二（2-乙基已基）磷酸萃取氨基苯甲酸的平衡特性

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.     

二(2-乙基己基)磷酸萃取氨基苯甲酸的相平衡分配系数

络合萃取法分离极性有机物稀溶液具有高效性和高选择性,本文以二（２－乙基已基）磷酸（Ｄ２ＥＨＰＡ）为络合剂;正辛烷或正辛醇为稀释剂,在不同的ＰＨ值条件下实验测定了氨基苯甲酸稀溶液的萃取相分配系数,讨论了影响因素,分析了萃合物的组成。提出了平衡分配系数的关系式。     

Competitive Adsorption of Ag+, Pb2+, Ni2+, and Cd2+ Ions on Vermiculite

Competitive adsorption of Ag⁺, Pb²⁺, Ni²⁺, and Cd² ions on vermiuculite in a binary, ternary, and quaternary mixture was investigated in batch experiments. The effects of the presence of Ag⁺, Ni²⁺, and Cd²⁺ ions on the adsorption of Pb²⁺ ions were investigated in terms of the equilibrium isotherm. Experimental results indicated that Pb²⁺ ions always favorably adsorbed on vermiculite over Ag⁺, Ni²⁺, and Cd²⁺ ions. The adsorption equilibrium data of Pb²⁺ ions better fitted the Langmuir model than the Freundlich model. The results showed that the pseudo-second-order kinetics model was in good agreement with the experimental results for all metal ions, and the adsorption rate among the metal ions followed Ag⁺ > Pb²⁺ > Ni²⁺ > Cd²⁺. The desorption and regenration study indicated that vermiculite can be used repeatedly and be suitable for the design of a continuous process.     

Extraction Equilibria of 4-Hydroxypyridine using Di (2-ethylhexyl) Phosphoric Acid

Extractions of 4-Hydroxpyridine (4HP) from aqueous solutions using Di(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant in 1-octanol and kerosene were studied. The factors that affected the distribution coefficient (D), such as equilibrium pH, the concentration of D2EHPA, and the type of diluents were discussed. The interaction mechanism between 4HP and D2EHPA was validated by infrared spectroscopic analysis. D increased with the increase of the concentration of D2EHPA and peak values appeared at equilibrium pH = 3.6–5.0. D in the polar diluent (1-octanol) was much higher than those in the non-polar diluent (kerosene). The extraction reaction was found to be a proton-transfer process and D2EHPA mainly reacted through its –OH with –N– of 4HP. The apparent reactive extraction equilibrium constants K ₁₁ and K ₁₂ were obtained by fitting the experimental data of extraction equilibrium. By comparing calculated D values from the proposed model with the experimental ones, the accuracy of the proposed model was examined.     

Distribution Behavior of Amino Acid by Extraction with Di(2-ethylhexyl) Phosphoric Acid

Abstract

The distribution equilibrium of l-tryptophan (l-Trp) by extraction with di(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in n-hexane was studied. The effects of L-Trp and D2EHPA concentrations, pH, and ionic strength, particularly of L-Trp loading in the organic phase, on extraction equilibrium were examined in detail. When the amino acid loading ratio (the molar concentration ratio of the equilibrium amino acid in the organic phase to the initial dimeric D2EHPA) was less than 3 × 10^?3, one L-Trp molecule was extracted by forming a complex with four monomeric D2EHPA molecules, and the extraction equilibrium constant (K _e) was determined to be 0.045 dm³/mol. Above this loading ratio the equilibrium formula did not hold, and the apparent equilibrium constant (K _a) increased significantly with increasing loading ratio. The phenomenon was explained by taking into account two parallel reactions in which fewer D2EHPA molecules, two and one respectively, were needed to extract one l-Trp molecule.     

Synergic Extraction of Folic Acid with Di(2-ethylhexyl) Phosphoric Acid and Amberlite LA-2

The influences of extractants concentrations and solvent polarity on the efficiency of folic acid separation by synergic extraction with Amberlite LA-2 and di(2-ethylhexyl) phosphoric acid (D2EHPA) mixture have been analyzed. The results indicated the formation of an interfacial compound which includes one molecule of folic acid and one of D2EHPA, the hydrophobicity of this compound being increased by solvation with Amberlite LA-2 molecules. The number of aminic molecules participating in the interfacial complex formation is controlled by solvent polarity and D2EHPA concentration, decreasing from 3 to 1 with the increase of these two parameters. The results indicated that the most important synergic effect corresponds to the extractants mixture dissolved n-heptane, at low D2EHPA concentration in the organic phase (5 g/l).     

