Facilitated Pertraction of p-Aminobenzoic Acid with Amberlite LA-2 in Presence of 1-Octanol

p-Aminobenzoic acid has been facilitated pertracted with Amberlite LA-2 dissolved in dichloromethane, using a U-shaped pertraction cell which allows obtaining the free liquid membrane. The pertraction has been a carrier out in the presence of 1-octanol added in the liquid membrane. The addition of the alcohol led to the increase for up to 3 times of the acid initial and final mass flows, this effect being directly related to the process variables (pH-gradient between the aqueous phases, carrier and alcohol concentrations inside the membrane phase, mixing intensity). But, the influence of 1-octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of PABA in the liquid membrane, and requiring the reevaluation and optimization of the acid reextraction from the membrane phase to the stripping one.     

Comparitive study on facilitated pertraction of succinic acid using TRI‐n‐octylamine without and with 1‐octanol

Succinic acid has been pertracted with TOA using free liquid membranes without or with 1‐octanol. The addition of the alcohol led to the increase of up to 2.8–3 times of the acid's initial and final mass flows. At the same time, the influence of 1‐octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of succinic acid into the liquid membrane. A mathematical model describing the acid accumulation inside the liquid membrane has been developed for pertraction systems without and with 1‐octanol and offers good concordance with the experimental data. © 2012 Canadian Society for Chemical Engineering     

Selective Separation of Cinnamic and p‐Methoxycinnamic Acids by Facilitated Pertraction

Abstract

Cinnamic acid can be selectively separated from p‐methoxycinnamic acid by facilitated pertraction with Amberlite LA‐2 dissolved in dichloromethane, using a U‐shaped pertraction cell which allows obtaining the free liquid membrane. The pertraction has been analyzed by means of initial and final mass flows, permeability and selectivity factors. The main factors which control the pertraction selectivity were identified to be the pH‐gradient between the feed and stripping phase and the mixing intensity of the aqueous phases. The maximum selectivity factor has been recorded for pH=2 of feed phase, pH=8 of stripping phase, rotation speed lower than 300 rpm, and carrier concentration higher than 40 g/l.     

Study on Facilitated Pertraction of Folic Acid in Pseudosteady-State Regime

The influences of the pH-gradient between the feed and stripping phases and of carrier concentration inside the membrane phase on the efficiency of facilitated pertraction of folic acid with Amberlite LA-2 in pseudosteady-state mode have been analyzed. The experiments have been carried out using a U-shaped pertraction cell which allowed to easily maintaining the liquid membrane between the two aqueous phases. On the basis of the experimental data and theoretical investigation on pseudosteady-state regime, two models describing the acid accumulation inside the liquid membrane by means of the permeability factor have been developed for two pH-values of feed phases (5.2 and 3, respectively). The proposed models offer good concordance with the experimental data and can be useful for facilitated pertraction optimization.     

Mathematical model for swelling in a liquid emulsion membrane system

Application of the liquid emulsion membrane (LEM) technology to the industrial scale is hindered by the challenges imposed by stability of the emulsion during the transfer of the solute (pertraction). One of the important factors which leads to the instability is swelling. Emulsion undergoes swelling due to the osmotic gradient across the membrane as well as due to the occlusion of the external phase into the membrane phase; the latter is caused by the hydrodynamic deformation of the membrane globules. In the present work, we have studied swelling of the emulsion phase in a water-in-oil-in-water type LEM system. Nitric acid is the internal aqueous phase and is encapsulated in organic membrane phase composed of DEHPA–kerosene-SPAN80. Demineralised water is used as the external phase. The effect of the composition of the system and the hydrodynamic condition on the rate of swelling has been studied. A mathematical model has been developed to describe the effects of the relevant parameters on swelling of the emulsion. The globules of the emulsion are viewed as having a core-shell structure, based on the visual evidence. The model takes into account both the osmotic and the occlusion modes of swelling and also the leakage of the internal phase. The predictions of the model are found to be in good agreement with the experiments. The model would be useful for evaluating the rate of pertraction of a solute through the membrane–strip combination used in the present study. The study would also be useful for tuning the design and the operating parameters in LEM pertraction to achieve minimum swelling of the emulsion.     

