Liquid Membrane Transport of Hg(II) by an Azocalix[4]arene Derivative

Abstract

A kinetic study of Hg(II) transport from an aqueous donor solution into an aqueous acceptor solution through a liquid membrane containing 25,26,27–tribenzoyloxy‐28‐hydroxy‐5,11,17,23‐tetra‐(4‐n‐butylphenylazo)calix[4]arene 1 as a carrier was studied. The kinetic parameters (k ₁, k ₂, R _m ^max, t _max, J _d ^max, J _a ^max) for the transport were investigated in terms of the effect of temperature, the stirring rate, the carrier concentration, and the type of solvent. The kinetics of transport was analyzed in the formalism of two consecutive irreversible first‐order reactions. The membrane entrance rate, and exit rate constants were increased with increasing of temperature stirring rate, and carrier concentration. The membrane entrance rate and exit rate constants depended on the type of solvent and was found to be in order of CH₂Cl₂> CHCl₃> CCl₄. The activation energy values are calculated as 30.67±2.64 and 57.33±4.90 kj mol^?1 for extraction and reextraction, respectively. The values of calculated activation energy indicate that the process is diffusionally controlled by species.     

Highly Efficient and Selective Transport of Au(III) through a Bulk Liquid Membrane using Potassium-dicyclohexyl-18-crown-6 as Carrier

Abstract

The facilitated transport of Au(III) through a chloroform bulk liquid membrane containing potassium-dicyclohexyl-18-crown-6 as a selective ion carrier was designed. Au(III) as [AuBr₄]^?, quantitatively transported across the liquid membrane. In the receiving phase, L-cysteine acts as a specific stripping agent. The amount of Au(III) transported through the liquid membrane after 120 minutes was (96.2±1.3)%. The type of halide and its concentration, pH of source and receiving phase and also the type of stripping agents were optimized. The selectivity and efficiency of gold(III) transport from aqueous solutions containing various metal ions were investigated. The presence of EDTA in the source phase diminished drastically the competitive effect of interfering metals ion.     

Highly Efficient and Selective Transport of Cu(II) with a Cooperative Carrier Composed of Tetraaza-14-Crown-4 and Oleic Acid through a Bulk Liquid Membrane

Tetraaza-14-crown-4 and oleic acid was successfully applied for transport of Cu(II) in chloroform bulk liquid membrane. The uphill moving of Cu(II) during the liquid membrane transport process has occurred. The main effective variable such as the type of the metal ion acceptor in the receiving phase and its concentration, tetraaza-14-crown-4 and oleic acid concentration in the organic phase on the efficiency of the ion-transport system were examined. By using L-cysteine as a metal ion acceptor in the receiving phase, the maximum amount of copper (II) transported across the liquid membrane was achieved to 96 ± 1.5% after 140 minutes. The selectivity of copper ion transport from the aqueous solutions containing Pb²⁺, Tl⁺, Ag⁺, Co²⁺, Ni²⁺, Mg²⁺, Zn²⁺, Hg²⁺, Cd²⁺ and Ca²⁺ ions were investigated. In the presence of CH₃COONH₄ and Na₄P₂O₇ as suitable masking agents in the source phase, the interfering effects of Pb⁺² and Cd²⁺ were diminished drastically.     

Highly Efficient Liquid Membrane Transport of Dyes Using Calix[4]arene-Linked Triphenylene Dimers as Carriers

The extraction of dyes from aqueous phase to organic phase using calix[4]arene-linked triphenylene dimers (1a and 1b) with large π-cavity as extractants were examined. 1a and 1b showed outstanding extraction percentage for four common dyes [Orange G sodium salt (OG), Brilliant ponceau (BP), Methyl Green (MG), and Xylenol Orange disodium salt (XO)]. The highest extraction percentage of 1a was 95% for MG. Moreover, the abilities of liquid membrane transport of 1a and 1b for dyes were studied. The influences of pH value, concentration, solvent, stirring speed, and the temperature on liquid membrane transport was investigated to optimize the transport condition. The results of liquid membrane transport suggested 1a and 1b were excellent carriers for tested dyes with high fluxes. The high concentration in the source phase or membrane phase, CH₂Cl₂, high stirring speed, and low temperature were favorable for the efficiency of liquid membrane transport. The high extraction percentages and outstanding liquid membrane transport abilities indicated that 1a and 1b possessed excellent complexation for dyes based on the π-π stacking action between dyes and triphenylene units.     

