Separation Of Organic Liquid Mixtures Research Articles

Carbon nanotube assisted highly selective separation of organic liquid mixtures

Carbon nanotubes (CNTs) are prominent candidates for the separation of various polar and non-polar liquid mixtures. Numerous studies report the application of CNTs for isolating the binary aqueous liquid mixtures, but very few demonstrate the separation of organic liquid mixtures. Here, we investigate the selective permeation of cosolvents such as ethanol, isopropanol, n-butanol, acetone, and tetrahydrofuran into the CNTs from the binary mixtures of benzene using molecular dynamics simulations. Our findings reveal that extremely small-sized (11,0) CNTs achieve almost 100% cosolvent capture selectivity in all five equimolar binary mixtures. In considerably bigger-sized CNTs such as (20,0), benzene accumulates inside along with the cosolvent, however, forms a well-distinguishable layer close to the interior wall of CNTs analogous to the second layer of a double-walled CNT. The results confirm that the liquid capture and selectivity are governed by the polarity and molecular size of the solvents as well as the CNT diameters.

Calculating osmotic pressure of liquid mixtures by association theory for sustainable separating of solvents by membrane processes

Recent years, the separation of organic liquid mixtures achieved by organic solvent nanofiltration (OSN), organic solvent reverse osmosis (OSRO), and organic solvent forward osmosis (OSFO) has gained a great momentum. In the methods, it is of particular importance to know the osmotic pressure of liquid mixtures for the correct process design. Although the Van’t Hoff law is frequently employed to estimate the osmotic pressure of such mixtures, unprecedented serious errors might be added to the results. In this study, the osmotic pressure of numerous binary liquid mixtures is predicted using the original definition of osmotic pressure along with the cubic plus association (CPA) equation of state (EoS) and the Van’t Hoff equation at various temperatures and compositions. CPA EoS considers hydrogen bonding effects in associating compounds (those with hydrogen bonds such as water and alcohols). The obtained results reveal that unlike the Van’t Hoff equation (the average deviation = 19.95 bar), the original definition of osmotic pressure with the aid of CPA EoS (the average deviation = 3.86 bar) can properly predict the osmotic pressure of the studied mixtures. Our findings are beneficial for various techniques utilized in the separation of organic liquid mixtures.

Organic solvent mixture separation using fluorine-incorporated thin film composite reverse osmosis membrane

Organic solvent reverse osmosis (OSRO) is currently considered as an energy-efficient membrane technology for separation of organic liquid mixtures.

Organic Liquid Mixture Separation Using an Aliphatic Polyketone-Supported Polyamide Organic Solvent Reverse Osmosis (OSRO) Membrane.

Energy-efficient membrane technology has received tremendous attention for the separation of organic molecules; however, the separation of molecules of less than 100 Da has remained challenging. Herein, a membrane fabricated from interfacial polymerization on a polyketone support was used as an organic solvent reverse osmosis (OSRO) membrane for the separation of organic liquid mixtures. The chemically stable and highly cross-linked selective layer exhibited outstanding separation factors toward large nonpolar molecules from small polar ones with high fluxes. For example, separation factors of 8.4, 11.1, 14.9, and 38.0 were achieved toward toluene, pentane, hexane, and heptane (10 wt % in mixtures), respectively, from methanol solution at 3 MPa, with fluxes around 5 LMH. This membrane outperformed the currently available reverse osmosis membrane and organic solvent nanofiltration membranes in terms of stability and separation factor. This work promotes the development of OSRO separation of organic liquid mixtures without phase change.

Matchstick-like metal-organic framework-based superwetting materials for efficient multiphase liquid separation via filtration or adsorption

