Emulsion Prevention with Supported Liquid Membrane Permeation

The urge to achieve climate protection goals and a more prevalent interest in finding alternatives to fossil fuel‐based products focus attention increasingly on cascade raw material utilization, respectively, to intensify commercial production processes. The present project provides a study on the combination of liquid‐liquid extraction and esterification using the system acetic acid/octanol and 4‐dodecylbenzenesulfonic acid as catalyst. The surfactant 4‐dodecylbenzenesulfonic acid causes emulsification during extraction, but emulsification was successfully avoided by using supported liquid membrane permeation equipment.     

Selective Transport of Alkali and Alkaline Earth Metallic Ions through a Supported Liquid Membrane Containing Tripentyl Phosphate as a Carrier

Abstract

A selective transport system for alkali and alkaline earth metallic ions with a perchlorate ion as a pairing ion species through a supported liquid membrane (SLM) containing tripentyl phosphate (TPP) as a carrier is described. The SLM used is a porous polypropylene membrane impregnated with TPP solution in o-nitrophenyloctylether. The effects of the pairing ion species, the initial perchlorate concentration, and the TPP concentration on metallic ion transportability are examined under various experimental conditions. The permeation velocities of the metallic ions in the transport system followed the sequence Li⁺?Na⁺>K⁺>Mg²⁺; that is, a highly selective transport for Li⁺ ion was observed. Compared with the transport rates of alkali metallic ions, those of transition metallic ions such as Cu²⁺ and Fe³⁺ ions are very low. The permeation velocities of alkali and alkaline earth metallic ions through an SLM are dependent on the concentrations of perchlorate and TPP. Equations for the permeation velocities of Li⁺, Na⁺, K⁺, and Mg²⁺ ions through an SLM, based on two concentrations of perchlorate and TPP, are proposed.     

Highly Selective Li+ Ion Transport by Porous Molybdenum-Oxide Keplerate-Type Nanocapsules Integrated in a Supported Liquid Membrane

Porous Keplerate-type molybdenum-oxide nanocapsules – encapsulated into cationic surfactants – act as transporting systems for alkali cations through supported liquid membranes. The transport is based on the ability of the nanocapsules containing water molecules inside their cavities to attract and release the cations. This results in specific nanoscaled translocation pathways, based on corresponding dynamic diffusional domains within the liquid bulk membrane phase, due to the self-assembly of the capsules. Li⁺ cations are preferentially extracted and transported, thus allowing separation from Na⁺ and K⁺ cations, which are not transported to the receiving phase.     

Carrier-Mediated Transport of Rare Earth Ions through Supported Liquid Membranes

Abstract

Fluxes of rare earth ions (Sc³⁺, Y³⁺, La³⁺, Sm³⁺, and Lu³⁺) across supported liquid membranes using mixtures of nitrophenyl octyl, heptyl, or phenyl ethers and tris(2-n-butoxyethyl) phosphate (TBEP) as solvents and some β-diketones as carriers were determined. The effects of membrane composition, pH of the source phase, and carrier concentration on the flux are demonstrated. The effect of membrane composition is further discussed from the values of the membrane potential and the viscosity and electrical conductivity of the solvents. A maximal flux of lanthanum is observed for the membranes by using mixtures consisting of equal volumes of the nitrophenol derivative and TBEP. The fluxes of the rare earths, except scandium, decrease rapidly with decreasing pH difference between the source and receiving phases. The difference in flux among the rare earths, except scandium, is small. The flux increases in the carrier order benzoyl- > thenoyl- > furoyltrifluoroacetones. The lanthanum flux is proportional to the carrier concentration.     