Development of Liquid Membrane Pertraction for the Removal and Recovery of Chromium from Aqueous Effluents

Abstract

Liquid membrane pertraction combines the loading and stripping steps of solvent extraction into a single unit operation, allowing the continuous removal and concentration of a given species. In this paper the feasibility of applying liquid membrane pertraction to the recovery of chromium (Cr(VI) from aqueous effluents with the objective of reducing levels to below allowable discharge limits has been examined. A continuous laboratory-scale liquid membrane pertractor was constructed to solve a variety of problems associated with the treatment of Cr(VI)-bearing streams. Various operational factors such as feed velocity, strip velocity, membrane velocity, and composition of the inlet feed were then examined. Satisfactory continuous runs lasting up to 22 days were achieved. Chromium levels in synthetic waste could be reduced from 200–300 mg/L down to 1 mg/L, well within most allowable discharge limits. Experiments showed that the strip phase can be concentrated with inlet Cr(VI) concentrations of 2000 ppm Cr(VI), with indications that it should be possible at even higher concentrations.     

Fractionation of Carboxylic Acids Mixture Obtained by Succinic Fermentation using Reactive Extraction

Formic, acetic, and succinic acids have been selectively separated from their mixture obtained by A. succinogenes fermentation using reactive extraction with tri-n-octylamine (TOA) dissolved in three solvents with different polarities (n-heptane, butyl acetate, and dichloromethane) without and with 1-octanol addition. This technique allows recovering formic and acetic acids from the mixture, the raffinate containing only succinic acid. The extractant concentration and organic phase polarity control the selectivity of acids extraction. Thus, at pH = 1, the selectivity factor increased from 92, in the absence of 1-octanol; to 148, in the presence of this alcohol in organic phase. The corresponding optimum concentrations of TOA in the solvent were 30 and 50 g/l, respectively. The total separation of monocarboxylic acids from the mixture with succinic acid is possible by a multi-stage extraction process, adjusting the extractant concentration in each stage to that stoechiometrically needed for reactions with formic and acetic acids only. The addition of 1-octanol reduces the number of required extraction stages.     

Kinetics and Mechanism of Copper Transfer by Hydroxy-Oximes in Three-Phase Liquid Systems

Abstract

A model of copper-facilitated transport in a three-liquid-phase pertraction system is proposed. The model takes into account the diffusional transport of copper species (ions and complexes) in all three liquids as well as the kinetics of chemical reactions. The latter, according to the model suggested, occurs in narrow reaction zones: aqueous layers adjacent to the donor membrane and acceptor-membrane interfaces. Experiments were carried out in a two-compartment agitated diffusion cell with a bulk liquid membrane: a 5% (vol) solution of the commercial copper extractant LIX 860 in C₁₁-C₁₃ normal paraffins. The donor solution used contained 1 g/L copper and the acceptor liquid was a 4.5 N aqueous solution of sulfuric acid. On the basis of experimentally obtained pertraction curves and the model suggested, it was found that the overall rate of the process is controlled by the diffusion of copper ions in the donor phase as well as by copper-complex decomposition. By applying an optimization procedure, the mass transfer coefficients and the rate constants were evaluated under the experimental conditions of this study.     

Chiral separation by combining pertraction and preferential crystallization

This work describes the application of a hybrid two-step enantioselective separation process. As a first step, pertraction using supported liquid membranes provides an initial enrichment, while the following preferential crystallization delivers the enantiopure crystals as final product. Mandelic acid in water was studied as a model system. Using a suitable chiral selector, pertraction provides enrichments exceeding 10% and reaching up to 20% in the permeate phase, which was sufficient to allow for subsequent selective preferential crystallization. Based on the individual performances of pertraction and crystallization, overall yields and productivities are estimated. The calculated productivities are compared with values achievable in alternatively applicable chromatographic separation processes using chiral stationary phases. The realized hybrid pertraction-crystallization process is in its present state for the example considered still inferior to preparative chromatography. Strategies for further improvement are suggested.     

