Efficient transport and selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process using Aliquat 336 via HFSLM

The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants, i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently. The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol.     

Synergistic Solvent Extraction and Transport of Zn(II) and Cu(II) across Polymer Inclusion Membranes with a Mixture of TOPO and Aliquat 336

Separation of zinc(II) and copper(II) ions from aqueous solutions by synergistic extraction and transport through polymer inclusion membranes (PIMs) has been investigated. A mixture of trioctylphosphine oxide (TOPO) and trioctymethylammonium chloride (Aliquat 336) was used as a selective extractant as well as an ion carrier in polymer membranes. The effects of hydrochloric acid concentration in the aqueous phase and extractants concentration in the organic phase on the separation process of zinc(II) and copper(II) ions have been studied. Zn(II) ions were successfully separated from Cu(II) ions in solvent extraction process using 0.025 M TOPO and 0.06 M Aliquat 336 in kerosene. Polymer inclusion membranes (PIMs) containing a mixture of TOPO and Aliquat 336 as the ion carrier have been prepared and the facilitated transport of Zn(II) and Cu(II) ions has been studied. The influence of membrane composition on the transport kinetic of Zn(II) and Cu(II) has been evaluated. Zn(II) ions were preferably transported from the aqueous solutions containing Cu(II) and above 87% of Zn(II) ions were effectively recovered from the 0.5 M HCl solution as the source phase through PIM into 0.5 M H₂SO₄ as the stripping phase.     

Studies on Transport of Anionic Complex of Plutonium From Nitric Acid Medium across ALIQUAT 336/n-Paraffin Liquid Membrane

The present studies deal with the application of the supported liquid membrane (SLM) technique for the separation and purification of plutonium from other impurities in nitric acid medium using anion exchanger Aliquat 336 (a quaternary ammonium salt)/ n-paraffin as a carrier. The effects of feed acidity, stripping agent, and membrane pore size and membrane thickness on the transport behavior of anionic complex of plutonium have been studied in detail. An attempt has been made to establish the mechanism for plutonium transport and model the physicochemical transport of plutonium across SLM. Transport of anionic complex of plutonium increased with increase in carrier concentration upto 10% (w/v), while with further increase in carrier concentration, decrease in transport of plutonium was observed. The PTFE membrane with 0.45 µm pore size and 80 µm thickness was found to be most suitable for the transport of plutonium. The effect of membrane thickness indicates that the transport phenomenon is diffusion controlled. Transport behavior of plutonium, uranium, and other fission products from actual feed solution of ion exchange method obtained in PUREX process was also tested and the result clearly indicates that Aliquat 336 has high selectivity for plutonium and it can be used for the separation and purification of plutonium by the supported liquid membrane technique.     

Vanadium Extraction using Pseudo-Emulsion Based Hollow-Fiber with Strip Dispersion Technique

The present work investigated the removal rates of vanadium (V) from aqueous solution using PEHFSD technology. A pseudo-emulsion was prepared by dispersing hydrochloric acid (stripping) solution into an organic phase constituted of kerosene, Aliquat 336(carrier), and 1-decanol. Within 60 min, typical results with continuous recycling of both the feed and the pseudo-emulsion employing carrier concentration of 0.025 M and feed pH 5 showed that extraction was nearly 99% whereas maximum recovery in the HCl solution achieved was over 85%. Mathematical analysis suggested that the removal rates are controlled by mass transfer resistance from extraction and stripping reactions.     

Selective Separation of Gallium from Acidic Leach Solutions by Emulsion Liquid Membranes

Abstract

The separation and concentration of gallium from acidic leach solutions, containing various other ions such as iron, cobalt, nickel, zinc, cadmium, lead, copper, and aluminium, by an emulsion liquid membrane (ELM) technique using tributyl phosphate (TBP) as carrier has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (TBP), and 0.1 M HCl or 0.1 M H₂SO₄ were used as the stripping solution. The important variables governing the permeation of gallium and their effect on the separation process have been studied. These variables were membrane type and composition, mixing speed, diluent type, surfactant concentration, extractant concentration, HCl concentration in the feed, acid type of stripping phase, feed concentration, and treatment ratio. The optimum conditions were determined. It was possible to selectively extract 96.0% of gallium from the acidic leach solutions, containing Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, at the optimum conditions.     