Transport of Europium through Supported Liquid Membrane Containing Dihexyl-N,N-diethylcarbamoylmethylphosphonate

Abstract

The transport of europium has been studied through a supported liquid membrane (SLM) impregnated with dihexy-N,N-diethylcarbamoylmethylphosphonate (CMP). Europium was effectively extracted from the perchlorate solution into SLM, but was insufficiently stripped to a dilute acid solution. The addition of 1-decanol improved the stripping process, and quantitative transport of europium was achieved. By the combination of two SLM systems consisting of diiso-decylphosphoric acid and CMP, europium was transported from the feed solution (0.1 M HNO₃) through the intermediate solution (1 M HclO₄ + 4 M NaClO₄) to the product solution (0.1 M HNO₃) and effectively concentrated by a factor of about 20.     

Selective Transport of Cu2+ Ions through Bulk Liquid Membrane System Mediated by Erythromycin Ethyl Succinate

The carrier mediated transport of Cu²⁺ ions from an aqueous medium has been examined. The ability of Erythromycin Ethyl Succinate (EES) as a carrier to form a complex with Cu²⁺ ions and transport them to the receiving phase is reported. The fundamental parameters influencing the transport of Cu²⁺ ions such as the pH in the source and receiving phases and concentration of the stripping agent in the receiving phase have been optimized and accordingly, the amount of Cu²⁺ transported across the liquid membrane after 5 h was 94.3 ± 1.8% in the presence of L-histidine as a suitable stripping agent. Moreover, the selectivity and efficiency of Cu²⁺ ions transport from aqueous solution over other cations in ternary and quaternary mixtures have been investigated. The results indicate that our fabricated membrane is very sensitive toward Cu⁺² ions in the presence of heavy metal ions.     

Phenol Removal by Supported Liquid Membranes

Abstract

This paper examines the application of the supported liquid membrane (SLM) to phenol removal. n-Decanol was proven to be a suitable membrane liquid. The phenol transfer kinetics through the SLMs is quantitatively estimated according to models based on the resistance-in-series concept. The models can be modified to describe the performance of decayed SLMs and thereby provide insight into the effect of membrane liquid loss and penetration of aqueous solutions on the phenol flux. An experimental method is described for the measurement of mass transfer coefficients in the bulk phases using the well-characterized Anopore membrane.     

Mass Transfer Investigation of Liquid Membrane Transport of Gold (III) by Methyl Isobutyl Ketone Mobile Carrier

Extraction of Au^III ions by an emulsion liquid membrane (ELM) system with methyl isobutyl ketone (MIBK) as the mobile carrier and also liquid‐liquid extraction of Au^III from aqueous solutions have been studied. Experiments on the transport of the gold ions in a liquid‐liquid extraction system and stripping of the extracted ions from the organic phase as well as the extraction by a three‐phase W/O/W emulsion liquid membrane system have been performed. The results showed that even when the distribution coefficient of the diffusing species in the phases is small, the extraction by emulsion liquid membranes would be an effective process. A first‐order extraction rate was proposed and examined for the extraction system.     

支撑液膜分离技术及其在烟气脱硫中的研究

支撑液膜技术作为一种高选择性和高渗透性的膜分离技术得到了越来越多的应用。本文对过去30多年来有关支撑液膜的研究进展作了详述,主要包括分离机理、不稳定性机理以及解决不稳定的方法等方面,并简单介绍了支撑液膜技术在烟气脱硫中的研究应用,并对该方向进行了展望。     

Extraction of Rhodium Chlorocomplexes and Acid through a Supported Liquid Membrane of Kelex 100

Abstract

The supported liquid membrane (SLM) technique was employed to effect the separation of Rh Chlorocomplexes from hydrochloric acid solutions. The liquid membrane consisted of an alkylated 8-hydroxyquinoline extractant (Kelex 100), tridecanol, and kerosene. The nonaquated Rh complexes were transported through the membrane upon ion-pair formation with protonated Kelex 100 molecules. The ion-pair was then dissociated at the strip side of the membrane, releasing the Rh values. The main driving force for this transport process was the acid activity gradient across the membrane. The permeation of acid and water, which were cotransported with the Rh complexes, was partially prevented upon addition of NaCl to the strip phase. However, the accumulation of Cl^? ions in the strip phase, in turn, slowed down the extraction of Rh. Optimum Rh extraction performance was obtained when a feed of 2.5 M HC1 and a strip solution of pH 1 were used. Under these conditions the membrane was found to be very stable for at least a period of 72 hours (maximum period tested) while the rate of extraction was found to be 2.8 × 10^?6 mol·s^?1·m^?2.     

