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《Journal of Coordination Chemistry》2012,65(13):2337-2348
An emulsion liquid membrane process using bis-(2-ethylhexyl) phosphoric acid (D2EHPA) to extract and separate Ni(II) and Co(II) from acidic chloride solutions is described. Liquid membrane consists of a diluent, a surfactant (Span 80), and an extractant (D2EHPA). Hydrochloric acid was used as the stripping solution. The important parameters governing the permeation of nickel and their effect on the separation process have been studied. These parameters are stirring speed, feed phase pH, surfactant concentration, extractant concentration, stripping phase concentration, phase ratio, initial concentration of metal, and treatment ratio. The optimum conditions have been determined. The separation factors of Ni(II) with respect to Co(II), based on initial feed concentration, have been experimentally determined. Furthermore, the extraction selectivity for Co(II) over Ni(II) has been improved by using D2EHPA during the initial minutes. 相似文献
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Sarah Chaouchi 《Journal of Dispersion Science and Technology》2014,35(9):1278-1288
This work aims to the extraction of the priority pollutant 4-nitrophenol (4-NP) from water by emulsion liquid membrane (ELM). Liquid membrane consists of a diluent (hexane) and a surfactant (Span 80). Sodium carbonate solution was used as internal aqueous phase. Effects of important experimental conditions governing the stability of the W/O emulsion were investigated. Influence of operating parameters that affects the permeation of 4-NP such as surfactant concentration, emulsification time, sulfuric acid concentration in external phase, acid type in external phase, internal phase concentration, type of internal phase, stirring speed, volume ratio of internal phase to membrane phase, treatment ratio, 4-NP initial concentration, and diluent type was examined. This study also evaluated the effect of Na2CO3 concentration in the internal aqueous phase on the stripping of 4-NP. Additionally, the reuse of the recovered membrane was studied. Under most favorable conditions, practically all the 4-NP and aniline (AN) molecules present in the feed phase were extracted. The recovery of the membrane phase was total and the extraction of 4-NP was not decreased. The ELM treatment process represents a very interesting advanced separation process for the removal of 4-NP and AN from aqueous solutions. 相似文献
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Emulsion liquid membranes (ELMs) can contribute to process intensification of zinc extraction, by significantly reducing the solvent and carrier requirements in comparison with conventional solvent extraction. Di(2-ethylhexyl)phosphoric acid (D2EHPA) was used as a highly selective carrier for the transport of zinc ions through the emulsified liquid membrane. The hollow-fiber extractor appears to offer significant advantages over conventional liquid–liquid contactors for this separation because emulsion leakage and swell are practically eliminated even when treating high concentration feeds. Various hydrodynamic and chemical parameters, such as variation in feed pH; zinc concentration in feed; variation in concentrations of D2EHPA; variation in feed/emulsion volume ratios and variation in feed and emulsion flow rates, were investigated. The content of sulfuric acid as an internal did not show in the studied range any significant influence on zinc extraction through the ELM, although a minimum hydrogen ion concentration is suggested in the internal aqueous solution to ensure acidity gradient between both aqueous phases to promote the permeation of zinc ions toward the internal phase. The experimental mass-transfer coefficients have shown a stronger dependence on hydrodynamic conditions in both the external feed phase and emulsion among the parameters studied. For emulsion flow rate, mass-transfer coefficient increased from 16.3 × 10−6 m/s at 200 ml/min to 31.2 × 10−6 m/s at 640 ml/min. Significant increasing in mass-transfer coefficient observed with increasing aqueous flow rate from 9.7 × 10−6 m/s at 170 ml/min to 37.2 × 10−6 m/s at 740 ml/min. The overall mass-transfer coefficient increases from 12 × 10−6 m/s at 2% D2EHPA to 28 × 10−6 m/s at 8% D2EHPA. This means that this process is chemically controlled and the interfacial resistance has a more significant role in the extraction of zinc by emulsion liquid membrane through hollow-fiber contactor. From the results obtained, it seems that the diffusion processes in aqueous feed phase and the membrane phase have the same importance as the chemical process. 相似文献