Studies on the Recovery of Uranium from Phosphoric Acid Medium by D2EHPA/n-Dodecane Supported Liquid Membrane

Abstract

Present studies deal with the application of supported liquid membrane (SLM) technique for the separation of uranium (VI) from phosphoric acid medium using Di-2 ethyl hexyl phosphoric acid (D2EHPA)/n-dodecane as a carrier and ammonium carbonate as a receiving phase. The studies involve the investigation of process controlling parameters like feed acidity of phosphoric acid, carrier concentration, stripping agents, and the effect of thickness and the pore size of the membrane. The transport of uranium decreases with increase in the concentration of phosphoric acid in feed solution whereas it increases with increase in carrier concentration in supported liquid membrane. More than 90% uranium (VI) is recovered in 360 minutes using 0.5 M D2EHPA/dodecane as carrier and 0.5 M ammonium carbonate as stripping phase from the 0.001 M H₃PO₄ feed. Lower concentration of phosphoric acid and higher carrier concentration is found to be the most suitable condition for maximum transport of uranium (VI) from its lean sources like commercial phosphoric acid and analytical wastes generated from the analysis of uranium by Volumetric (Davis-Gray) method.     

One-through selective separation of copper,chromium and zinc ions by hollow fiber supported liquid membrane

The separation of a mixture of Cu(II), Cr(VI) and Zn(II) simultaneously from a sulfate media using two consecutive hollow fiber microporous liquid membrane extraction systems has been studied. The experiments were made in the one-through mode. LIX84-I and Aliquat336 were used as carrier extractants for copper and chromium in the first and second hollow fiber modules, respectively. Pure copper and pure chromium ions are extracted and stripped from first and second hollow fiber modules, respectively, but zinc ions cannot be extracted by both extractants due to pH conditions used in this study and remain in the raffinate. Results indicate that the percentage of extraction is highly dependent on pH of the feed solution and the pH value is 2.5 for the maximum extraction. The percentage of extraction of copper and chromium ions is enhanced when the concentration of LIX84-I and Aliquat336 is increased of which both maximum value is 0.5 M, and these results also occur in stripping phase. The influence of sulfuric acid and sodium hydroxide concentration in strip solution of each column was examined, and it was found that the percentage of extraction and stripping is further increased due to the difference of driving force. The maximum percentage of extraction for copper is 33% and 92% for chromium. The experimental results indicated the feasibility of separation and recovery of these metals from the dilute solution by using membrane technology     

Investigation of electrospun and film‐cast PVC membranes incorporated with aliquat 336 for efficient Cd extraction: A comparative study

This article was aimed to investigate the cadmium extraction behaviors of the two different polyvinyl chloride membranes incorporating Aliquat 336—electrospinning and film‐casting. An optimal investigation condition for membranes used in the extraction process was produced at 25 kV with 10 cm tip‐to‐collector distance. Membranes were electrospun for 8 h at 200 μL/h. Membrane extraction studies were carried out using a 127 mg/L Cd(II) solution. Scanning electron microscope (SEM) images revealed differences in fiber diameters and membrane morphology. The addition of Aliquat produced very fine fibers (7–722 nm) resulting Brunauer‐Emmett‐Teller (BET) surface areas of 4.67–11.3 m²/g for electrospun membranes and 1.70–5.44 m²/g for film‐casted membranes. Extraction studies using membranes with different levels of Aliquat (0–40% w/w) revealed that the cadmium extraction performance of electrospun membranes was significantly better than conventional film‐cast membranes. For 40% Aliquat 336, with an initial concentration of 127 mg/L Cd, the cast membrane extracted down to concentration to 115 mg/L as compared to electrospun membrane, which extracted down to 88 mg/L within 40 h. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synergistic strippants of Pd (II) ions in the presence of chloride medium from wastewater of electroless plating process via solvating system: Kinetics and thermodynamics study

ABSTRACT

Synergistic strippants of palladium complex with Trialkylmethylammonium chloride (Aliquat 336) has been investigated. Results show that synergistic strippants of thiourea and HCl can enhance the palladium stripping efficiency from the loaded Aliquat 336. Extraction of Pd (II) ions is sensitive to the concentration of extractant and chloride medium. The partition coefficient ascertained from the model was fitted with an experimental value. Thermodynamics analysis showed that ΔH and ΔS values were obtained at 10.74 kJ/mol and 77.81 J/molK, respectively.     

Exploration of heavy metal ions transmembrane flux enhancement across a supported liquid membrane by appropriate carrier selection

Extraction capabilities of three kinds of carriers, Aliquat 336, Kelex 100 and LIX 54, for cadmium removal have been investigated in supported liquid membrane (SLM) systems. The maximum fluxes obtained using Aliquat 336, Kelex 100 and LIX 54 are 1.12×10^-9, 1.5×10^-10 and , respectively. Theoretical calculation of these three carriers’ extraction capabilities for cadmium in SLM systems using the quantum chemical computation method has also been carried out. The single point energy calculation results show that the energy changes in the complex formation process are in the order of Aliquat 336/Cd(II)>Kelex100/Cd(II)>LIX 54/Cd(II), with energy changes of -657.79, -329.19 and 96.32 kcal/mol, respectively. This indicates the quantum chemical computation supports the experimental results well and can be proposed as an effective tool for carrier selection in the SLM system. FTIR results also agree with the computational results quite well. Investigation on the influence of stirring rate and strippant on the cadmium flux reveals that a stirring rate of 400 rpm and the use of 1 mM EDTA as the strippant constitute the optimal experimental conditions. It was also found that cadmium flux is a function of feed concentration at the low concentration stage and the cadmium flux is enhanced by appropriate addition of certain anion into the feed.     

