/micro water droplets to coalesce on the CNT present on the membrane surface which led to their rejection. In general, the water rejection increased, and the solvent flux decreased with CNT incorporations. For the octane water system, CNIMs were fabricated with 0.1 and 0.22 μm pore sizes, at the optimized CNT loading of 3 and 6 wt%, the water rejection was 99.87% and 97.60% respectively while the fluxes were 44.947 kg/m2.hr and 54.66 kg/m2.hr for octane water system. Water rejection for CNIM with 0.1 μm pore size was 99.87% and 99.98% respectively for octane-water and heptane-water systems, which were 20.3% and 20.5% higher compared to one without the CNT coatings.

Co-transport of water and p-xylene through carbon molecular sieve membranes

Carbon molecular sieve (CMS) materials are a potential candidate for scalable and high-performance reverse osmosis membranes due to their impressive chemical and thermal stabilities. Moreover, they have the potential to enable impressive rejections of small neutral solutes from water based on their known ability to separate small organic molecules. CMS has been extensively examined for gas and organic solvent separations, but the transport of organic and aqueous mixtures through CMS microstructures is poorly understood. In this work, we investigated the sorption, diffusion, and permeation behavior of organic compounds and water in poly(vinylidene fluoride)(PVDF)-derived CMS (PVDF-CMS). Experimental observations of diffusion, sorption, and permeation shows how the properties of penetrants such as polarity and molecular size affect the transport rates and selectivity. These basic transport and sorption parameters are utilized in sorption-diffusion models to permeation rates of water-organic mixtures in CMS membranes. The transport of water and p-xylene in CMS was experimentally confirmed to follow the sorption-diffusion mechanism. The sorption-diffusion model ideal permselectivity indicates that the CMS is p-xylene selective over water. Water/p-xylene mixture permeation experiments revealed an increased selectivity of p-xylene over water, thus providing tentative evidence for a competitive sorption-selective separation mechanism. This work suggests that CMS membranes exhibit organic-permeable separation properties in water/organic separations. The results presented here highlight the potential for the removal of dilute organics in water via CMS pervaporation membranes.

Measurement of Water Activity in the Presence of High Volatile Concentrations Using a Tunable Diode Laser-Single Laboratory Validation, First Action 2021.04.

Water activity is measured by equilibrating a test portion with a sealed head space and measuring the test portion temperature and the vapor density of the head space. The water activity is the ratio of head space vapor density to the saturation vapor density at test portion temperature. Headspace vapor density is typically measured using capacitance or chilled mirror sensors, but, when volatiles in significant concentration are present, these measurements may fail. Evaluate the accuracy of a tunable diode laser (TDL) for measuring the headspace vapor density and water activity of pharmaceutical preparations and food in the presence of non-aqueous volatiles. A commercial TDL water activity meter was calibrated against standards of known water activity and used to measure water activity of pharmaceutical preparations and food with high concentrations of non-aqueous volatiles. When no volatiles other than water vapor are present, this method is capable of measuring water activity with an accuracy of 0.005 or better. When high concentrations of volatiles such as ethanol, isopropanol, propylene glycol, tetrahydrofuran, or acetonitrile are present the uncertainty of the measurement increases. This is at least partly due to the uncertainty of the standards. Based on uncertainties in the water activity estimates of the water-organic mixtures, the uncertainties in water activity measurements with high concentrations of non-aqueous solvents is 0.02 or less up to mass fractions of the organic of 0.97. The theoretical background for TDL measurement of water activity is presented showing that the water vapor concentration is proportional to the area of the absorption line which is not affected by the presence of other volatiles.

Sorption Behaviour of Inorganic Material Filled-PDMS Films in Ethanol, Butanol, Acetone and Water

The pervaporation method in which the transport mechanism through a nonporous membrane is explained by the solution-diffusion model can be used for the separation of water-organic and organic-organic mixtures. The sorption behaviour of a polymeric membrane plays important role in membrane transport, depending on the solvent and polymer properties. Since the membrane itself is the key component in the pervaporation method, as with all other membrane processes, it is necessary to determine suitable membrane material that can selectively separate at least one component from a liquid mixture. Ethanol, butanol and acetone are widely used in many industrial applications. PDMS is one of the polymers that is frequently used in the recovery of organics from organic-water mixtures or the separation of organic-organic mixtures. PDMS gives high chain mobility, low mechanical resistance and low selectivity values. For this reason, its properties need to be improved. In this study, unfilled PDMS, PDMS/TiO2, PDMS/NaY and PDMS/5A mixed matrix films were prepared, and the sorption behaviours of prepared PDMS films in different chemical substances at temperatures of 30,40 and 50°C were investigated.

