Pseudo-emulsion Based Hollow Fiber Strip Dispersion Research Articles

Mathematical Modeling of Extraction of Neodymium using Pseudo-emulsion based Hollow Fiber Strip Dispersion (PEHFSD)

Pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) is a promising alternative technique due to its stability, simplicity and cost of operation. This is an efficient process due to its high surface area for extraction as well as stripping, and low energy consumption for creating the pseudo-emulsion and for the separation of phases. This technique takes the combine advantages of emulsion liquid membrane and overcomes the sufferings of membrane stability in the supported liquid membrane systems. Present work includes extraction of neodymium (III) (Nd) by using TODGA and HNO3 as the extractant cum strippant in PEHFSD technique. A model is developed to study the transport of Nd under different hydrodynamic and chemical conditions that includes organic ratio (A/O) in dispersion, effect of speed of impeller on drop size formation, effect of feed acidity, effect of carrier concentration, effect of feed flow rate. A code is written to solve the model equations numerically to predict the concentration of the feed reservoir with time. Experiments are conducted to obtain the best optimum extraction conditions. Results obtained from the numerical simulations are validated with the experimental data and found a good agreement between them.

Zinc(II) recovery using pyridine oxime-ether – Novel carrier in pseudo-emulsion hollow fiber strip dispersion system

The recovery of zinc(II) from chloride solutions using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technique with a novel extractant was investigated. The pyridine oxime-ether, N-decoxy-1-(pyridin-3-yl)ethaneimine, was used as the carrier in the membrane. The influence of several parameters such as the flow rates, the composition of the feed phase, the composition of the membrane and type of strippant on the zinc(II) extraction was studied. The analysis of Zn(II) transport was made on the basis of the overall mass transfer coefficient of permeation, the values being found in the range of 2.1 × 10−7–3.4 × 10−6 m/s. The separation of Zn/Fe was also examined. The selectivity of the pyridine oxime-ether extractant over iron was compared with that of the classical extractant, tributyl phospate.

Recovery of zinc(II) from chloride solutions using pseudo-emulsion based hollow fiber strip dispersion with pyridineketoxime extractants

Abstract The recovery of Zn(II) from chloride solutions using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technique with pyridine reagents was investigated. The pyridineketoxime extractants were used as the carriers: 1-(3-pyridyl)undecan-1-one oxime and its quaternary salts 3-[1-(hydroxyimine)undecyl]-1-propylpyridinium bromide and 3-[1-(hydroxyimine)undecyl]-1-propylpyridinium chloride. The influence of several parameters, among them the hydrodynamic conditions, extractant, metal and strippant concentrations, as well as, the extractant structure on the zinc(II) extraction was studied. The surface properties of the various aqueous/organic systems and mass transfer resistances were also determined. The extractants proposed showed to be appropriate carriers in the PEHFSD process and the values of overall mass transfer coefficient of permeation were found in the range of 2.5 × 10 −7 –1.1 × 10 −6 m/s.

Mass Transfer and Immobilized Organic Phase Instability Studies for Cobalt(II)–Nickel(II) Separation by PEHFSD

Pseudo-emulsion-based hollow-fiber strip dispersion (PEHFSD) technique was examined as an alternative to solvent extraction for simultaneous separation and concentration of cobalt(II)–nickel(II) mixture using Cyanex-272 as the extractant. Experiments were carried out by continuous recirculation of the feed and pseudo-emulsion phases through a hollow-fiber module. The separation factor increased rapidly after 60 min of operation. The maximum value after 120 min of operation was ∼128 (pH = 6.5) for the operating conditions studied. The mass transfer resistance from the extraction reaction appeared to be dominant. The results of mathematical modeling of the mass transfer process indicated that higher separation factor and extraction rate can be achieved using PEHFSD in comparison to solvent extraction. Mixing of the stripping and the feed solution was observed at high dispersed phase volume fraction in the pseudo-emulsion and low flow rate of this phase. The maximum value of backtransport flux from the stripping phase due to mixing was estimated to be approximately two orders lower than the initial extraction rates.

Recovery of zinc(II) from chloride solutions using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) with 1-(3-pyridyl)undecan-1-one oxime or tributylphosphate

Abstract The recovery of zinc from chloride solutions using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technique was investigated. The novel extractant, 1-(3-pyridyl)undecan-1-one oxime, and a well-known one, tributyl phosphate (TBP), were used in the processes. The influence of several parameters, including the initial concentration of Zn(II) and sodium chloride in the aqueous phase and the type of extractant on Zn(II) extraction was studied. The Zn(II) transport was analyzed on the basis of the overall mass transfer coefficient of permeation. The oxime was shown to be a potential carrier of zinc from chloride medium, being a promising alternative to the classical extractant TBP.

