Design and manufacture of emulsion liquid membrane based on various amine extractants for separation and extraction of succinic acid from fermentation broth

The aim of this study was to design a new emulsion liquid membrane(ELM)system for the separation of succinic acid from aqueous solutions.The concentration of succinic acid varied from 20 to 60 mmol·L^(-1).The prepared ELM system includes tributylamine(TBA)as a carrier,commercial kerosene as a solvent,Span 80 as a surfactant,and Na2CO3as a stripping agent.In order to control the membrane swelling,different values of cyclohexanone were added to the membrane phase.The effect of various empirical variables on the extraction of the succinic acid such as acid concentration in the feed solution,initial feed concentration,carrier concentration,the stirring speed of the extraction,Na2CO3,surfactant,and cyclohexanone concentrations,and treat ratio in the ELM system.The best result was obtained when TBA was used as the carrier.The final acid extraction efficiency was independent of pH variations of the aqueous feed solution.The extraction of succinic acid solution with a concentration of 40 mmol·L^(-1)was improved by increasing the treat ratio 1:7-1:3,stripping phase concentration 0.5-1.5 mol·L^(-1),stirring speed 300-500 r·min^(-1)and cyclohexanone concentration in the membrane phase 1.2-1.6 mol·L^(-1).No considerable effect on the extraction rate was observed for the carrier concentration in the membrane phase.But,the surfactant concentration in the feed phase showed a dual effect on the extraction efficiency.

Study of Transport and Separation of Rare Earth Ions through the Emulsion Liquid Membrane of Bis(2,4,4-trimethylpentyl)phosphinic Acid-Span 80-Toluene

It is indicated from a study of transport of rare earth ions through the emulsion liquid mem- brane of bis(2,4,4-trimethylpentyl)phosphinic acid-Span 80-toluene that transporting rare earth ions com- pletely and rapidly was realized under the optimum experimental conditions:1.0×10^(-3)～3.0×10^(-3)mol/L bis(2,4,4-trimethylpentyl)phosphinic acid and 2%～4%(W/V)Span 80 in toluene solution as membrane phase,0.50～2.0 mol/L HCl as inner phase,rare earth ion solutions with pH 3.5～5.0 as outer phase.Ac- cording to the differences of transport behavior for rare earth ions,it is possible to separate rare earth ions from mixed solutions of rare earth ions by this liquid membrane system.

New high permeable polysulfone/ionic liquid membrane for gas separation

In this study,the effects of 1-Ethyl-3-methylimidazolium tetrafluoroborate ionic liquid on CO2/CH4 separation performance of symmetric polysulfone membranes are investigated.Pure polysulfone membrane and ionic liquid-containing membranes are characterized.Field emission scanning electron microscopy(FE-SEM)is used to analyze surface morphology and thickness of the fabricated membranes.Energy dispersive spectroscopy(EDS)and elemental mapping,Fourier transform infrared(FTIR),thermal gravimetric(TGA),X-ray diffraction(XRD)and Tensile strength analyses are also conducted to characterize the prepared membrane s.CO2/CH4 separation performance of the membranes are measured twice at 0.3 MPa and room temperature(250 C).Permeability measurements confirm that increasing ionic liquid content in polymer-ionic liquid membranes leads to a growth in CO2 permeation and CO2/CH4 selectivity due to high affinity of the ionic liquid to carbon dioxide.CO2 permeation significantly increases from 4,3 Barrer(1 Barrer=10^-10 cm^3(STP)·cm·m^-2·s^-1·cmHg^-1,1 cmHg=1.333 kPa)for the pure polymer membrane to 601.9 Barrer for the 30 wt%ionic liquid membrane.Also,selectivity of this membrane is improved from 8.2 to 25.8.mixed gas te sts are implemented to investigate gases interaction.The results showed,the disruptive effect of CH4 molecules for CO2 permeation lead to selectivity decrement compare to pure gas te st.The fabricated membranes with high ionic liquid content in this study are promising materials for industrial CO2/CH4 separation membranes.

