Separation study of cadmium through an emulsion liquid membrane using triisooctylamine as mobile carrier

A study of the transport of Cd(2+) ions through a triisooctylamine (TIOA)-sorbitan monooleate (Span 80)-dimethylbenzene liquid membrane has been performed with varying concentrations of HCl, KI, TIOA, Span 80 and NaOH in the feed, membrane and stripping solutions. Maximum transport was observed with 0.025 M HCl, 0.01 M KI, 0.02 M TIOA, 3% (w/v) Span 80 and 0.05 M NaOH. With this system cadmium could be completely separated with Cu(2+), Zn(2+), Fe(2+), Co(2+), Ni(2+), Mn(2+), Cr(3+) and Al(3+). The transport mechanism of this metal ions through the membrane has been discussed.     

正十六胺为载体的乳状液膜迁移分离汞(Ⅱ)

以正十六胺为载体的乳状液膜迁移分离汞 的结果表明,当膜组成为(0 02～0 030)ｍｏｌ/Ｌ正十六胺+3%(Ｗ/Ｖ)Ｓｐａｎ80+煤油;内相为(0 010～0 020)ｍｏｌ/ＬＮａＯＨ;外相为0 020ｍｏｌ/ＬＫＣＬ+(0 010～0 10)ｍｏｌ/ＬＨＣｌ能使汞快速有效的完全迁移;并使Ｈｇ 与Ｃｕ ,Ｆｅ ,Ｚｎ ,Ｃｏ ,Ｎｉ ,Ｍｎ ,Ｐｂ ,Ｃｄ 等离子完全分离。不使用有毒害的膜溶剂甲秦或二甲苯[1-4],使用长碳链的有机胺,因而在相分离过程中避免了三相乳化现象。1.实验部分在制乳器中加入一定量Ｓｐａｎ80和正十六胺的煤油溶液,在约2000ｒ/ｍｉｎ转速下,加入内相试剂…     

以TTA—TBPO为协同流动载体的液膜法富集钪(Ⅲ)

提出用TTA-TBPO为协同流动载体的乳状液膜分离它集抗（Ⅲ）的方法。其最佳液膜体系的组成为4％Span80.5％TTA、3％TBPO、4％液体石蜡、84％煤油和内相水溶液（4mol/L），最优实验条件，提取钪（Ⅲ）的外相试液为pH=1．3～2．3，Roi（油内比）为1：1，Rew（乳水比）为20：100。本法用于分离富集稀土元素中的微量钪（Ⅲ），其回收率可达99．1％以上，相对标准偏差为3．5％以下，结果十分满意。     

Extraction and carrier mediated transport of urea using noncyclic receptors through liquid membrane systems

Extraction and carrier mediated transport through bulk liquid membrane and supported liquid membrane systems have wide applications in separation technology. This paper highlights the use of six noncyclic receptors (podands) having variations in chain length and end group for the removal of urea using liquid membrane system. These receptors R_1, R_2, R_3, R_4, R_5, R₆ are diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, diethylene glycol dibenzoate, diethylene glycol, triethylene glycol and tetraethylene glycol respectively. The sequence of extraction and transport of urea by BLM system using various receptors is R₂ > R₃ > R₁ > R₄ > R₅ > R₆ and R₆ ≈ R₃ > R₅ > R₄ > R₁ > R₂ respectively. Receptor R₂ containing butyl end group is best extractant while receptor R₆ with flexible backbone is best carrier and this carrier efficiency is used to remove urea using BLM system from the feed phase by recyclization process up to 88.16%. The experimental results influenced by concentration of receptors and urea. Effect of time was also studied.     

Pertraction of strontium in bulk liquid membrane systems using crown ether as a carrier

The rate of pertraction of Sr²⁺ by 18-crown-6 (18-C-6) ether and picric acid in bulk liquid membrane systems containing various surface-active substances depends not only on the concentration of 18-C-6 and picric acid but also on the presence of various surface-active substances.     

Gas permeability of high-temperature-resistant silicone polymer-vycor glass membrane

A high-temperature-resistant heterogeneous poly (dimethyl siloxane) membrane was prepared in situ by using monomer gas-phase polymerization in microporous media without employing prepolymerization. The permeation rates for various gases were measured at penetrant pressure up to 233 cmHg and at temperatures between 20°C and 200°C. The permeation rates for low-soluble gases, such as He, H₂, N₂, CO, O₂, and Ar, increased with increasing temperature. On the other hand, the permeation rates for highly soluble gases, such as C₂H₄ and CO₂, decreased with increasing temperature. For all gases, the permeation rate increases or decreases linearly with the increase of temperature. The turning points were observed for all gases in the temperature range of 140-160°C. Permeation rates of most gases decreased with the increase of temperature above the turning point, excepting those of helium and hydrogen.     