The extraction of lactic acid by emulsion type of liquid membranes using alamine 336 in escaid 100

The extraction of lactic acid from aqueous solutions through an emulsion liquid membrane containing Alamine 336 as carrier was investigated. The influence of mixing speed, diluent type, surfactant concentration, extractant concentration, feed solution pH, stripping concentration, phase ratio, and feed concentration were examined. Liquid membrane consists of a diluent (n‐heptane, toluene, kerosene, Escaid 100, and Escaid 200), a surfactant (Span 80) and an extractant (Alamine 336), and Na₂CO₃ were used as a stripping solution. It is possible to extract 91% of lactic acid from aqueous solutions using Alamine 336 in Escaid 100, as an extractant and a diluent respectively.     

Solvent Extraction Studies of Zinc and Cadmium with Aliquat 336-S in Aqueous Chloride Solutions

Abstract

New solvent extraction systems have been developed for the extraction of zinc and cadmium from aqueous chloride solution using Aliquat 336-S dissolved in the nonpolar solvents heavy aromatic naphtha and xylene as the extractant. Moderately high concentrations of the metalions (1 mg/ml zinc and 2 mg/ml Cd) can be extracted quantitatively from acid solutions with an equal volume of 5% Aliquat 336-S solution in 15 sec. Both zinc and cadmium can be stripped from the organic phase with a series of aqueous stripping solutions. When comparing zinc and cadmium, cadmium is the easier to extract and the more difficult to strip under the same experimental conditions.     

Extraction of Hexavalent Chromium from Aqueous Stream by Emulsion Liquid Membrane (ELM)

Emulsion Liquid Membrane (ELM) separation technique is an effective procedure for the removal of Chromium (VI) ions from the wastewater stream. In the present study, the effect of changes of different parameters such as the pH of feed solution, the stirring speed, and the emulsification time, carrier concentration, surfactant concentration, the effect on the presence of other metal ions, are systematically investigated. The membrane phase consists of kerosene with hexane as diluant, Aliquat 336 as extractant, sorbitan mono-oleate (span 80) as surfactant. 1 (N) Sodium hydroxide is the stripping solution. Results show that by the ELM process, 90% Cr(VI) can remove successfully in optimum condition from feed.     

The extraction of platinum from Pt(II) chloride solution by a quaternary ammonium compound

The fundamental aspects of the extraction and stripping of platinum (II) from its chloride solution by Aliquat 336 diluted with toluene have been studied. The extraction and stripping was at 99.5 and 97.6% equilibrium within 30 s and 20 min respectively. The percentage extraction increased slightly with decreasing hydrochloric acid concentration. In 0.1 mol dm^?3 hydrochloric acid, 1.0 volume percent Aliquat 336 in toluene could load 9.8 mmol dm^?3 of platinum (II). The percentage stripping of platinum (II) from Pt(II)-load organic solvent increased with increasing sodium bisulphite concentration. The enthalpy changes of extraction and of stripping were 12.8 and 114.9 kJ mol^?1 respectively. Both of the reactions were endothermic.     

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.     

Transport of mercury(II) ion through a supported liquid membrane containing a triisobutylphosphine sulfide (Cyanex 471X) as a mobile carrier

Carrier‐facilitated transport of mercury(II) against its concentration gradient from aqueous 0.1 mol dm^?3 hydrochloric acid solution across a flat‐sheet supported liquid membrane (SLM) containing triisobutylphosphine sulfide (Cyanex 471X) as the mobile carrier in kerosene as diluent has been investigated. Dilute sodium thiocyanate solution (0.11 mol dm^?3) was the most efficient stripping agent among several aqueous reagents tested. Various parameters such as stirring rate, concentration of HCl in the feed solution, concentration of NaSCN in the strippant, concentration of Cyanex 471X in the membrane, and contact time were investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is about 100% after 6 h. The carrier, Cyanex 471X, selectively and efficiently transported Hg(II) ions in the presence of other associated metal ions. The method has been demonstrated to recover selectively mercury from waste samples and mercurochrome solution. © 2002 Society of Chemical Industry     

Mass transfer of cadmium ions in a hollow-fiber module by pertraction

The facilitated transport of Cd(Il) ions through a hollow-fiber-supported liquid membrane with bis-2-ethylhexyl phosphoric acid as carrier was studied. The mass transfer rate, expressed as permeability P, was measured as a function of mean aqueous solution velocity and carrier concentration. Characteristic ion permeabilities of 10-26 × 10⁻⁷ m/s were measured at feed velocities between 1 × 10⁻²−19 × 10⁻² m/s at stripping velocities between 0.22 × 10⁻²−7x 10⁻² m/s with constant feed flow. The measured permeabilities were compared to generally accepted mass transfer correlations. The predicted permeabilities adequately fit the experimental data, indicating that the rate limiting step in the transport of the ion was the diffusion through both aqueous films, feed and stripping, whereas the organic resistance of the membrane was negligible. Furthermore, the proposed model allowed the prediction of the permeability of cadmium for different experimental conditions, which is useful to perform experiments to reduce metal levels in water or other effluents.     