LSER modeling of extraction of succinic acid by tridodecylamine dissolved in 2-octanone and 1-octanol

Reactive extraction can be used for the recovery of carboxylic acids from fermentation broth. Through the formation of complex with extractants at the two-phase interface, the carboxylic acids are partitioned into organic solvents. But, the recovery of carboxylic acids is interrupted by the conditions of fermentation broth. In this work, kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in 2-octanone and 1-octanol have been carried out. Equilibrium and kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in two functional groups (alcohol and ketone) such as 2-octanone and 1-octanol are reported. All measurements have been carried out at 298.15 K. The results of the liquid–liquid equilibrium measurements have been correlated by a linear solvation energy relationship – LSER model which takes into account physical interactions.     

Process intensification in extraction by liquid emulsion membrane (LEM) process: A case study; enrichment of ruthenium from lean aqueous solution

Process intensification in extraction as a unit operation can be realized through liquid emulsion membrane (LEM) process by combining extraction and stripping in one stage eliminating the need of stripper. LEM technique is very useful to enrich very lean aqueous phase containing precious metal to aid the recovery process. The technique is illustrated by applying the same to enrich platinum group noble metal, ruthenium (Ru) from its aqueous solution. The liquid membrane phase consisted of extractant (trioctylamine) dissolved in liquid paraffin modified with 1-octanol and the surfactant used was Monemul 80. The strip phase found to be very effective was perchloric acid. To facilitate extraction tin(II) chloride was added to the aqueous feed phase containing Ru at 20 ppm level. Various process parameters affecting the performance of LEM process such as extractant, surfactant, strip phase concentrations, the batch extraction time, the treat ratio and the speed of agitation were studied at bench scale to aid process development.     

Silver Recovery from Dilute Aqueous Solutions Using Semi‐Batch RF‐Pertraction

Silver recovery from dilute nitrate solution was studied by using a rotating film‐pertraction technique in a semi‐continuous mode. Tri‐isobutylphosphine sulphide (TIBPS) dissolved in kerosene was used as a carrier and an aqueous ammonia solution as a stripping phase. A high transfer flux of silver ions during the pertraction process was observed. It was shown that the selectivity of silver transport through the TIBPS‐containing liquid membrane provides an excellent separation of silver from other metals such as copper, nickel, and iron presented in the treated solutions.     

Study on creeping film pertraction. Recovery of copper from diluted aqueous solutions

Creeping film pertraction (CFP) is a new liquid membrane technique for simultaneous removal and concentration of dissolved species from their diluted aqueous solutions. A mobile organic membrane interposed between two creeping aqueous films, a donor (feed) solution and an acceptor (strip) liquor, selectively transports the specified species. CFP is a continuous mass transfer process in which eddy diffusion controls the mass fluxes in all three liquid films. A laboratory scale pertractor—CFP-50—was used to study the effects of principal process parameters on pertraction efficiency in the case of copper transport across a membrane of parafinic oil, containing 2% (vol.) commercial oxime extractant ACORGA P-5100 as carrier.     

Extraction and Liquid Membrane Preconcentration of Rosmarinic Acid from Lemon Balm (Melissa Officinalis L.)

Abstract

Liquid membrane separation technique was applied for the recovery and preconcentration of rosmarinic acid from aqueous extract of dried leaves of Balm lemon (Melissa officinalis L.). Among several studied organic solvents, diisopropyl ether and ethylacetate appeared to be appropriate membrane liquids for recovery and selective preconcentration of the acid. The difference in pH values between the two aqueous solutions was the driving force in this case. An integrated process coupling the extraction of rosmarinic acid from ground Melissa leaves with a simultaneous stripping of membrane and accumulation of the extracted solute was demonstrated using a laboratory bulk liquid membrane contactor. The process provided an almost complete (96 percent) exhaustion of the herbal mass and highly enriched final extract, containing 87 percent RA after strip solution drying.     

Effect of gold addition on Pt and Pd catalysts in liquid phase oxidations

Single phase Au–Pd and Au–Pt on carbon catalysts have been compared in the liquid phase oxidation of glycerol (representative for polyols) and n-octanol (representative for long chain aliphatic alcohol). The observed overall enhancement of catalytic activity appeared to be function of support, substrate and reaction conditions. Effect of substrate structure has been disentangled: synergistic effect between Au and Pt was maximized when polyol-like substrates were oxidized whereas Au–Pd based catalyst showed a more general match.     