Fabrication of low cost and high performance NaA zeolite membranes on 100-cm-long coarse macroporous supports for pervaporation dehydration of dimethoxymethane

• High performance NaA zeolite membrane was prepared on 100-cm-long coarse macroporous supports. • A simple sandpaper polishing method effectively improved membrane separation selectivity. • These membranes exhibited a superior long-term stability for a 96 wt% DMM/H 2 O mixture. • The permeation flux was almost recovered using a 15 wt% H 2 O/MeOH PV test cleaning method for 4 h. Low cost and high performance NaA zeolite membranes have been successfully prepared on 100-cm-long coarse macroporous alumina supports using industrial grade reagents and chemicals. A simple and efficient sandpaper polishing method can effectively reduce the support surface roughness and the formation process of NaA zeolite membranes was investigated on inexpensive coarse supports by secondary growth, which was more conducive to the preparation of high performance membranes. For separation of a 90 wt% EtOH/H 2 O mixture at 348 K, the scaled-up NaA zeolite membrane showed a permeation flux of 4.67 kg m −2 h −1 and a high separation factor of more than 10,000. Simultaneously, these membranes were used for pervaporation (PV) dehydration of a dimethoxymethane/water (DMM/H 2 O) mixture for the first time, which exhibited a permeation flux of 0.89 kg m −2 h −1 and together with a separation factor of more than 23,000 at 313 K for dehydration of a 96 wt% DMM/H 2 O mixture. Moreover, the membrane also showed a superior long-term stability for running over 10 d. Importantly, the study on the recovery of permeation flux of scaled-up NaA zeolite membranes after long-term PV experiment to produce high-concentration DMM product (water content was less than 0.1%) found that the permeation flux was recovered to more than 85% of the fresh membranes after the membranes was cleaned using PV test with a methanol aqueous solution. These 100-cm-long NaA zeolite membranes with low cost and high performance demonstrated a promising industrial application prospects for PV dehydration of DMM/H 2 O mixtures and other organic water mixtures.

Vapor‐phase polymerization of high‐performance thin‐film composite membranes for nanofiltration

AbstractThin‐film composite (TFC) membranes are commendable semipermeable barriers for water treatment. Although conventionally immiscible interfaces between aqueous and organic solutions are widely utilized for obtaining TFC membranes, interfacial polymerization still suffers from the issues of harmful solvents, complex diffusion/reaction of the reactants, and thermodynamic and kinetic instability of interfaces. In this study, vapor‐phase polymerization with no requirements for organic solvent and immiscible interface is utilized for processing TFC nanofiltration membranes. Through cross‐linking ofβ‐cyclodextrin and piperazine layers by trimesoyl chloride vapor, polyester and polyamide TFC membranes with high cross‐linking degree are simply prepared in a scalable and reproducible manner. The prepared TFC membranes exhibit stable nanofiltration and desalination performance for all water, organic solvent, and water–organic mixture systems, with permeance up to an order of magnitude higher than that of commercial membranes.

Experimental and computational kinetics study of the liquid-phase hydrogenation of C[dbnd]C and C[dbnd]O bonds