Facilitated Transport of Cadmium Ions from Hydrochloric Acid Solutions through a Liquid Membrane Containing Dicyclohexyl‐18‐Crown‐6 as Extractant‐Carrier

Abstract

The transport of cadmium ions from hydrochloric acid solutions across a bulk liquid membrane by using dicyclohexyl‐18‐crown‐6 (DC18C6) dissolved in dichloromethane has been studied at 25°C. The effect of the fundamental parameters influencing the transport, e.g., hydrochloric acid concentration in the feed phase, DC18C6 concentration and the type of diluent used in the membrane and time of transport have been investigated. The transported amount of the cadmium ions (initial concentration 0.001 M) from a 6 M hydrochloric acid solution across a dichloromethane solution of DC18C6 (0.05 M) into distilled water (receiving phase) was found to be 98.3 (±1.8) percent after 6 h. The selectivity and efficiency of the method toward cadmium ions were tested by performing the competitive transport experiments on the mixtures containing Cd²⁺, Ni²⁺, Mn²⁺, Co²⁺, Zn²⁺, Pb²⁺, and Fe²⁺ ions. The best selectivity was found for the recovery of the cadmium ions from its mixture with Ni²⁺, Mn²⁺, Co²⁺, and Pb²⁺ ions. Thus, the method can be proposed for the application in cadmium recovery from the sources containing these ions such as spent rechargeable nickel‐cadmium batteries.     

Performance of hollow fiber supported liquid membrane on the extraction of mercury(II) ions

The extraction and recovery or stripping of mercury ions from chloride media using microporous hydrophobic hollow fiber supported liquid membranes (HFSLM) has been studied. Tri-n-octylamine (TOA) dissolved in kerosene was used as an extractant. Sodium hydroxide was used as a stripping solution. The transport system was studied as a function of several variables: the concentration of hydrochloric acid in the feed solution, the concentration of TOA in the liquid membrane, the concentration of sodium hydroxide in the stripping solution, the concentration of mercury ions in the feed solution and the flow rates of both feed and stripping solutions. The results indicated that the maximum percentages of the extraction and recovery of mercury ions of 100% and 97% were achieved at the concentration of hydrochloric acid in the feed solution of 0.1 mol/l, the concentration of TOA at 3% v/v, the concentration of sodium hydroxide at 0.5 mol/l and the flow rates of the feed and stripping solutions of 100 ml/min. However, the concentration of mercury ions from 1–100 ppm in the feed solution had no effect on the percentages of extraction and recovery of mercury ions. Thus, these results have identified that the hollow fiber supported liquid membrane process has high efficiency on both the extraction and recovery of mercury (II) ions. Moreover, the mass transfer coefficients of the aqueous phase (k _i ) and membrane or organic phase (k _m ) were calculated. The mass transfer coefficients of the aqueous phase and organic phase are 0.42 and 1.67 cm/s, respectively. The mass transfer coefficient of the organic phase is higher than that of the aqueous phase. Therefore, the mass transfer controlling step is the diffusion of the mercury ions through the film layer between the feed solution and the liquid membrane.     

Permeation study on the hollow-fiber supported liquid membrane for the extraction of Cobalt(II)

The transport of Co(II) through hollow-fiber-supported liquid membrane containing di-(2-ethylhexyl) phosphoric acid (D2EHPA) diluted in kerosene was examined. The mass transfer rate, expressed as permeability, P, focused on diffusion through the aqueous layer in the feed solution, the organic layer and the aqueous layer in the stripping solution. Experiments were performed as a function of aqueous feed solution velocity (100-500 ml/min), carrier concentration (0.1-20% v/v), aqueous stripping solution velocity (100-1,000 ml/min) and feed concentration (100-1,000 ppm) with 0.1 M HCl in the product phase. pH of the feed solution was 5.0. The measured permeabilities were compared to generally accepted mass transfer correlations. The validity of the prediction was evaluated with the experimental data, and the data were found to tie in well with the theoretical values. The model is the reported describing that the rate limiting step in the transport of the ion was the diffusion through both aqueous films, feed and stripping, whereas the organic resistance of the membrane was negligible. From this study, the model has good potential for the prediction of permeability of Co(II).