Preparation of a Chelating Polymeric Membrane and Application to Uphill Transport

Abstract

Modification of an anion-exchange membrane by (1-(2-arsono-phenylazo))-2-hydroxy-3,6-naphthalenedisulfonic acid (thoron) results in a membrane that can chelate metals. The high affinity of the disulfonate for the anion-exchange sites together with molecular adsorption of the aromatic thoron onto the polymers yields a system that is stable in strong acids at or below 1 M. By employing a relatively high pH sample (5-9) in conjunction with an acidic stripping solution (0.2 - 1.0 M HCl), uphill transport of Cu(II) and Zn(II) was accomplished. The transport rate was increased by means (lower chelating capacity and the use of a chelate-forming aid on in the stripping solution) of promoting the volume diffusion mechanism of membrane transport. With a 0.05 mmol per dry gram chelating capacity and a 0.1 M EDTA stripping solution (pH 6.5), an enrichment factor of 16 was observed in a one-hour experiment with a 200 mL sample, 11 cm² membrane, and 5 mL stripping solution. This value compares favorably with those obtained by other uphill transport modes under the same conditions.     

Studies of Anion Transport Through Supported Liquid Membrane

Abstract

Transport studies of anions were investigated through cellulose triacetate supported liquid membrane. The experimental variables explored were concentration of anions, sodium hydroxide, and stirring speed. The two-channel membrane system has been explored for the transport of carbonate ions from source to receiving phases. Carbonate ions are selectively transported through the cellulose triacetate supported liquid membrane in comparison with that of nitrate and sulfate. Sulfate and nitrate anions are strongly held in the cellulose triacetate membrane, and then stripped out later. Carbonate ions are loosely bound to the cellulose triacetate membrane and stripped out earlier.     

Selective Transport of Saccharides Through a Liquid Membrane Using Cyclodextrin Dimer

A new effective transport system for saccharides through a liquid membranewas constructed. The transport rate of d-ribose in the condition of theliquid membrane with cyclodextrin dimer (2) as a transporter is 2.5 timerlarger than that without the transporter, whereas the transport rate of d-ribosein the condition of the liquid membrane with cyclodextrin monomer (1) isalmost the same as that without the transporter. The transport rate of methyld-glucoside by 2 is over twice than that by 1. The transport rate of d-deoxyribose by 2 is larger than that by 1.     

杯芳烃的超分子化学研究（IV）：对-叔丁基杯[4]芳烃对ATP的分子识别及液膜传输作用

采用气泡式准乳化液膜法 ,研究了对 -叔丁基杯 [4 ]芳烃对ATP分子的液膜传输作用 ,讨论了源相与吸收相的组成、酸度、源相中的ATP的起始浓度及吸收相中NH3 ·H2 O浓度等因素对传输结果的影响 ;进而讨论了对 -叔丁基杯 [4 ]芳烃对ATP的分子识别作用和液膜传输机理     

Facilitated Transport of Penicillin G by Bulk Liquid Membrane with TBP as Carrier

The facilitated transport of penicillin G from aqueous solutions to the stripping phase through bulk liquid membrane (BLM) containing TBP in 3% iso-octanol and n-butyl acetate was studied. Na₂CO₃ solution was used as the stripping phase. Experiments were performed as a function of stirring rate, TBP concentration and type of diluent in the liquid membrane phase, pH, and initial penicillin G concentration in the feed phase, Na₂CO₃ concentration in the stripping phase, etc. The results showed that the BLM process could carry out the simultaneous separation and concentration of penicillin G from dilute aqueous solutions, and arise “up-hill” effect due to the characteristic of non-equilibrium mass transfer. The diffusion of penicillin G complex in the liquid membrane phase played an important role in BLM process. The mass transfer mechanism of BLM for this system was also discussed.     

硒功能化杯[4]芳烃对金属离子的识别及在PVC基质支撑液膜的传输作用

提出以PVC为基质的支撑液膜传输体系，研究了以新研制的硒功能化杯[4]芳烃 为活性载体，邻苯二甲酸二辛酯（DOP）为膜溶剂的PVC基质支撑液膜对金属离子的 传输性能。采用双层夹心膜电位法测定了活动载体-金属离子在膜中的配合物生成 常数，对离子在膜中的传输速率、选择性系数以及生成常数之间的相关性作了研究 。使用该体系发现，在8种金属离子中汞具有最快的传输速率；进一步讨论了硒功 能化杯[4]芳烃对金属离子的识别作用和支撑液膜传输机理。     

杯[4]芳烃衍生物对Pb2＋的液膜传输动力学

以3类含不同基团的杯[4]芳烃衍生物作为离子载体在H2O-CHCl3-H2O液膜传输体系下分别对Pb2＋进行液膜传输实验. 简要讨论了以杯[4]芳烃衍生物作为离子载体对Pb2＋液膜传输的动力学机理. 重点研究了不同载体种类, 载体浓度, 搅拌速度, 传输时间等因素对Pb2＋传输的影响. 实验结果表明: 以含Br原子的杯[4]芳烃衍生物和含S原子的杯[4]芳烃衍生物作为离子载体对Pb2＋有明显的传输效果. 可以用本文的动力学模型来描述整个传输体系的动力学特性.     