CO_2/N_2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures

The high price and toxicity of ionic liquids(ILs) have limited the design and application of supported ionic liquid membranes(SILMs) for CO_2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200(PEG200) mixtures were selected to prepare novel SILMs because of their green and costeffective characterization, and the CO_2/N_2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO_2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO_2 permeability ranged in 343.3–1798.6 barrer and high CO_2/N_2 selectivity from 7.9 to 34.8.It was also found that the CO_2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to38 m Pa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.

AgBF_4/[emim][BF_4] supported ionic liquid membrane for carbon monoxide/nitrogen separation

In this paper,AgBF_4/[emim][BF_4] supported ionic liquid membranes(SILMs) were prepared successfully for CO/N_2 separation using nitrogen pressure immobilization procedures.The incorporation of AgBF_4 could decrease membrane weight loss,improve the pressure-resistant ability,and keep the critical pressure(0.45 MPa) of the SILMs.The high viscosity and undissolved Ag BF_4 solids in membrane liquid would disturb gas molecular transport through membrane and give rise to the gas transport resistance.Therefore,the gas permeability decreased remarkably with increasing AgBF_4 carrier content in the membrane.When the molar ratio of AgBF_4 to [emim][BF_4] increased from 0:1 to 0.3:1,the CO/N_2 selectivity of the SILMs showed a great increase from ～1 to ～9 at 20 °C and 0.4 MPa,suggesting that AgBF_4 was an effective carrier for CO facilitated transport.The permeabilities of N_2 and CO increased at higher transmembrane pressure,indicating that molecular transport would dominate the transport process at high pressure.The temperature-dependent gas permeability followed the Arrhenius equation.Moreover,the differences between the activation energies of CO and N_2 became larger after introducing AgBF_4,resulting in more obvious decrease in the CO/N_2 selectivity at higher operating temperature.

Intensification of zirconium and hafnium separation through the hollow fiber renewal liquid membrane technique using synergistic mixture of TBP and Cyanex-272 as extractant

The novel synergistic mixture of TBP and Cyanex-272 is used as the extractant in the hollow fiber renewal liquid membrane(HFRLM) technique for Zr/Hf separation.The effects of the chemical and operational parameters such as HNO3 concentration in the donor phase,NH4 F concentration in the acceptor phase,Cyanex-272 and TBP concentration in the liquid membrane phase,the lumen and shell side flow rates,and aqueous/organic volume ratio on the mass transfer and separation performance of HFRLM method were investigated.The obtained results reveal the intensification potential of proposed HFRLM technique for selective extraction of Zr over Hf with separation factor higher than 100.The HFRLM method provides two times higher mass transfer flux in comparison with hollow fiber supported liquid membrane(HFSLM).Also,the HFRLM method shows satisfactory stability for 700 min of continuous operation.The Zr ion transport through the LM phase follows the coupled co-transport mechanism and the diffusion in the renewal layer is recognized as the rate-controlling step in the HFRLM process.Moreover,the Zr mass transfer coefficient and molar flux in the HFRLM method are calculated in the range of 1×10^-8 to 8.4×10^-7 m·s^-1 and 4.9×10^-6 to 20.1×10^-6 mol·m^-2·s^-1,respectively.

Hollow Fiber Supported Liquid Membrane for Separation and Recovery of ^152+154Eu and ⁹⁰Sr from Aqueous Acidic Wastes

Separation and recovery of 152+154Eu and 90Sr from radioactive waste using tracer concentration from active material from waste tank in the ET-RR1 Egypt via hollow fiber supported liquid membrane (HFSLM) were achieved. The Polypropylene was used as supporter to carrier 0.5M Cyanex301/kerosene (bis(2,4,4-trimethylpentyl)dithiophosphinic acid and 0.1MEDTA as stripping of 152+154Eu and 90Sr ions from nitrate medium at pH ~3.6. The separation factor was found to be ~4 for 152+154Eu over 90Sr. The aqueous feed of mass transfer coefficient (ki) and the organic mass transfer coefficient (km) were calculated to be (1.52 and 4.5) × 10﹣2cm/s, respectively. In addition, the mass transfer modeling was performed and the validity of the developed model from experimental data was found to join in well with the theoretical values when the Cyanex301 concentration is higher than 1% (v/v). The number of cycles evaluated for complete separation of 152+154Eu and 90Sr is five cycles.