Selective Facilitated Transport of Uranium(VI) Across a Bulk Liquid Membrane Containing Benzoyltrifluoroacetone as Extractant-Carrier

Abstract

A study has been made on carrier-mediated transport of uranium(VI) using a bulk liquid membrane prepared by dissolving benzoyltrifluoroacetone (HBTA) in carbon tetrachloride. The source phase comprised of a solution of UO₂ ²⁺ or its binary mixture with other cations such as Th⁴⁺, Hf⁴⁺, Zr⁴⁺, Fe³⁺, La³⁺, Cu²⁺, Co²⁺, Mn²⁺, Ni²⁺, and Zn²⁺ in aqueous solutions of pH 6.0, while 0.1 M hydrochloric acid was serving as a stripping agent in the receiving compartment. The interference from Th⁴⁺ and a few other cations could be eliminated by using trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (DCTA) as a proper masking agent in the feed solution. Various factors influencing the transport process have been studied and an uphill transport (>99%) of uranium(VI) from the source phase could be accomplished under optimum conditions.     

Facilitated Transport of Cd(II) Through a Supported Liquid Membrane with Aliquat 336 as a Carrier

Selective removal of cadmium from wastewaters is very important, because cadmium is toxic for the environment and for human health. This work is a comprehensive study on the selective removal of Cd(II) from aqueous solutions by using a co-current flow flat sheet supported liquid membrane system. 4.4 × 10^?4 M Cd(II) concentration was used as a feed solution in the experiments. Toluene containing Aliquat 336 was used as the membrane liquid in the membrane system. Parameters such as the properties of feed and stripping solutions, carrier concentration, and flow rate, which have roles in transport of Cd(II) ions, were optimized. The efficiency of the system is expressed in terms of permeability and flux values, and transport efficiency. The optimum process conditions for the Cd(II) transport are experimentally found as follows: The feed solution as 2 M HCl, the carrier concentration as 0.1 M Aliquat 336, the stripping solution as 0.06 M EDTA, and the flow rates for the feed and stripping solutions as 50 mL/min and 80 mL/min, respectively. Under these conditions, the Cd(II) transport efficiency is found to be 82%.     

PC-88A为载体的大块液膜体系Cu(II)传输动力学

采用以2-乙基己基膦酸-2-乙基己基单酯(PC-88A)为载体、CHCl3为膜溶剂的大块液膜分离体系,研究了搅拌速度、载体浓度、体系温度对铜离子迁移的影响. 获得了不同反应温度下的表观反应速率常数,萃取与反萃取表观反应活化能分别为41.97和8.59 kJ/mol. 铜离子的迁移过程可用2个串联的准一级不可逆过程描述,萃取过程化学反应为控速步骤,反萃取过程扩散为控速步骤.     

应用厚体液膜法处理含镍废水

采用内耦合大块液膜分离技术,考察料液相浓度、料液相pH值、载体浓度、反萃取剂浓度、料液相中柠檬酸钠与镍(Ⅱ)的摩尔比对镍(Ⅱ)迁移率的影响,研究了以三辛基甲基氯化铵(TOMAC)为载体的液膜中镍(Ⅱ)的迁移规律。结果表明,在其它条件一定时,当料液相浓度为0.03M,料液相pH值控制在10左右,载体浓度为6%,反萃取浓度为0.05￣0.07M,料液相中柠檬酸钠与镍离子的摩尔比值为11∶,迁移时间为180min时,镍(Ⅱ)的提取率达到50%以上。     

Transport of Hg2+ Ions across a Supported Liquid Membrane Containing Calix[4]arene Nitrile Derivatives as a Specific Ion Carrrier