杯芳烃衍生物液－液萃取和液膜传输银的对比研究及机理探讨

以4类含硫、硒、氮等杂原子基团二取代的杯[4]芳烃五衍生物（1－14）为中 性载体，在H2O-CHCl3-苦味酸体系萃取银和H2O-CHCl3-H2O液膜体系中传输银进行 了对比研究。萃取和传输结果具有一致性，除了苯并噻唑取代的杯[4]芳烃衍生物 （3－6）外，其它10个含硫、硒、氮的杯[4]芳烃衍生物1－14均对软重金属银和汞 有很高的选择性，而吡啶取代的杯[4]芳烃衍生物7－10对铅有一定的萃取选择性， 其中羟基硫醚取代的杯[4]芳烃衍生物11－14对银的萃取率和传输速率最大。并且 就杯[4]芳烃衍生物对银的传输机理进行了探讨，发现传输速率随源相中金属离子 浓度和有机相中载体浓度的增加而增大，因此推论这是由金属离子浓度梯度推动下 的传输。     

Assembly Synthesis of Sheet-like Calcite Array and Stable Vaterite by Supported Liquid Membrane

Sheet-like calcite array and stable vaterite were synthesized by bio-mimetic supported liquid membrane system under different reaction conditions. Both of the FTIR spectra of products showed narrower peak at 1418 cm^-1 than that of bulk CaCO3, and that of vaterite has a split in this peak.     

Supported Liquid Membrane Enrichment Studies of Natural Water Samples Applied to Liquid Chromatographic Determination of Triazine Herbicides

Abstract

A method for sample work-up and enrichment using Supported Liquid Membrane (SLM) and liquid chromatographic determination of triazine herbicides in natural waters was investigated. A porous PTFE membrane was impregnated with a water immiscible organic solvent, forming a barrier between two aqueous phases. With a flowing donor and a stagnant acceptor solution, an enrichment of the triazines was obtained. The various factors that influence the extraction efficiency and selectivity of the extraction procedure were experimentally studied. The obtained results were in good agreement with the developed theoretical model. The pH of the acceptor solution was found to be the critical limiting factor in obtaining higher extraction efficiencies and led to an extraction efficiency decrease with an increase in enrichment time. By increasing both the trapping capacity of the acceptor solution and the donor flow rate, the method detection limit of the triazines ranged from 0.03 to 0.16 μgL^?1 in natural waters with 20 minutes extraction time.     

Kinetic Study of Mercury(II) Transport through a Bulk Liquid Membrane Using Cyanex 301 as Carrier

A kinetic study of Hg(II) ions transport through a bulk liquid membrane (BLM) was investigated. The commercially available liquid bis(2,4,4‐trimethyl(pentyl) dithiophosphinic acid) (Cyanex 301) was employed as mobile carrier. The influences of the carrier concentration in the liquid membrane, HNO₃ concentration in the feed phase, type of organic solvent, composition of the receiving phase, and stirring speed on mass transfer were studied. Various solvents including CH₂Cl₂, CHCl₃, C₂H₄Cl₂ and CCl₄ were used as organic membrane. Among the solvents, CHCl₃ provided the superior results. The kinetic parameters (k₁, k₂, R_m^max, t^max, J_d^max, and J_a^max) were calculated for the interface reaction assuming two consecutive, irreversible first‐order reactions. The analysis of Hg(II) accumulation in liquid membrane and the rate‐controlling step under different experimental conditions were elucidated. The experiments demonstrated that Cyanex 301 is an appropriate carrier for Hg(II) transport through liquid membrane.     