Solvent effects on adsorption equilibrium and reaction kinetics are evaluated for hydrogenation reactions catalyzed by Pd/alumina in a series of different solvents. Three reactants – cyclohexene, benzene and benzaldehyde – and three solvents – n-heptane (HEP), methylcyclohexane (MCHA), decalin (DL) – have been investigated. Kinetic analysis of hydrogenation of cyclohexene reveals that hydrogen adsorbs on different sites from those where cyclohexene and the solvents adsorb; however, the presence of hydrogen on these separate sites affects the heats of adsorption of the hydrocarbons. When the solvent is a weakly interacting linear alkane (HEP), the rate determining step of the reaction is the first hydrogenation of adsorbed cyclohexene. This conclusion is supported by DFT calculations that show a higher enthalpy barrier for the first hydrogenation than for the second, while statistical thermodynamics analysis validates the physical significance of the entropy of adsorption parameters derived from the kinetic fitting of experimental data. By contrast, with solvents such as MCHA and DL, which interact more strongly with the metal surface and compete for active sites with the reactant and the surface intermediate, the rate limiting step seems to shift to the second hydrogenation step.One of the main conclusions of the study is that the effects observed with non-polar solvents are mostly due to competitive adsorption of the solvent, which causes a decrease in surface coverage of reactants and surface intermediates. Indeed, under identical conditions, the hydrogenation rates of CC bonds in cyclohexene (or the aromatic ring in benzene) follow the order HEP > MCHA > DL, which is consistent with the strongest solvent/metal interaction for DL and the weakest for HEP. Further, binary solvent mixtures of DL-HEP exhibit non-idealities that are clearly evident in the fitting of hydrogenation rates. It is proposed that the higher activity coefficient of liquid DL in the liquid mixture enhances its surface coverage, competing more effectively with the reactant, which causes a decrease in catalytic activity larger than that predicted assuming an ideal mixture of solvents.Likewise, large drops in benzene hydrogenation rates are observed in water-organic co-solvent mixtures due to the competitive adsorption of water on the Pd surface. Water adsorption is further enhanced by the non-ideality of the water-organic mixture. By contrast, in the hydrogenation of the CO bond of benzaldehyde, the presence of water provides a favorable alternative reaction path with lower activation barrier, resulting in higher hydrogenation activity when the reactant is a carbonyl-containing molecule, such as benzaldehyde. In this system, the H-bonded water network assists shuttling a proton from the Pd surface to the hydrophilic O atom in CO, assisted by surface charge separation. Since this H transfer pathway cannot take place with CC bonds or aromatic rings, only site inhibition occurs for these reactions.

Фазовые равновесия и высаливание 2-(2-бутоксиэтокси)этанола в тройной системе нитрат калия–вода–2-(2-бутоксиэтокси)этанол

Visual polythermal method in the bynary system of water-2-(2-butoxyethoxy) ethanol in the range of –25÷0° C the ice melting line is determined and the phase equilibria in the ternary system potassium nitrate–water–2-(2-butoxyethoxy) ethanol are studied in the range of 10.0–90.0° C. The ice melting line in the water–2-(2-butoxyethoxy) ethanol binary system is a flat, smooth line. This form of the melting line shows a hidden separation in liquid mixtures. It has been found that potassium nitrate salts out 2-(2-butoxyethoxy)ethanol from water-organic mixtures, and at 31.7° C in the ternary system of potassium nitrate–water–2-(2-butoxyethoxy)ethanol, separation begins. The compositions of the solutions corresponding to the critical solubility points at several temperatures have been determined. The isothermal phase diagrams of the ternary system at 10.0, 25.0, 30.0, 31.7, 35.0, 50.0, 90.0° С have been plotted. The distribution coefficients of 2-(2-butoxyethoxy) ethanol between the liquid phases of monotectic state have been calculated. It is shown that the effect of salting-out 2-(2-butoxyethoxy) ethanol from aqueous solutions with potassium nitrate increases with increasing temperature. The concentration of 2-(2-butoxyethoxy) ethanol in the organic phase of monotectics at 90.0° C is 90 wt.% with a distribution coefficient of 897.

Meta‐Separation: Complete Separation of Organic–Water Mixtures by Structural Property of Metamaterial

AbstractThe separation of liquid mixtures has been studied for a long time. Separation is based on the difference in physical properties including pore size and electrostatic interaction. Therefore, there are many difficulties in separation of materials having similar physical properties such as ethanol–water and 1,4‐dioxane–water mixtures. While pervaporation based on a difference in transport rates by permeability through a membrane has been suggested, it still has many difficulties such as high energy consumption and huge facilities. Yet there is an existing technical gap to remove trace amounts of organics dissolved in water. Here, a novel separation strategy employing a metamaterial, called meta‐separation using the exotic structural property of metamaterials rather than electrostatic characteristics is reported. The structural properties of metamaterials provide various functions of super‐hydrophobicity based on roughness of surface, the strong capillary effect based on nanopore, and huge void for great absorption of organics. It exhibits a water contact angle of 151.3° and high adhesive property from nanopore. On the other hand, ethanol is immediately absorbed up to 93 wt%. These differences make it possible to quickly and easily eliminate organics dissolved in water. Furthermore, their applications are expected to achieve functions in environmental remediation, biofuel separation process, etc., without large‐scale facilities.