Application Of Liquid Emulsion Membrane Technique For The Removal Of Cadmium(Ii) From Aqueous Solutions Using Aliquat 336 As A Carrier (original) (raw)
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Emulsion Liquid Membrane for Cadmium Removal: Determination of Liquid Membrane Components
Journal of Physical Science, 2018
Removal of cadmium is very important as it is one of several harmful heavy metals commonly found in textile wastewater. This study focused on determination of emulsion liquid membrane (ELM) components for cadmium removal. Carrier, diluent and stripping selection was done by contacting feed phase (150 ppm cadmium) with organic solution at ratio of 1:1. Both solutions were mixed at 500 rpm for 24 h using magnetic stirrer, then the samples were allowed to settle and separate. The results of the study showed that in comparison with acid solution, basic solution containing trioctylamine (TOA), kerosene and NH 3 as the carrier, diluent and stripping agent, respectively provided the best performance for cadmium removal using ELM. In addition, the ordering of the extraction in terms of magnitude for the diluents was highly correlated with the polarity, solubility and viscosity. Low polarity and viscosity, and high solubility of the diluent are preferred.
Journal of the Brazilian Chemical Society, 2006
Foi estudada a extração de íons cádmio(II) a partir de soluções aquosas ácidas, usando, em uma cela de transferência sob agitação, uma membrana líquida em emulsão, (MLE) preparada pela mistura de querosene com D2EHPA (um ácido alquilfosfórico) como carregador móvel e Span-80 como surfactante. A membrana MLE permitiu transporte eficiente do metal, da solução de alimentação para o extrato de coleta em experimentos realizados a 25 ºC. As variáveis significativas no transporte de cádmio através da membrana foram a concentração do extrator e a quantidade de metal na solução alimentadora. A concentração de HCl como agente de coleta afetou somente a taxa inicial de extração do metal, mas não a extensão da extração. A quantidade de surfactante usada neste estudo estabilizou a membrana adequadamente, mas o uso de uma quantidade maior produziu uma menor taxa de extração inicial devido à resistência inferfacial mais alta. Os resultados experimentais sugerem a possibilidade de recuperação ou remoção de metais tóxicos de soluções aquosas diluídas em um extrator baseado em membranas líquidas emulsificadas. It is studied the extraction of cadmium(II) ions from acidic aqueous solutions using a stirred transfer cell-type emulsion liquid membrane (ELM) prepared by dissolving in kerosene, with D2EHPA (an alkylphosphoric acid) as mobile carrier and Span-80 as surfactant. The ELM allowed efficient metal transport from the feed solution to the stripping liquor in experiments carried out at 25 ºC. The significant variables on cadmium transport through the membrane were extractant concentration and metal content in the feed metal-donor solution. Concentration of HCl as stripping agent affected only the initial metal extraction rate but not the extraction extent. The surfactant content used in this study stabilized the membrane adequately, but the use of a higher content produced a smaller initial extraction rate due to higher interfacial resistance. The experimental results suggest the possibility of recovering or removing valuable or toxic metals from dilute aqueous solution in an extractor based on emulsified liquid membranes.
Cadmium removal from aqueous solutions by an emulsion liquid membrane
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999
The removal of cadmium ions from an aqueous solution by an emulsion liquid membrane system is demonstrated, and the parameters of the system are experimentally studied in order to optimize the process. The principal result of the present study is the experimentally based conclusion that the main resistance to mass transfer may lie at the outer oil-water interface. This is shown by demonstrating that the separation process is almost independent of the water to oil phase ratio of the inner emulsion, which controls the inner interfacial area for mass transfer as well as the effective thickness of the oil membrane.
Optimization of Cadmium Extraction by Emulsion Liquid Membrane with Response Surface Analysis
2015
In the present study, the analysis and optimization of the extraction of cadmium by emulsion liquid membrane process has been studied. The response surface methodology (RSM) was employed to identify the effect of emulsion liquid membrane parameters. These included the tri-octyl-phosphine oxide (TOPO) concentration, sorbitan monooleate (Span 80) concentration, internal sulfuric acid concentration, external/emulsion phase ratio, stirring time and external phase acidity (pH). A reduced quadratic model was found to best fit the experimental data. The model was employed to evaluate the optimum combination levels of emulsion liquid membrane process parameters. The results showed a statistically significant effect of TOPO, Span80, and internal sulfuric acid concentrations on the extraction percentage of cadmium. A statistically significant interaction was found between Span 80 and external/emulsion ratio, between TOPO and Span 80, and between TOPO and internal sulfuric acid. The analysis o...