Temperature-regulation liquid gating membrane with controllable gas/liquid separation

Membrane separation technology with the ability to regulate gas/liquid transport and separation is critical for environmental fields, such as sewerage treatment, multiphase separation, and desalination. Although numerous membranes can dynamically control liquid-phase fluids transport via external stimuli, the transport and separation of gas-phase fluids remains a challenge. Here, we show a temperature-regulation liquid gating membrane that allows in-situ dynamically controllable gas/liquid transfer and multiphase separation by integrating a thermo-wettability responsive porous membrane with functional gating liquid. Experiments and theoretical analysis have demonstrated the temperature-regulation mechanism of this liquid gating system, which is based on thermo-responsive changes of porous membrane surface polarity, leading to changes in affinity between the porous membrane and the gating liquid. In addition, the sandwich configuration with dense Au-coated surfaces and heterogeneous internal components by a bistable interface design enables the liquid gating system to enhance response sensitivity and maintain working stability. This temperature-regulation gas/liquid transfer strategy expands the application range of liquid gating membranes,which are promising in environmental governance, water treatment and multiphase separation.

Artificial neural network based modeling of liquid membranes for separation of dysprosium

In recent years,the liquid membrane process has been widely investigated to remove rare earth metals.However,transport modeling of this process requires the accurate values of several parameters,which are difficult to measure.Thus,the accurate simulation of this process is a challenging task.In this study,the artificial neural network(ANN)based approach is used to model the liquid membrane process for removing dysprosium.Experimental results from a previous study were used to train the ANN.Initially,the number of neurons in the hidden layer was optimized.The minimum mean squared error between experimental results and model predictions is found with ten neurons.Model predictions were successfully validated with experimental results with correlation factor(R)of 0.9987,which confirms the authenticity of the trained network.Trained ANN was then used to study the effects of different operating parameters on transport rate.The higher volume ratio of membrane solution to feed solution(3-4)with 50-60 min of operation,higher feed pH(5),HCl concentration in stripping solution of 2 mol/L,and moderate concentration of carrier species(0.5 mol/L)with 0.5×10^(-4) mol/L dysprosium initial concentration are found to be optimum values of operating conditions for maximizing the transport rate.

RATE MODEL FOR PHASE SEPARATION OF WATER-IN-OIL EMULSION IN LIQUID SURFACTANT MEMBRANE PROCESS AT HIGH A.C.VOLTAGE

A new mechanism of electric demulsification was proposed and the coalescence behavior of fine waterdrops in oil under electric field was discussed in detail On this basis,a mathematical description for phaseseparation of emulsion in electric field has been derived and proved to be in good agreement with experimentaldata.Conditions influenced the electric coalescence was examined in a batch pulsed A.C.electric demulsifier.

Fabrication of poly(vinylidene fluoride) membrane via thermally induced phase separation using ionic liquid as green diluent

Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.

Separation of Eu^3＋ Using a Novel Dispersion Combined Liquid Membrane with P507 in Kerosene as the Carrier

The separation of Eu^3 ＋is studied with a dispersion combined liquid membrane（DCLM）,in which polyvinylidene fluoride membrane（PVDF）is used as the liquid membrane support,dispersion solution containing HCl solution as the stripping solution,and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester（P507）dissolved in kerosene as the membrane solution.The effects of pH value,initial concentration of Eu3 ＋and different ionic strength in the feed phase,volume ratio of membrane solution to stripping solution,concentration of HCl solution, concentration of carrier,different stripping agents in the dispersion phase on the separation are investigated.The optimum condition for separation of Eu3 ＋is that concentration of HCl solution is 4.0 mol·L 1,concentration of carrier is 0.16 mol·L 1,and volume ratio of membrane solution to stripping solution is 30︰30 in the dispersion phase, and pH value is 4.2 in the feed phase.The ionic strength has no significant effect on separation of Eu3 ＋.Under the optimum condition,when the initial concentration of Eu3 ＋is 0.8×10 4mol·L 1,the separation percentage of Eu 3＋is 95.3%during the separation time of 130 min.The kinetic equation is developed in terms of the law of mass diffusion and the theory of interface chemistry.The diffusion coefficient of Eu3 ＋in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and their values are 1.48×10 7m 2·s 1and 36.6μm,respectively.The results obtained are in good agreement with literature data.