Retention in liquid chromatography with multicomponent mobile phases: Relationship with binary systems

Summary Using the concept of an effective concentration a method is proposed for predicting retention in liquid chromatography with multicomponent mobile phases based on experiments with corresponding binary ones. The method is verified for normal and reversed-phase systems with ternary mobile phases and agrees closely with experimental data.     

Drop size prediction in liquid membrane systems

The design of separation equipment using liquid membranes requires predictive methods for the estimation of drop diameters of the dispersed liquid membrane “macrodrop”. Existing models for drop breakage in liquid-liquid systems underpredict drop diameters of liquid membrane macrodrops even after incorporating the effects of dispersed phase viscosity and hold-up. By considering that the microdroplets within a liquid membrane macrodrop cause a damping of induced drop oscillations arising from external turbulence, the recently proposed model of Calabrese et al. (1986) has been modified and the resulting model equations have been shown to predict drop diameters of both oil as well as water liquid membrane macrodrops reasonably well.     

Gas permeability of phosphatidylcholine impregnated in a porous cellulose nitrate membrane

Egg-yolk phosphatidylcholine (EPC) and dipalmitoyl phosphatidylcholine (DPPC) were impregnated in a porous cellulose nitrate membrane, and permeabilities of oxygen, nitrogen, and carbon dioxide through these composite-type membranes were measured. Gases are suggested to permeate across the membrane by an activated flow of the solution—diffusion type through the impregnated lipid matrix. The EPC-filled membrane shows higher permeability and smaller activation energy of permeation compared to the DPPCfilled membrane, which is ascribed to the higher mobility of fatty acid chains of EPC compared to those of DPPC.     

Ionic liquid as hollow fibre membrane carrier for extraction of fluoroquinolone antibiotics in milk coupled with high-performance liquid chromatography quantification

A new hollow fibre liquid phase microextraction technology with an ionic liquid as the carrier was developed to determine the fluoroquinolone antibiotics in milk. In this technology, a porous polypropylene hollow fibre was filled with aqueous ionic liquid and the extraction efficiency of different factors, such as the type of hollow fibre membrane carrier, the pH and ionic strength of the donor solution, the pH of the acceptor solution, the stirring rate and the extraction time, were investigated. The optimised extraction condition was: [OMim][BF₄] impregnated in the pores of the hollow fibre; 0.1?mol?L^?1 of Na₂HPO₄ (pH 11.0) as the acceptor solution was injected into the lumen of the hollow fibre; 0.1?mol?L^?1 H₃PO₄ (pH 5.0) was used as the donor solution; 600?rpm was selected as the stirring rate; 120?min was the optimum extraction time. The proposed method provided very high factors with 130-fold, 156-fold and 116-fold enrichment of ofloxacin, ciprofloxacin and enrofloxacin, respectively.     

Studies on the partitioning of actinides from high level liquid waste solution employing supported liquid membrane with Cyanex-923 as carrier

The present paper deals with the studies on the partitioning of actinides from high level liquid waste solution of PUREX origin employing supported liquid membrane technique. The process uses solution of Cyanex-923 in n-dodecane as a carrier with poly tetra fluoro ethylene support and a mixture of citric acid, formic acid and hydrazine hydrate as a receiving phase. Transport studies are carried out for ²⁴¹Am under different experimental conditions to optimize the transport parameters such as feed acidity, carrier concentration, effect of uranium, trivalent metal ion and salt concentration in the feed. Studies indicated good transport of actinides across the membrane from nitric acid medium. Under the optimized conditions the transport of ²⁴¹Am is studied from a uranium depleted synthetic PHWR-HLLW and finally the technique has been used for the partitioning of alpha emitters from an actual research reactor-HLLW. High concentration of uranium in the feed is found to retard the transport of americium, suggesting the need for prior removal of uranium from the waste.     

Continuous flow liquid membrane extraction: a novel automatic trace-enrichment technique based on continuous flow liquid-liquid extraction combined with supported liquid membrane

Combining the continuous flow liquid-liquid extraction (CFLLE) and supported liquid membrane (SLM) extraction, a novel aqueous-aqueous extraction technique that we termed continuous flow liquid membrane extraction (CFLME) is developed for trace-enrichment. The analyte was firstly extracted into the organic phase in the CFLLE step, then transported onto the organic liquid membrane that formed on the surface of the micro porous membrane of the SLM equipment. Finally, it passed through the liquid membrane and was trapped by the acceptor. Aspects related to CFLME were studied by using dichloromethane as liquid membrane, and sulfonylurea herbicides as model compounds. An enrichment factor of over 1000 was obtained when 10 μg l⁻¹ of MSM was enriched for 120 min by this technique. The drawbacks of only a few organic solvents can be selected as liquid membrane with a limited lifetime in SLM operation was overcome. In this CFLME method, almost all solvents that used in the conventional liquid-liquid extraction (LLE) can be adopted and the lifetime of liquid membrane is no longer a problem.     