Transport of Europium(III) through Supported Liquid Membrane Containing Diisodecylphosphoric Acid

Abstract

Carrier mediated transport of europium has been investigated by the use of a flat-sheet membrane impregnated with diisodecylphosphoric acid (DIDPA). The addition of 1-octanol to the membrane improves the stripping process, and hence europium can be quantitatively transported from the feed solution of 0.1 M HNO₃ into the product solution of 5 M HNO₃. Its concentration in the feed solution decreases as [Eu] _f,t = [Eu] _f,0 exp (-k _obs t). The apparent rate constant (k _obs) increases with increasing carrier concentration and becomes nearly constant above 0.05 M DIDPA The europium flux is proportional to initial europium concentrations less than 10^?3 M, and becomes constant at high concentrations.     

The Transport of Copper(II) through Hollow Fiber Renewal Liquid Membrane and Hollow Fiber Supported Liquid Membrane

Abstract

In this paper, hollow fiber renewal liquid membrane (HFRLM) and hollow fiber supported liquid membrane (HFSLM) were used to simultaneously remove and recover copper(II) from aqueous solutions, and the transport performance of these two techniques were compared under the similar conditions for the system of CuSO₄ +D2EHPA in kerosene +HCl. The results showed that the HFRLM process was more stable than the HFSLM process. The HFRLM process had a higher overall mass transfer coefficient than that of HFSLM process in single-pass experiments. These were because the renewal effect of the liquid membrane layer could reduce the mass transfer resistance of the lumen side and replenish the loss of the membrane liquid in the HFRLM process. The transport results were better in the HFRLM process than that in the HFSLM process with recycling experiments. Therefore, HFRLM technique is a promising method for simultaneous removal and recovery of heavy metal from aqueous solutions.     

两相更新支撑液膜中金属二价镍的迁移行为研究(英文)

A novel disphase supplying supported liquid membrane(DSSLM),containing supplying feed phase and supplying stripping phase for transport behavior of Ni(II),have been studied.The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid(HDEHP) as the carrier in kerosene,and supplying stripping phase included HDEHP as the carrier in kerosene and HCl as the stripping agent.The effects of volume ratio of membrane solution to feed solution(O/F),pH,initial concentration of Ni(II) and ionic strength in the feed solution,volume ratio of membrane solution to stripping solution(O/S),concentration of H2SO4 solution,HDEHP concentration in the supplying stripping phase on transport of Ni(II),the advantages of DSSLM compared to the traditional supported liquid membrane(SLM),the system stability,the reuse of membrane solution and the reten-tion of membrane phase were studied.Experimental results indicated that the optimum transport of Ni(II) was ob-tained when H2SO4 concentration was 2.00 mol·L-1,HDEHP concentration was 0.120 mol·L-1,and O/S was 4:1 in the supplying stripping phase,O/F was 1︰10 and pH was 5.20 in the supplying feed phase.The ionic strength in supplying feed phase had no obvious effect on transport of Ni(II).When initial Ni(II) concentration was 2.00×10?4 mol/L,the transport percentage of Ni(II) was up to 93.1 % in 250 min.The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.     

苯酚体系支撑液膜不稳定性研究

The instability mechanisms of the supported liquid membrane using Celgard 2500 membranes as support and tributyl phosphate dissolved in kerosene as carrier for phenol transport was studied by electrochemical impedance spectroscopy. Emulsion formation is demonstrated to be one of the main causes for the instability of supported liquid membrane in the present system. The emulsion-facilitated conditions, such as higher membrane liquid concentration, faster stirring speed, lower salt concentration and higher HLB value, would accelerate the degradation of supported liquid membrane. Other mechanisms including solubility and os-motic pressure work together to increase the membrane liquid loss.     