Abstract

The transport behavior of Hg²⁺ from aqueous solution through a flat‐sheet‐supported liquid membrane (SLM) has been investigated by using of calix[4]arene derivatives (1 and 2) as carriers and Celgrad 2400 and 2500 as the solid support. The effect of solvent type and anions such as chloride and nitrate ions on the transport of Hg²⁺ was examined. Danesi mass transfer model was used to calculate the permeability coefficients for each parameter studied. The highest values of permeability were obtained with 2‐nitrophenyl ethyl ether (NPOE) solvent and the influence was found to be in the order, NPOE>chloroform>xylene. The transport efficiency on the supported liquid membrane was dependent on the type of carrier, its characteristics, and the type of the solvent.     

The Transport of Copper(II) through Hollow Fiber Renewal Liquid Membrane and Hollow Fiber Supported Liquid Membrane

Abstract

In this paper, hollow fiber renewal liquid membrane (HFRLM) and hollow fiber supported liquid membrane (HFSLM) were used to simultaneously remove and recover copper(II) from aqueous solutions, and the transport performance of these two techniques were compared under the similar conditions for the system of CuSO₄ +D2EHPA in kerosene +HCl. The results showed that the HFRLM process was more stable than the HFSLM process. The HFRLM process had a higher overall mass transfer coefficient than that of HFSLM process in single-pass experiments. These were because the renewal effect of the liquid membrane layer could reduce the mass transfer resistance of the lumen side and replenish the loss of the membrane liquid in the HFRLM process. The transport results were better in the HFRLM process than that in the HFSLM process with recycling experiments. Therefore, HFRLM technique is a promising method for simultaneous removal and recovery of heavy metal from aqueous solutions.     

Zinc and Copper Separation through an Emulsion Liquid Membrane Containing Di‐(2‐Ethylhexyl) Phosphoric Acid as a Carrier

The separation of zinc and copper ions from sulfuric acid solutions by an emulsion liquid membrane (ELM), using di‐(2‐ethylhexyl) phosphoric acid (D2EHPA) as a carrier, has been investigated. The batch extraction of zinc and copper was carried out while varying a selection of experimental conditions, i.e., stirring speed, treatment ratio, concentrations of metal ions in the feed phase, carrier and Span 80 concentration in the membrane, and internal phase concentration. The results obtained demonstrate the effectiveness of D2EHPA as a carrier for the separation of zinc and copper from sulfuric acid media using an ELM. An increase of the D2EHPA concentration beyond 2 vol.‐% does not result in the improved extraction of zinc because the viscosities of the membrane and emulsion have a trend to increase for higher carrier concentrations. It was found that the extraction rate of copper was affected by the carrier concentration in the liquid membrane and by the pH and metal content in the external phase. A 3 vol.‐% concentration of surfactant in the organic phase was required to stabilize the emulsion. The number of stages required for the extraction of zinc and copper by an ELM was determined from McCabe‐Thiele plots.     

Selective Transport of Alkali and Alkaline Earth Metallic Ions through a Supported Liquid Membrane Containing Tripentyl Phosphate as a Carrier

Abstract

A selective transport system for alkali and alkaline earth metallic ions with a perchlorate ion as a pairing ion species through a supported liquid membrane (SLM) containing tripentyl phosphate (TPP) as a carrier is described. The SLM used is a porous polypropylene membrane impregnated with TPP solution in o-nitrophenyloctylether. The effects of the pairing ion species, the initial perchlorate concentration, and the TPP concentration on metallic ion transportability are examined under various experimental conditions. The permeation velocities of the metallic ions in the transport system followed the sequence Li⁺?Na⁺>K⁺>Mg²⁺; that is, a highly selective transport for Li⁺ ion was observed. Compared with the transport rates of alkali metallic ions, those of transition metallic ions such as Cu²⁺ and Fe³⁺ ions are very low. The permeation velocities of alkali and alkaline earth metallic ions through an SLM are dependent on the concentrations of perchlorate and TPP. Equations for the permeation velocities of Li⁺, Na⁺, K⁺, and Mg²⁺ ions through an SLM, based on two concentrations of perchlorate and TPP, are proposed.     