Transport of Au(CN)2 − by Mixtures of Amine Primene JMT and Phosphine Oxide Cyanex 923 Using the Pseudo-Emulsion Based Hollow-Fiber Strip Dispersion Technology

The transport of Au(CN)2 − between alkaline aqueous solutions and organic phases consisting of a mixture of the amine Primene JMT and the phosphine oxide Cyanex 923 in xylene was studied using the pseudo-emulsion based hollow-fiber strip dispersion (PEHFSD) technology. The feed phase was passed through the lumen side, and the pseudo-emulsions of the extractant mixtures and NaOH were passed through the shell side in a countercurrent mode using a single hollow-fiber contactor for extraction and stripping. In this membrane technology, the strippant (NaOH solution) is dispersed in the organic (Primene JMT + Cyanex 923 in xylene) membrane solution in a tank with an impeller stirrer adequate to form strip dispersion. The pseudo-emulsion phase is circulated from the reservoir tank to the membrane contactor to provide a constant supply of the organic solution to the membrane fibers. Furthermore, this technology allows a direct contact between the organic and strip solutions, providing a greater area for stripping and facilitating the metal recovery from the strip solution once both phases are separated. Various hydrodynamic and chemical parameters, such as flow of feed phase, extractant mixtures and gold concentrations, organic diluents, variation in feed pH, and the selectivity of the system with respect to the transport of different metal-cyano complexes, were investigated. Aqueous and membrane mass transfer coefficients were estimated for the present system.

Membrane-based extraction with strip/organic dispersion methodologies for metals removal and recovery from wastewaters

Abstract The generation of liquid effluents containing organic and inorganic residues from industries presented a potential hazardousness for environment and human health, being mandatory the elimination of these pollutants from the respective solutions containing them. In order to achieve this goal, several techniques are being used, and among them, supported liquid membranes technologies are showing their potential for their application in the removal of metals contained in liquid effluents. Supported liquid membranes are a combination between conventional polymeric membranes and solvent extraction. Several configurations are used: flat-sheet supported liquid membranes, spiral wounds and hollow fiber modules. In order to improve their effectiveness, smart operations have been developed: pseudo-emulsion membrane based strip dispersion (PEMSD), pseudo-emulsion based hollow fiber strip dispersion (PEHFSD), hollow fiber renewal liquid membrane (HFRLM) and double strip dispersion hybrid liquid membrane (SDHL...

Cobalt(II) membrane-extraction by DP-8R/Exxsol D100 using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) processing

The transport of cobalt(II) from acidic sulphate solutions through PEHFSD was investigated using the extractant DP-8R in Exxsol D100. The acidic feed solution containing Co(II) was passed through the tube side, and pseudo-emulsions of DP-8R/Exxsol D100 and sulphuric acid was passed through the shell side in counter-current mode, using a single microporous hydrophobic polypropylene hollow fiber contactor for extraction and stripping. In PEHFSD the aqueous strip (sulphuric acid) solution was dispersed in the organic membrane solution in a reservoir tank with an impeller stirrer to form a strip dispersion. This pseudo-emulsion phase is circulated from the tank to the membrane module to provide a constant supply of the carrier solution to the membrane micropores. Several hydrodynamic and chemical parameters, such as variation in feed pH (3–7), cobalt concentration in feed (0.17–1.7 × 10 −3 M), carrier concentration (0.16–1.28 M), etc., were investigated. Mass transfer modelling was performed and the validity of the model was evaluated with experimental data. Moreover, the system was applied in the cobalt purification of synthetic lithium solutions derived from the processing of rechargeable batteries, with cobalt/lithium separation factor values around 25.

Nickel(II) removal by mixtures of Acorga M5640 and DP8R in pseudo-emulsion based hollow fiber with strip dispersion technology

This work presents the investigation of Ni(II) extraction from aqueous solution through pseudo-emulsion based hollow fiber strip dispersion (PSEHFSD) containing the mixture 2-hydroxy-5-nonylbenzaldehyde oxime + di(2-ethylhexyl) phosphoric acid/Exxsol D100 as extractant in the form of a pseudo-emulsion with H 2SO 4. The organic and aqueous strip phases are separated when the stirring device is stopped. The permeation of Ni(II) is investigated as a function of various experimental variables: hydrodynamic conditions, feed pH, extractants mixture concentration in the pseudo-emulsion, initial Ni(II) concentration in feed phase, H 2SO 4 concentration in the pseudo-emulsion as strippant. In PEHFSD, pseudo-emulsion is an emulsion that is formed temporarily between organic and stripping solutions. In this investigation, feed was circulated through the lumen side in counter-current mode. The selectivity of 2-hydroxy-5-nonylbenzaldehyde oxime + di(2-ethylhexyl) phosphoric acid/Exxsol D100 based PEHFSD toward different metals was also examined.