Synthesis and Crystal Structure of A New Armed-tetraazacrown Ether and Its Liquid Membrane Transport of Alkali Metal Cations

Introduction　　Transportofcationsacrossanorganicliquidmem branewhichseparatestwowaterphaseshasbeenexten sivelyinvestigated .1Thesyntheticmacrocyclicligands ,suchascrownethers ,areusuallyusedasmodelcarrierstomimicthenaturallyoccurringantibioticmacrocycleswhichhavebeenshowntoalterthepermeabilityofbiologicalmembranestocertaincations .2 ,3 Thus ,theyhaveimpor tantapplicationsinbothchemistryandbiologytoselectivecomplexationofvariousmetalcations .4 ,5Itwasreportedthatthedivalenttransition metalcomp…     

用甲基丙烯酸十二酯/丙烯酸共聚物作乳状液膜稳定剂迁移锌(Ⅱ)

用甲基丙烯酸十二酯/丙烯酸共聚物作乳状液膜稳定剂迁移锌(Ⅱ);两亲高分子;乳状液膜;迁移;锌离子     

A Study on Complexation and Transport of Cr(III) Through a Chromogenic Aza Crown Liquid Membrane

A new chromogenic aza-crown-ether N-(8-hydroxyquinoline-7-methylene)-4-azadibenzo-18-crown-6-ether (HQMADCE) was synthesized through the condensation reaction of 4-azadibenzo-18-crown-6-ether, 8-hydroxy quinoline and formaldehyde. The synthesized chromogenic crown was characterized by various spectroscopic techniques and its complexation with Cr(III) was studied. The parameters like extraction constant (K_ex), stability constant (β), free energy change (ΔG), enthalpy change (ΔH) and change in entropy (ΔS) were calculated. Subsequently transport of Cr(III) through a bulk liquid membrane containing HQMADCE as carrier was studied. The permeation of metal was investigated as a function of various experimental variables viz. pH, carrier concentration, metal concentration and time. Furthermore, interference by other ions was also studied.     

Transport of Ca^2＋ Ion through a Bubbling Pseudo—emulsion Liquid Membrane with Calixarenes and Calixcrowns as Carriers

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Synthesis of New Aza-crown Ethers Containing Pyridine Ring and their Liquid Membrane Transport of Alkali Cations

IntroductionOxygen donor macrocycles such as crown ethers are well known to have strong complexation for alkali and alkaline earth ions1. On the other hand, polyazamacrocycles show a high affinity for transition metal ions. Nitrogen-oxygen mixed donor macrocycles can form stable complexes with both alkali and transition metal ions2~5. Most of the macrocycles with mixed donor sites bearing oxygen and sp3 nitrogen atoms, oxygen and sp2 nitrogen atoms, or oxygen and sp3 and sp2 nitrogen atoms hav…     

离子液体内耦合液膜迁移苯酚的研究

本文以N-甲基咪唑为原料,采用微波合成法,制备了疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),并将其作为液膜,对苯酚的内耦合液膜迁移进行了研究,考察了温度、搅拌速度、料液相酸度、初始浓度及解析相NaOH浓度等因素对苯酚迁移的影响,得出了最佳迁移条件:温度300 K,搅拌速度350 r/min,料液相pH为3.65,解析相NaOH浓度为0.8 mol/L.在最佳液膜条件下,对于10 mg/L苯酚溶液,迁移110 min,迁移率可以达到97.3%,膜相中有少量苯酚滞留.离子液体可循环使用.     

Stripping Analysis of Trace Metals at a Flow-Through Reticulated Vitreous Carbon Electrode after the Preconcentration by Supported Liquid Membrane Technique

Abstract

The performance of a flow-through mercury coated reticulated vitreous carbon (RVC) electrode in the potentiometric stripping analysis (PSA) of trace metals has been examined. A wall-jet glassy carbon cell was used for the comparative experiments. Experimental parameters influencing the stripping signals have been optimised in order to use the stripping analysis after the preconcentration and matrix isolation by supported liquid membrane (SLM) technique. The SLM with di-2-ethylhexyl-phosphoric acid (DEHPA) as the extractant in the membrane liquid for proton driven transport of trace metals across the membrane has been chosen. Results presented for lead determination in river water demonstrate the analytical advantages of coupled technique SLM-PSA.     

Transport of Tb3+in Dispersion Supported Liquid Membrane System with Carrier P507

The Tb³⁺ transport in dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride membrane (PVDF) as the liquid membrane support and dispersion solution including HCl solution as the stripping solution and 2‐ethyl hexyl phosphonic acid‐mono‐2‐ethyl hexyl ester (P507) dissolved in kerosene as the membrane solution, has been studied. The effects of pH value, initial concentration of Tb³⁺ and different ionic strength in the feed phase, volume ratio of membrane solution and stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on transport of Tb³⁺ has also been investigated, respectively. As a result, the optimum transport conditon of Tb³⁺ was that concentration of HCl solution was 4.0 mol/L, concentration of P507 was 0.10 mol/L, and volume ratio of membrane solution and stripping solution was 1.0 in the dispersion phase, and pH value was 5.2 in the feed phase. Ionic strength had no obvious effect on transport of Tb³⁺. Under the optimum condition studied, when initial concentration of Tb³⁺ was 1.0×10^?4 mol/L, the transport rate of Tb³⁺ was up to 95.2% during the transport time of 95 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The results were in good agreement with the literature data.