TEMPERATURE DEPENDENCE OF AIR SEPARATION OF LIQUID CRYSTALLINE TRIHEPTYL CELLULOSE/ETHYL CELLULOSE MEMBRANES

Triheptyl cellulose/ethyl cellulose(3/97)binary blend membranes were prepared from tetrahydrofuran,chloroform and dichloromethane solutions and their air separation capabit- ities were studied at different temperatures.With increasing temperature from 25 to 85℃,the flux QOEA of O_2-enriched air(OEA),O_2 permselectivity and the O_2 concentration Yo_2 in the OEA all increase.The membranes show a unique trend in their Yo_2～QOEA relationship,that is,the air separation capability increases simultaneously with the OEA permeation capability.The magnitudes of QOEA and Yo_2 for 17μm-thick membrane after the testg time of 36hours at 70℃ are 5×10^(-4)cm^3 (STP)/s·cm^2 and 37.6%,respectively.The air separation capability depends slightly on membrane forming solvents.

Separation of Samarium(Ⅲ)and Gadolinium(Ⅲ)by A Push-pull Liquid Membrane System

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Permeability and Selectivity of Sulfur Dioxide and Carbon Dioxide in Supported Ionic Liquid Membranes

Permeabilities and selectivities of gases such as carbon dioxide （CO2）, sulfur dioxide （SO2）, nitrogen （N2） and methane （CH4） in six imidazolium-based ionic liquids （[emim][BF4], [bmim][BF4], [bmim][PF6], [banim][BF4], [bmim][Tf2N] and [emim][CF3SO3]） supported on polyethersulfone microfiltration membranes are investigated in a single gas feed system using nitrogen as the environment and reference component at temperature from 25 to 45℃ and pressure of N2 from 100 to 400 kPa. It is found that SO2 has the highest permeability in the tested supported ionic liquid membranes, being an order of magnitude higher than that of CO2, and about 2 to 3 orders of magnitude larger than those of N2 and CH4. The observed selectivity of SO2 over the two ordinary gas components is also striking. It is shown experimentally that the dissolution and transport of gas components in the supported ionic liquid membranes, as well as the nature of ionic liquids play important roles in the gas permeation. A nonlinear increase of permeation rate with temperature and operation pressure is also observed for all sample gases. By considering the factors that influence the permeabilities and selectivities of CO2 and SO2, it is expected to develop an optimal supported ionic liquid membrane technology for the isolation of acidic gases in the near future.

Assembling ionic liquid into porous molecular filler of mixed matrix membrane to trigger high gas permeability,selectivity,and stability for CO_(2)/CH_(4) separation

As an emerging zero-dimensional nano crystalline porous material,porous organic cages(POCs)with soluble properties in organic solvents,are promising candidates as molecular fillers in mixed matrix membranes(MMMs).The pore structure of POCs should be adjusted to trigger efficient gas separation performance,and the interaction between filler and matrix should be optimized.In this work,ionic liquid(IL)was introduced into the molecular fillers of CC3,to construct the IL@CC3/PIM-1 membrane to effectively separate CO_(2) from CH_(4).The advantages of doping IL include:(1)narrowing the cavity size of POCs from 4.4 to 3.9Åto enhance the diffusion selectivity,(2)strengthening the CO_(2) solubility to heighten the gas permeability,and(3)improving the compatibility between filler and matrix to upgrade membrane stability.After the optimization of the membrane composite,the IL@CC3/PIM-1-10%membrane possesses the CO_(2) permeability of 7868 Barrer and the CO_(2)/CH_(4) selectivity of 73.4,which compared to the CC3/PIM-1-10%membrane,improved by 15.9%and 106.2%,respectively.Furthermore,the membrane has maintained a stable separation performance at varied temperatures and pressures during the long-term test.The proposed method offers an efficient way to improve the performance of POCs-based MMMs in gas separation.