Superwetting materials with opposite affinities to water and oil have been widely applied for separating oil-water system. However, separation of organic liquid mixtures remains great challenge owing to its lower surface tension differences. Herein, solvent-induced separation strategy based on the polarity reaction between the liquids and material is proposed to build superwetting surfaces in polar-apolar liquids system. The copper mesh/foam (CuM/CuF) were firstly etched via an alkaline catalyzed oxidation method to form microneedles, and then coordinated with the organic ligands to generate Metal-organic framework (MOF) nanorods on the microneedles that defined as CuM@MOF/CuF@MOF, and further modified with alkanethiol, finally obtaining the CuM@MOF@Thiol or CuF@MOF@Thiol. The synergetic effect of the structural morphology and chemical compositions realized the controllable regulation of their wettability and adsorption property. The CuM@MOF as filtration membranes that performed superlyophobicity to apolar liquid under polar liquids was used to separate the heavy polar liquid-light apolar liquid mixtures. Besides, the CuM@MOF@Thiol with superlyophbicitiy to polar liquids under apolar liquids could be applied for the filtrating separation of light polar liquid-heavy apolar liquid mixtures. Moreover, the CuF@MOF with superlyophilic to polar liquids under apolar liquids and CuF@MOF@Thiol with superlyophilic to apolar liquids under polar liquids could be applied for on-demand adsorbing separation of both the heavy polar-light apolar and light poalr-heavy apolar mixtures. Thus, the superwetting MOF-based mesh/foam can selectively absorb one phase while repel the immiscible phase with opposite polarity, realizing high-efficiency separation of organic liquids via selective filtrating or absorbing.

Liquid-Liquid Equilibrium Data for the System N-Octane + Toluene + DES at 293.15 and 313.15 K and Atmospheric Pressure

Deep eutectic solvents (DESs) are promising alternative for ionic liquids due to their low cost and sustainability. Considerable attention is paid on the ability of DES to replace ionic liquids in the separation of organic liquid mixtures via extraction. In this sense, it is important to determine the physicochemical parameters of liquid-liquid equilibrium for the industrially significant mixtures and deep eutectic solvents. In the present work a mixture of n-octane, toluene and DES based on choline chloride and malonic acid was studied at 293.15, 313.15 K and atmospheric pressure. Tie-lines were obtained and ability of deep eutectic solvents to separate aliphatic-aromatic mixture was analyzed. Experimental liquid-liquid equilibrium data were fit with the NRTL model, and interaction parameters of components were obtained and discussed.

A Robust Cu(OH)2 Nanoneedles Mesh with Tunable Wettability for Nonaqueous Multiphase Liquid Separation.

The separation of organic liquid mixtures is achieved by Cu(OH)2 nanoneedle-covered copper mesh based on the difference of the liquid surface tension. The as-prepared membrane allows the penetration of organic liquid with smaller surface tension and blocks the higher. Thus, the effective separation of these two organic liquids can be achieved.

Grafting of cellulose acetate with ionic liquids for biofuel purification by a membrane process: Influence of the cation

A new strategy was developed for grafting ionic liquids (ILs) onto cellulose acetate in order to avoid IL extraction and improve its performance for ethyl tert-butyl ether (ETBE) biofuel purification by the pervaporation membrane process. This work extended the scope of IL-containing membranes to the challenging separation of organic liquid mixtures, in which these ILs were soluble. The ILs contained the same bromide anion and different cations with increasing polar feature. The membrane properties were strongly improved by IL grafting. Their analysis in terms of structure-property relationships revealed the influence of the IL content, chemical structure and chemical physical parameters α, β, π* in the Kamlet–Taft polarity scale. The ammonium IL led to the best normalized flux of 0.182kg/m2h for a reference thickness of 5μm, a permeate ethanol content of 100% and an outstanding infinite separation factor for the azeotropic mixture EtOH/ETBE at 50°C.

Permeation and separation of organic liquid mixtures through liquid‐crystalline polymer networks

AbstractA side‐chain liquid‐crystalline polymer (LCP) was synthesized by the addition of the mesogenic monomer to poly(methyl siloxane) in presence of a Pt‐catalyst. When an aqueous solution of 10wt% ethanol was permeated through a LCP membrane by pervaporation at various temperatures, the permeation rate increased with increasing temperature and drastically changed at glass‐nematic (Tg) and nematic‐isotropic (TNI) transition temperatures of the LCP membrane. The LCP membrane exhibited the waterpermselectivity in the glassy and liquid‐crystalline states. The ethanol concentration in the permeate increased with increasing permeation temperature and the LCP membrane changed from the waterpermselectivity to the ethanol‐permselectivity around TNI. These results suggested that the permselectivity was influenced by the change of the LCP membrane structure, that is, its state transformation. It was found that a balance of the orientation of mesogenic groups and flexibility of siloxane chains is very important for the permeability and selectivity.

Separation of Organic Liquid Mixtures by Thermal Diffusion

Separation of Organic Liquid Mixtures by Thermal Diffusion