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This study aims to investigate the recovery of L-lactic acid from fermentation broth by an emulsion liquid membrane (ELM), made up of sunflower oil as the diluent, Sorbitan monooleate (Span 80) as the surfactant, Aliquat 336 as the carrier, and sodium hydroxide (NaOH) solution as the internal aqueous phase. Particularly, the ELM process was properly set up, through the identification of the optimal ELM operating parameters on the final extraction efficiency of L-lactic acid, including Span 80 concentration, NaOH concentration, Aliquat 336 concentration, stirring speed, phase ratio, and treatment ratio. The obtained results showed that the extraction efficiency of L-lactic acid reached up to 99% under the following optimal conditions: 10 minutes after contact time, 4% w/w Span 80, 3% w/w Aliquat 336, 0.1?N solution of NaOH, stirring speed of 300?rpm, phase ratio 1, and treatment ratio 0.25. A stable system without considerable emulsion swelling and breakage was monitored using a dynamic light scattering (DLS) apparatus for the selected optimal ELM operating parameters. 相似文献
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Multi-stage premix membrane emulsification for preparation of agarose microbeads with uniform size 总被引:1,自引:0,他引:1
Uniform-sized agarose beads with diameters less than 10 μm and agarose content as high as 14 wt% were prepared by premix membrane emulsification. Agarose aqueous solution was used as the water phase. A mixture of liquid paraffin and petroleum ether containing hexaglycerin penta ester (PO-500) was used as the oil phase. The water phase was mixed with the oil phase at 60 °C and a coarse W/O emulsion was produced in a homogenizer. Then, the coarse emulsion was extruded through a hydrophobic membrane under high pressure to form an emulsion, which was slowly cooled under gentle agitation to form gel beads. The effects of preparation conditions on emulsification results were investigated and it showed that the pressure, number of passes, petroleum ether/liquid paraffin (v/v) in the oil phase, the concentration of PO-500 and concentration of agarose in the water phase, all affected the size and uniformity; coarse emulsion did not affect the emulsification results. The coefficient variation (C.V.) of agarose beads under optimal preparation conditions was 9.8%. This method realized microbeads with both uniform sizes and high agarose contents that are difficult to be prepared by conventional emulsion methods. 相似文献
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本文先在大块液膜体系中以环已烷甲酸为载体,通过正交设计,系统地研究了各种因素对希土离子输送作用的影响规律。比较了相同条件下RE~(3+)(希土)同Na~+,NH_4~+、Ca~(2+)和Fe~(3+)等离子的输送作用。发现在适当条件下,无皂化的羧酸载体对RE~(3+)离子具有良好的输送效果,同时证实,羧酸输送RE~(3+)离子是通过三个H~+离子与一个RE~(3+)离子的交换,而当载体皂化时,皂化的载体直接与接收相H~+离子发生交换,从而降低了羧酸对RE~(3+)离子的输送和分离效果。 在大块液膜研究的基础上,建立了一个以无皂化的环烷酸为载体的乳状液膜体系,从模拟离子矿的硫酸铵浸出液中萃取希土,通过正交试验确定了最优的液膜萃取条件,希土萃取率达96%以上,富集度30~40倍。 相似文献
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乳状液膜法分离水中的铬 总被引:3,自引:0,他引:3
乳状液膜法由于其独特的物理化学性质,已广泛用于金属离子的萃取分离[1~3]。本文以span80-煤油-NaOH液膜体系分离水中铬。不加流动载体,利用内、外相中被分离物的浓度梯度实现物质迁移。当Cr2O2-7进入内相时,与内相的NaOH发生反应,在内相高浓度的NaOH存在下,可保持Cr2O2-7在液膜两侧有最大的浓度梯度,促使Cr2O2-7的迁移,实现Cr2O2-7与外相溶液的分离。1 实验部分1 1 仪器与试剂D40-1型电动搅拌器(杭州仪表电机厂),78-1型磁力加热搅拌器(江苏金坛新一佳仪器厂),721型分光光度计(上海第三分析仪器厂)。铬标准溶液(100ml/L):准… 相似文献
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本文用P204-兰113A-煤油组成的滤膜体系处理钒(Ⅳ)的溶液,并考察了表面活性剂、载体、外相pH值、内相酸度、起始钒(Ⅳ)浓度以及乳水比等因素对分离的影响。 相似文献
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S. M. Mousavi S. Kiani M. Razavi Farmad A. Hemati B. Abbasi 《Journal of Dispersion Science and Technology》2013,34(1):123-129