Transport of Chromium(VI) through a Supported Liquid Membrane Containing Tri-n-octylphosphine Oxide

ABSTRACT

In this study the transport of chromium(VI) from aqueous solutions of pH 2–4 through a supported liquid membrane (SLM) with tri-n-octylphosphine oxide (TOPO) dissolved in kerosene as a mobile carrier was investigated. The transport flux of Cr(VI) increased with an increase in the concentrations of Cr(VI) in the feed phase and of TOPO in the membrane phase, but with a decrease in pH of the feed phase. Considering the equilibria of various Cr(VI) species in the aqueous phase and of the Cr(VI)—TOPO complexes formed in the membrane phase, a permeation model including the aqueous film diffusion of HCrO₄ ^? and Cr₂O₇ ^2? toward the membrane, the interfacial chemical reaction between them and TOPO, and the membrane diffusion of the Cr(VI)—TOPO complexes (H₂CrO₄(TOPO) and H₂Cr₂O₇(TOPO)₃) was proposed to describe the transport of Cr(VI) through the SLM. By best fitting the transport flux equations of Cr(VI) with the experimental data using the Rosenbrock method, the apparent mass-transfer coefficients of HCrO₄ ^? and Cr₂O_7^. across the aqueous film, and those of H₂CrO₄(TOPO) and H₂Cr₂O₇(TOPO)₃ across the membrane phase, were obtained. This work helps to clarify the transport mechanism of Cr(VI) through an SLM.     

Facilitated Transport of Zinc Chloride through Hollow Fiber Supported Liquid Membrane. Part 1. Transport Mechanism

Abstract

The facilitated transport of zinc chloride through a liquid membrane of tri-n-octylamine dissolved in n-dodecane with 2-ethylhexyl alcohol, supported on a microporous polyethylene hollow fiber, has been studied in a series of three papers. This first paper deals with the transport mechanism. The distribution of zinc chloride between the liquid membrane phase and the aqueous hydrochloric acid solution was clarified. The characteristics of the support membrane and of the flow system were examined through phenol transport experiments. The initial permeation rate of zinc chloride was explained by the sum of film resistances in the two aqueous phases and a membrane phase resistance     

Facilitated Transport of Zinc Chloride through Hollow Fiber Supported Liquid Membrane. Part 2. Membrane Stability

Abstract

The stability of a hollow fiber supported liquid membrane of tri-n-octylamine diluted in n-dodecane with 2-ethylhexyl alcohol was examined for the facilitated transport of zinc chloride. The liquid membrane was unstable when the feed and the strip aqueous solutions were not saturated with the organic phase used as the liquid membrane. This was found to be due to the dissolution of relatively soluble 2-ethylhexyl alcohol to the aqueous phases. When both aqueous phases were presaturated with the organic phase used, a rather constant flux could be maintained for a long time by the reimpregnation of the organic phase approximately once a day. The continuous impregnation of the organic phase to the support membrane drastically increased the stability of the liquid membrane, even without presaturation of the two aqueous phases with the organic phase     

液膜分离在金属离子分离中的应用研究

液膜分离是一种高效、快速、节能的新型分离技术。综述了液膜分离技术在金属离子分离和富集中的应用进展,并指出其发展前景。     

Transport of Cadmium(II) Ion through a Supported Liquid Membrane Containing a Bathocuproine

Abstract

The active transport of cadmium ions across a supported liquid membrane (SLM) containing a ligand based on a driving force supplied by the concentration gradient of the chloride ion is described. The SLM used is a microporous polypropylene membrane impregnated with a bathocuproine (4,7-diphenyl-2.9-dimethyl-1,10-phenanthroline) solution in dibenzyl ether as a carrier. The characteristics of the cadmium ion transport system are examined under various experimental conditions. The active transport of cadmium ions through an SLM is dependent on the concentrations of the cadmium ion, ligand, and chloride ion. An equation for the permeation velocity of cadmium ions, consisting of three important factors for this transport system, is proposed.