Extraction of Platinum(IV) with Trioctylamine and its Application to Liquid Membrane Transport

Abstract

The extraction and stripping behavior of platinum(IV) between trioctylamine (TOA) in kerosene and different aqueous media has been investigated. Perchlorate anion was found to be most effective for the stripping of platinum under acidic and neutral conditions. The transport of platinum was performed through a supported liquid membrane (SLM) impregnated with TOA as a mobile carrier. Platinum was almost quantitatively transported from the hydrochloric acid solution to the stripping solutions containing perchlorate anion against its large concentration gradient without accumulation in the liquid membrane layer. The transport behavior of platinum was greatly improved by the addition of 1-octanol in SLM, and the permeation rate was mainly controlled by diffusion in the aqueous boundary layer.     

Liquid Pertraction or Liquid Membranes—State of the Art

Abstract

Liquid pertraction? or liquid membranes appeared as a prospective separation process relatively recently. Due to its obvious advantages over solid membranes and liquid-liquid extraction, liquid pertraction has attracted the attention of many scientists and engineers. At present there are more than 160 research teams around the world exploring this new, emerging separation operation.     

High-efficiency HFSLM for silver-ion pertraction from pharmaceutical wastewater and mass-transport models

Hollow fiber supported liquid membrane (HFSLM) is a favorable technique for the pertraction of metal ions, especially at very low metal concentration. In this work, the pertraction of silver ions from acidic pharmaceutical wastewater via HFSLM was investigated. Pharmaceutical wastewater containing 30 mg/dm³ of silver ions and 120 mg/dm³ of ferric ions was subjected to HFSLM as a feed solution. LIX 84-I dissolved in organic solvent together with Na₂S₂O₃·5H₂O solution was selected for use as a liquid membrane and a receiving solution, respectively. The influence of ferric ions on the pertraction of silver ions was studied firstly using wastewater with normal ferric ion concentration and secondly using wastewater with ferric ion precipitation by phosphoric acid solution. The highest pertraction of silver ions was achieved by using 0.1 M of LIX 84-I and 0.5 M of Na₂S₂O₃·5H₂O solution at pH of feed and receiving solutions of 3.5 and 2. The flow rates of feed and receiving solutions were 0.2 dm³/min. 0.6 mg/dm³ of silver ions that remained in the wastewater was below the mandatory discharge limit. No effect of normal ferric ion concentration in the wastewater on silver ion pertraction was observed. The crucial parameters were defined to confirm the efficiency and reliability of the system. Finally, the controlling transport regime of silver ion pertraction across HFSLM was determined by the diffusion flux and reaction flux models.     

Extraction of Nitric Acid into Alcohol: Kerosene Mixtures

Abstract

Nitric acid extraction from 0.1 mol/L – 5 mol/L nitric acid into varied volume fractions (5%–100%) of long-chain aliphatic alcohols (1-hexanol, 1-octanol, 2-ethylhexanol, 1-decanol) in alkanes (different kerosenes, n-dodecane, isooctane) was measured. At equal molar alcohol concentration, 1-hexanol, 1-octanol, and 1-decanol extract equal amounts of nitric acid. The amount of nitric acid extracted into 2-ethylhexanol is approxmately half compared to 1-octanol. The alkane does not influence nitric acid extraction. Extraction can accurately be calculated taking into account the formation of a species (HNO₃)(ROH)₂. Due to the change in diluent properties with alcohol volume fraction, conditional equilibrium constants must be used.     

Selective Recovery of Alkaloids from Glaucium Flavum Crantz Using Integrated Process Extraction-Pertraction

Abstract

Selective recovery of aporphine alkaloids from Glaucium flavum Crantz was studied. The alkaloids were successfully recovered from aqueous solutions, including native extracts of Glaucium flavum Crantz, applying pertraction in a rotating discs contactor. As a liquid membrane n-heptane and as receiving solution diluted phosphoric acid were used. Pertraction was also coupled to solid-liquid extraction in order to simultaneously purify the extract obtained from the plant. This integrated extraction-pertraction process was very simple, rapid, and efficient. The permeation of alkaloids through the liquid membrane was very selective and their purity in the receiving solution was 88.7%.