Separation of Ni(II) and Cd(II) Ions with Supported Liquid Membranes (SLM) using D2EHPA as a Carrier

Separation of nickel(II) and cadmium(II) ions from sulphate solution with use of supported liquid membranes (SLM) has been studied. Di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in kerosene was used as the ion carrier. Obtained data were compared with data from polymer inclusion membranes (PIM) experiments. It was shown that use of SLM membranes enables separation of Ni(II) and Cd(II) ions. Experimental results data show that faster transport and higher recovery factor values were obtained for supported liquid membranes.     

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     

Kinetic and Equilibrium Modeling of Pb(II) and Co(II) Sorption onto Rose Waste Biomass

Abstract

An attempt was made to assess the biosorption potential of rose waste biomass for the removal of Pb(II) and Co(II) ions from synthetic effluents. Biosorption of heavy metal ions (>90%) reached equilibrium in 30 min. Maximum removal of Pb(II) and Co(II) occurred at pH 5 and 6 respectively. The biosorbent dose for efficient uptake of Pb(II) and Co(II) was 0.5 g/L for both metals. The biosorbent size affected the Pb(II) and Co(II) biosorption rate and capacity. Rose waste biomass was found effective for Pb(II) and Co(II) removal from synthetic effluents in the concentration range 10–640 mg/L. Equilibrium sorption studies showed that the extent of Pb(II) and Co(II) uptake by the rose waste biomass was better described by the Langmuir isotherm in comparison to the Freundlich model. The uptake capacities of the two metal ions were 156 and 27.15 mg/g for Pb(II) and Co(II) respectively.     

Kinetic and equilibrium studies of Pb(II) and Cd(II) removal from aqueous solution onto colemanite ore waste

The adsorption characteristics of Pb(II) and Cd(II) onto colemanite ore waste (CW) from aqueous solution were investigated as a function of pH, adsorbent dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the adsorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The adsorption capacity of CW was found to be 33.6 mg/g and 29.7 mg/g for Pb(II) and Cd(II) ions, respectively. Analyte ions were desorbed from CW using both 1 M HCl and 1 M HNO₃. The recovery for both metal ions was found to be higher than 95%. The mean adsorption energies evaluated using the D-R model indicated that the adsorption of Pb(II) and Cd(II) onto CW were taken place by chemisorption. The thermodynamic parameters (ΔG^o, ΔH^o and ΔS^o) showed that the adsorption of both metal ions was feasible, spontaneous and exothermic at 20-50 °C. Adsorption mechanisms were also investigated using the pseudo-first-order and pseudo-second-order kinetic models. The kinetic results showed that the adsorption of Pb(II) and Cd(II) onto CW followed well pseudo-second order kinetics.     

Selective Transport of Cu(II) across a Polymer Inclusion Membrane with 1-Alkylimidazole from Nitrate Solutions

The selective transport of copper(II), zinc(II), cobalt(II), and nickel(II) ions from nitrate solutions across polymer inclusion membranes (PIMs), which consist of cellulose triacetate as polymeric support, o-nitrophenyl pentyl ether as plasticizer, and 1-alkylimidazole (alkyl from hexyl- to decyl) as ion carrier was reported. PIM was characterized by using atomic force microscopy (AFM) technique. The results show that Cu(II) can be separated very effectively from other transition metal cations as Zn(II), Co(II), and Ni(II) (at a concentration of 10^?3 mol/dm³ each). Alkyl substituents at position 1 of the imidazole ring have been found to affect the hydrophobic properties and initial flux of the transported metal ions. The efficiency of separation of metal ions by 1-alkylimidazole followed the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II). The highest selectivity coefficient for Cu(II) was found with 1-hexylimidazole and its 1 mol/dm³ solution in PIM. Separation of the ions was more effective for the nitrates(V) than for chlorides.