In this article, the extraction of arsenic(V) from water by means of emulsion liquid membrane is investigated. The influence of operating factors such as stirring speed, concentration of sulfuric acid in the external aqueous phase, concentration of sodium sulfate in internal stripping phase, and concentration of carrier in the membrane phase on the extraction efficiency are investigated and their optimum values, which provide the maximum recovery of arsenic, are determined. Taguchi experimental design is used in order to reduce the number of experiments. The optimum amounts for the extraction of arsenic from water, based on the results, are: stirring speed, 500 rpm; concentration of sulfuric acid in the feed, 1.5 g mol/lit; concentration of reagent in internal phase, 1.5 g mol/lit; and concentration of carrier in 3 ml kerosene which is added to the membrane phase, 0.1 g mol/lit. 相似文献
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Competitive permeation of alkali metal ions from an alkaline source phase into or through a toluene phase facilitated by the lipophilic crown ether carboxylic acid 2-(symdibenzo-16-crown-5-oxy)-decanoic acid is studied in liquid—liquid extraction, bulk liquid membrane transport, and emulsion liquid membrane transport. Most rapid transport was obtained in emulsion liquid membrane experiments. Some differences in selectivity orders for alkali metal permeation were observed for the three separation techniques. 相似文献
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Extraction of dioxins from blood samples was carried out by inclusion-facilitated emulsion liquid membrane process. The novelty of this work is the application of nano-baskets of calixarene and emulsion liquid membranes in the selective and efficient preconcentration of dioxin. For this aim, four derivatives of p-tert-calix[4]arene bearing different sulfonamide moieties were synthesized and their inclusion-extraction parameters were optimized including the calixarene's scaffold and concentration(as the carrier/demulsifier), the diluent type in membrane, the phase and the treat ratio, mixing speed, and initial solute concentration. Determinations were followed by a gas chromatograph and the results reveal that under the optimized operating conditions, the preconcentration of dioxins was improved and the method achieved lower limit of detections(LODs). Under optimal conditions, the figures of merits were determined to be LOD 1.0 pg/L, dynamic range 0.6―112.0 pg/L, RSD 5.5%(n=5), and the maximum enrichment factor and recovery were determined to be 3.3 and 99%, respectively. 相似文献
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Anil Kumar Parmjit Singh Panesar 《Journal of Dispersion Science and Technology》2018,39(10):1510-1517
A new stable green emulsion liquid membrane (GELM) was formulated by selecting the environmentally benign vegetable oils. The rice bran oil (RBO) based GELM has shown better stability in comparison to that obtained from other oils. GELM was prepared using 10?mL RBO, 0.25 [M] NaOH concentration, 2 (v/v, %) surfactant concentration, 0.4 (v/v) phase ratio, 2000?rpm emulsification speed, and 20?min emulsification time. Under these optimum conditions, GELM has been found to be stable for 120?±?2?min (no significant phase change) and has shown complete phase separation after 4 hours. Therefore, RBO as a green solvent has high potential to be applied in several ELM process applications. 相似文献
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用乳状液膜技术研究了从硼镁铁矿酸解中富集回收铀的工艺条件 ,对乳状液膜的组成及影响铀迁移率的主要因素进行了较详细的讨论 ,确定了富集铀的工艺参数。 相似文献
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《Journal of membrane science》1998,145(1):15-26
An experimental study on batch extraction of cephalexin using an emulsion liquid membrane system has been reported. The effects of surfactant, carrier and solute concentrations, phase volume ratio, stirring speed, and counterion concentration on the extraction rate were examined. Surfactant, carrier and diluent used were Span-80, Aliquat-336 and n-heptane–kerosene (1:1), respectively. Under the optimised experimental conditions, emulsion swelling was found to be marginal. By maintaining an appropriate pH gradient in the feed and receiving aqueous phase, facilitated transport could be realised. Selective separation of cephalexin from a mixture of 7-aminodeacetoxy cephalosporanic acid (7-ADCA) could be demonstrated in the emulsion liquid membrane system. A mathematical model based on mass transfer across aqueous boundary layer, interfacial chemical reaction and diffusion in the emulsion globule provides a reasonable fit of the experimental solute concentration versus time profiles in the emulsion liquid membrane system. 相似文献