Dysprosium pertraction through facilitated supported liquid membrane using D2EHPA as carrier

The pertraction of dysprosium (Dy) through a supported liquid membrane (SLM) system consisting of PTFE (polytetrafluoroethylene) support, D2EHPA (di-2-ethylhexyl phosphoric acid) dissolved in kerosene as membrane solution, and HNO₃ solution as stripping solution, was studied. The experiments were designed by the Taguchi method in order to investigate the effects of initial Dy concentration, feed phase pH, different stripping solution concentration, and D2EHPA concentration in the membrane phase on Dy pertraction. Optimal experimental conditions for Dy pertraction were obtained using an analysis of variance (ANOVA) (feed concentration: 130 mg L^?1, D2EHPA concentration: 0.90 M, feed phase pH: 5, stripping phase concentration: 2 M). In addition, the stability of the carrier in terms of its leaching from the membrane support was studied over a period of 6 days and was found to be satisfactory over that time.     

Immobilization of ionic liquid with polyelectrolyte as carrier

An all-purpose approach to immobilize ionic liquids onto solid supports is proposed by chemical grafting on a polyelectrolyte carrier.     

Selective transport of silver ions through bulk liquid membrane using Victoria blue as carrier

Transport of Ag⁺ as Ag(CN)₂⁻ ions through a bulk liquid membrane is reported. The bulk liquid membrane used is a solution of Victoria blue (VB) in chloroform. The effects of pH of the source phase, cyanide concentration in the source phase, sodium hydroxide in the receiving phase, and VB concentration in the organic phase on the efficiency of the transport system were studied. The above system has a high selectivity for Ag⁺ and can selectively and efficiently transport Ag(CN)₂⁻ ion from aqueous solutions containing other cations such as alkali and alkaline earths, Zn²⁺, Pd²⁺, Cu²⁺, Cd²⁺,Hg²⁺, Co²⁺, Fe²⁺, Pb²⁺, Ni²⁺, and Al³⁺.     

Supported liquid membrane extraction of W(VI) ions using tri-n-octylamine as carrier

Study of the extraction of W(VI) ions using supported liquid membrane has been carried out. The carrier used for this metal ion transport, is tri-n-octylamine (TOA) dissolved in xylene. The liquid was supported in microporous polypropylene film. The parameters studied are effect of carrier concentration in the membrane, acid concentrations in the feed solution, concentration of stripping agent on transport of W(VI) ions and of temperature on the transport properties of these supported liquid membranes. The optimum conditions of transport for these metal ions determined are, TOA concentration, 0.66 mol·dm^–3 (TOA); HF concentration in the feed solution, 0.01 mol·dm^–3 and concentration of NaOH used as stripping agent 2.5 mol·dm^–3. The maximum flux and permeability determined under optimum conditions are 3.06·10^–5 mol·m^–2·s^–1 and 8.44·10^–11 mol· ·m²·s^–1 at 25±2°C and 4.21·10^–5 mol·m^–2·s^–1 and 11.55·10^–11 mol·m²·s^–1 at 65°C, respectively. The diffusion coefficients for the metal ion carrier complex in the membrane have also been determined. Under the optimum conditions the value for the metal ion carrier complex is 0.14·10^–11 mol·m²·s^–1. Mechanism of transport and the complex formed in the presence of HF have also been discussed. The transport process involves two carrier amine molecules and two protons.     

Facilitated transport of palladium(II) across polymer inclusion membrane with ammonium ionic liquid as effective carrier

This work focuses on the application of polymer inclusion membrane (PIM) with tricaprylmethylammonium thiosalicylate, [A336][TS] (TOMATS), a thiol-containing task-specific ionic liquid for the transport of Pd(II) ions from aqueous solutions. 0.3 M thiourea in 0.1 M hydrochloric acid was found the most effective stripping phase in the transport of Pd(II) from membrane phase containing TOMATS. Separation of Pd(II) ions was also carried out from hydrochloric acid solution containing Pt(IV), Fe(III), Ni(II), and Mn(II). Pd(II) ions were preferably transported in the presence of these metal ions. The separation coefficients followed the order: S _Pd/Pt < S _Pd/Fe < S _Pd/Ni < S _Pd/Mn. [A336][TS] proved to be an excellent ion carrier for Pd(II) from hydrochloric acid solution. The results also showed that transport efficiency of the PIM was reproducible and it can be useful for the development of the simple and highly effective method of Pd(II) recovery from leach liquor of spent catalysts.