— In the present work the process of extraction of cadmium, copper, zinc, and iron metal ions was studied using Emulsion Liquid Membrane (ELM) technique. Emulsion liquid membrane system depends on the preparation primary water-in-oil emulsion then emulsified the primary emulsion in water to produce double water-in-oil-in-water emulsion. Therefore three liquid phases will occurs: internal (receiving) phase, liquid membrane phase, and external phase. The internal and external phases are miscible with each other but separated by the membrane phase which is immiscible with both. The membrane was prepared by dissolving the extractant D2EHPA (di-2-ethylhexylphosphoric acid) used as a mobile carrier, and sodium dodecyl sulphonate, a surfactant, in kerosene. The internal (receiving) phase was prepared by dissolving sulfuric acid in water. The effect of variables: initial concentration of metal ions in the feed phase, surfactant concentration, carrier concentration, sulfuric acid concentration in the receiving (internal) phase, agitation time, volume ratio of the external feed phase to the primary water-in-oil emulsion, and pH of feed were studied on the percentage removed of metal ions in experiments carried out in a batch-type stirred vessel at 30 o C. The results showed that the percent removed of metal ions was in general increase with increasing of surfactant concentration, carrier concentration, sulfuric acid concentration in the internal phase, agitation time, and pH of feed and decrease with the volume ratio of the external feed phase to the primary water-in-oil emulsion. The results show that it is possible to recover 98 % of metal ions mixture.
Application of Liquid Emulsion Membrane
—In the present work, emulsion liquid membrane (ELM) technique was applied for the extraction of cadmium(II) present in aqueous samples. Aliquat 336 (Chloride tri-N-octylmethylammonium) was used as carrier to extract cadmium(II). The main objective of this work is to investigate the influence of various parameters affected the ELM formation and its stability and testing the performance of the prepared ELM on removal of cadmium by using synthetic solution with different concentrations. Experiments were conducted to optimize pH of the feed solution and it was found that cadmium(II) can be extracted at pH 6.5. The influence of the carrier concentration and treat ratio on the extraction process was investigated. The obtained results showed that the optimal values are respectively 3% (Aliquat 336) and a ratio (feed: emulsion) equal to 1:1.
Extraction of Cadmium(II) by Supported Liquid Membrane Using TOPS99 as Mobile Carrier
Separation Science and Technology, 2002
The permeation rate of Cd(II) from a dilute aqueous sulfate media using supported liquid membrane technique has been studied. The microporous polypropylene film celgard 2500 was used as solid support for the liquid membrane and TOPS-99 was used as mobile carrier. Effect of different parameters such as stirring rate, Cd(II) concentration in feed solution, pH of feed solution, extractant concentration in membrane phase, and acid concentration in strip solution on cadmium flux was studied. It was observed that stirring speed of 500 rpm was sufficient to minimize the resistance due to aqueous boundary layer. Cadmium flux, J Cd(II) increases with increase in pH of feed solution from 3.0 to 6.0 as well as with increase of cadmium concentration in feed solution. Also with increase in TOPS-99 concentration in membrane phase up to 100 mol/m3 J Cd(II) increases and then becomes constant.
Industrial & Engineering Chemistry Research, 2008
E-waste management via liquid emulsion membrane (LEM) process for the extraction and enrichment of cadmium(II) has been studied using di-2-ethylhexyl phosphoric acid (D2EHPA) dissolved in n-dodecane as carrier and methane sulfonic acid (MSA) as a strip phase. The complexation stoichiometric coefficient (n) and equilibrium constant (K ex) were determined by carrying out conventional liquid-liquid extraction studies. The factorial design method was used to see the importance of parameters. Emulsion preparation parameters such as carrier concentration, surfactant concentration, and internal strip phase (MSA) concentration were determined to get maximum extraction and enrichment. The influence of operating process parameters on the performance of LEM process, i.e., residence time, speed of agitation, and treat ratio, has been studied. A realistic simple model to aid the process design of LEM process has been developed.
Review on solvent extraction of cadmium from various solutions
Hydrometallurgy, 2000
Cadmium has wide application in the manufacturing of alloys, batteries, pigments and metal plating. The solid and liquid waste is generated during the production and at the end of service life. The recovery and recycling of cadmium from these waste materials is necessary to gain the metal values and protect the environment from hazard. In hydrometallurgical processes, solvent extraction is an important process for the recovery of non-ferrous metals from different aqueous leach liquor and waste effluent/solutions. In present paper, the solvent extraction processes for the extraction and recovery of hazardous metal cadmium from aqueous solutions associated with commonly metallic and non-metallic ions, such as sulfate, chloride, nitrate and phosphate have been reviewed. Different process parameters, viz. pH, organic- to -aqueous ratio, kinetics of extraction and stripping to establish the conditions required for the extraction of cadmium and formation of a complex in the organic phase from different solutions, have been reported. The studies show the possibility of extraction and separation of cadmium from different solutions containing other metallic ions using anionic, cationic, solvating or mixed extractants. However, further attempts are also being made to develop selective organic extractants to recover cadmium efficiently on a commercial scale. The findings of these studies are also reported.► SX is potential tool for separation/ purification of Cd from aq. solutions. ► Based on solution composition, the extractant or mixed extractants can be selected. ► Cyanex 302, Cyanex 923, PC 88A and D2EHPA are found effective. ► D2EHPA has commercial potential for extracting Cd from solution.