COF-based membranes for liquid phase separation:Preparation,mechanism and perspective

Covalent organic frameworks(COFs)are a new kind of crystalline porous materials composed of organic molecules connected by covalent bonds,processes the characteristics of low density,large specific surface area,adjustable pore size and structure,and easy to functionalize,which have been widely used in the field of membrane separation technology.Recently,there are more and more researches focusing on the preparation methods,separation application,and mechanism of COF membranes,which need to be further summarized and compared.In this review,we primarily summarized several conventional preparation methods,such as two-phase interfacial polymerization,in-situ growth on substrate,unidirectional diffusion method,layer-by-layer assembly method,mixed matrix membranes,and so on.The advantages and disadvantages of each method are briefly summarized.The application potential of COF membrane in liquid separation are introduced from four aspects:dyeing wastewater treatment,heavy metal removal,seawater desalination and oil-water separation.Then,the mechanisms including pore structure,hydrophilic/hydrophobic,electrostatic repulsion/attraction and Donnan effect are introduced.For the efficient removal of different kind of pollutions,researchers can select different ligands to construct membranes with specific pore size,hydrophily,salt or organic rejection ability and functional group.The ideas for the design and preparation of COF membranes are introduced.Finally,the future direction and challenges of the next generation of COF membranes in the field of separation are prospected.

Poly(amide-6-b-ethylene oxide)/[Bmim][Tf2N] blend membranes for carbon dioxide separation

Poly（amide-6-b-ethylene oxide）（Pebax1657）/1-butyl-3-methylimidazo-lium bis[trifluoromethyl）sulfonyl]-imide（[Bmim][Tf2N]） blend membranes with different [Bmim][Tf2N] contents were prepared via solution casting and solvent evaporation method. The permeation properties of the blend membranes for CO2, N2,CH4 and H2 were studied, and the physical properties were characterized by differential scanning calorimeter（DSC） and X-ray diffraction（XRD）. Results showed that [Bmim][Tf2N] was dispersed as amorphous phase in the blend membranes, which caused the decrease of Tg（PE） and crystallinity（PA）. With the addition of [Bmim][Tf2N], the CO2 permeability increased and reached up to approximately 286 Barrer at 40 wt%[Bmim][Tf2N], which was nearly double that of pristine Pebax1657 membrane. The increase of CO2 permeability may be attributed to high intrinsic permeability of [Bmim][Tf2N], the increase of fractional free of volume（FFV） and plasticization effect. However, the CO2 permeability reduced firstly when the [Bmim][Tf2N]content was below 10 wt%, which may be due to that the small ions of [Bmim][Tf2N] in the gap of polymer chain inhibited the flexibility of polymer chain; the interaction between Pebax1657 and [Bmim][Tf2N]decreased the content of EO units available for CO2 transport and led to a more compact structure. For Pebax1657/[Bmim][Tf2N] blend membranes, the permeabilities of N2, H2 and CH4decreased with the increase of feed pressure due to the hydrostatic pressure effect, while CO2 permeability increased with the increase of feed pressure for that the CO2-induced plasticization effect was stronger than hydrostatic pressure effect.

Enrichment of Trace Cerium by Liquid Membrane and Its Determination by Spectrophotometry

Introduction Since it was discovered in 1968,liquid membrane separation technique has been widely studied,particularly in separating or recovering some metal ions.It is a novel study that trace substances in analytical chemistry are enriched by liquid membrane.There have been few reports on enriching cerium by emulsion liquid membrane (ELM) now.Therefore,authors studied the liquid membrane methed for enriching trace cerium.The sensibility measuring cerium by spectrophotometry was increased greatly.