Pseudo-emulsion based hollow fiber with strip dispersion pertraction of iron(III) using (PJMTH +) 2(SO 42−) ionic liquid as carrier

The transport of iron(III) from acidic media using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technology is investigated. As a carrier, (PJMTH +) 2(SO 4 2−) ionic liquid, generated by direct reaction of the commercially available primary amine Primene JMT and sulphuric acid, is used. Several hydrodynamic conditions were investigated: concentration of iron (0.01–1 g l −1) and sulphuric acid concentration (10 −3–0.5 M) in the feed phase, carrier concentration (1–30%, v/v) and sulphuric acid concentration (1–3 M) in the organic and strip solutions, of the pseudo-emulsion phase. The values encountered for the membrane and feed resistances, 112 and 1000 s/cm, showed that the contribution of the membrane resistance is negligible, whereas the feed resistance contributes around 17% to the overall resistance value (near 5800 s/cm), thus, the interfacial resistances due to the extraction and stripping reactions appeared dominant. The performance of the system is also compared against other ionic liquids generated from available amine extractants (Primene 81R, Primene TOA, Amberlite LA2 and tridodecylamine) and other hollow fiber configurations.

Application of pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) for recovery of Cr(III) from alkaline solutions

The permeation of chromium (III) using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technology and the quaternary ammonium salt trioctyl methylammonium chloride (TOMACl) dissolved in n-decane as mobile carrier has been investigated. Factors affecting chromium permeability, such as hydrodynamic conditions, carrier concentration in the organic phase, metal and NaOH concentrations in the feed phase, etc., have been analyzed. The value of the overall permeation coefficient obtained under standard experimental conditions was 4.0 × 10 −4 cm s −1. Mass transfer modelling was performed and the aqueous and membrane resistances were estimated as 1066 and (1.7–17) × 10 3 s cm −1, respectively.

Pseudo‐emulsion based hollow fiber strip dispersion: A novel methodology for gold recovery

AbstractThis article presents the study of Au(I) extraction from synthetic cyanide media through pseudo‐emulsion based hollow fiber strip dispersion (PEHFSD) containing LIX‐79/n‐heptane as extractant in the form of a pseudo‐emulsion with NaOH. The permeation of Au(I) is investigated as a function of various experimental variables: hydrodynamic conditions, feed pH, LIX‐79 concentration in pseudo‐emulsion, cyanide concentration in feed phase, NaOH concentration in pseudo‐emulsion as a strippant, and initial Au(I) concentration in feed phase. In PEHFSD, pseudo‐emulsion is an emulsion that is formed temporarily between organic and stripping solutions. The organic and aqueous solutions are separated when the stirring device is stopped. In this study, feed was circulated through the tube side in counter current mode. The linear flow velocity of the feed was varied between 0.74 and 2.58 cm/s and the linear flow velocity of the pseudo‐emulsion was maintained at 0.28 cm/s. The value of the permeation coefficient obtained under standard experimental conditions was 8.19 × 10−5 cm/s. The selectivity of LIX‐79/n‐heptane based PEHFSD toward different metal cyanide salts such as Fe(II), Cu(I), Ni(II), Zn(II), and Ag(I) was also examined. © 2007 American Institute of Chemical Engineers AIChE J, 2008

Au(I) extraction by LIX-79/ n-heptane using the pseudo-emulsion-based hollow-fiber strip dispersion (PEHFSD) technique

The extraction of Au(I) from alkaline cyanide solutions through PEHFSD was conducted in a microporous hydrophobic polypropylene hollow-fiber membrane contactor. The organic extractant LIX-79 ( N, N-bis(2-ethyl hexyl)guanidine) in n-heptane was used. The alkaline cyanide feed solution containing Au(I) was passed through the tube side, and pseudo-emulsions of LIX-79/ n-heptane and NaOH were passed through the shell side in counter-current mode, using a single microporous hydrophobic polypropylene hollow-fiber contactor for extraction and stripping. In PEHFSD the aqueous strip (0.2 M NaOH) solution is dispersed in the organic (12% LIX-79/ n-heptane) membrane solution in a container with a mixing arrangement (impeller stirrer) designed to form a strip dispersion. The strip dispersion is circulated from the mixer to the membrane module to provide a constant supply of the LIX-79/ n-heptane solution to the membrane pores. Various hydrodynamic and chemical parameters, such as variation in feed pH; gold cyanide concentration in feed; variation in concentrations of NaOH, LIX-79/ n-heptane and Au(I); variation in feed, strip and LIX-79/ n-heptane volume ratios and variation in feed and strippant flow rates, were investigated. Mass transfer modeling was performed and the validity of the model was evaluated with experimental data and found to tie in well with theoretical values. It was possible to concentrate Au(I) in product (NaOH) using the PEHFSD technique.