Modeling of Facilitated Transport of Phenylalanine by Emulsion Liquid Membranes with Di(2-ethylhexyl)phosphoric Acid as a Carrier

ABSTRACT

A mathematical model is developed in this paper to simulate the facilitated transport of phenylalanine (Phe) in emulsion liquid membrane (ELM) systems with di(2-ethylhexyl)phosphoric acid as a carrier. The model takes into account the mass transfer in both the external aqueous phase and the organic membrane phase interfacial reaction as well as membrane breakage during agitation. The model is tested by comparing theoretical predications with experimental results using Phe extraction by ELM processes. It is found that the model is valid for simulating the facilitated transport of Phe with ELM under various experimental conditions.     

Evaluation of Mononuclear Ni(II) Complex of a Tetra-cryptanded Vic-dioxime and its Model Compound 14-Membered N2O2S2-Macrobicyclic Ligand as Pb2+, Cd2+, and Hg2+ Extractants

Abstract

A macrobicyclic ligand and its mononuclear Ni(II) complex were studied as extractants for Pb²⁺, Cd²⁺, and Hg²⁺. The metal picrates were used for extraction experiments. The solutions of the ligands in chloroform and dichloromethane were used as organic phases. The most effective transport was observed for Cd²⁺ picrate among the tested metal picrates with dichloromethane. The effect of pH on the extraction efficiency was evaluated for both organic solvents. The cations were stripped from the organic phase with 0.75 M nitric acid and the ligands were determined spectrophotometrically in the proper wavelength. The recovery% values of the ligands were calculated at pH 3.5.     

二乙基二硫代氨基甲酸钠与Cu2+、Pb2+、Cd2+、Ni2+的络合性研究

在0.01 mol/L硼砂缓冲溶液中,以二乙基二硫代氨基甲酸钠(DDTC)为配体,与Cu2 、Pb2 、Cd2 、Ni2 络合,用紫外可见分光光度法测定了金属络合物的吸收光谱,并计算出它们的稳定常数.实验结果表明,DDTC分别在257、282 nm处出现两个最大吸收峰,而Cu2 、Pb2 、Cd2 、Ni2 配合物分别在紫外区的304、305、303、321 nm处有最大吸收峰;DDTC与Cu2 、Pb2 、Cd2 、Ni2 形成的配合物的稳定常数分别为4.05×1011,2.67×1011,2.14×1011,4.01×1010,其稳定性顺序为:Cu(DDTC)2＞Pb(DDTC)2＞Cd(DDTC)2＞Ni(DDTC)2.     

Effect of Macrocycle Type on Pb2+ Transport through an Emulsion Liquid Membrane

Abstract

The relative effectiveness of 14 different macro-cycles in transporting Pb(NO₃)₂ has been determined at 25 °C using a water-toluene-water emulsion membrane system. The largest amount of Pb²⁺ transport was found with dideeyl-1,1O-diaza-18-crown-6 (91%), followed by dicyclohexano-18-crown-6 (81%), di-tert-butyl-dicyclohexano-l8-crown-6 (77%), 1,10-diaza-18-crown-6 (27%), and cryptand 2.2.1 (4,7,13,16,21,24-pentoxa-1,10-diazabicyclo(8, 8, 5)-tricosane) (16%). The use of the other macrocycles produced little Pb²⁺ transport. Analysis of the transport results shows that, for most effective transport, the macrocycle should distribute preferentially to the organic phase and the log K value for the binding of the macrocycle with Pb²⁺ must be large enough for quantitative extraction of the Pb2 + into the membrane. However, this log K value must be sufficiently smaller than that for interaction of Pb²⁺ with P₂O₇ ^4?, the receiving phase complexing agent, to allow a large Pb²⁺ concentration gradient to be established. These features provide information which should be useful in designing systems for cation separations using emulsion membranes.     

新型杯[4]芳烃衍生物对Pb2+,Cd2+的萃取性质

研究了新型杯[4]芳烃D对Pb2+,Cd2+离子的液-液萃取性质,并将其与自制的杯[4]芳烃A及其衍生物B、C对Pb2+,Cd2+离子的液-液萃取性质进行了比较.结果表明,与化合物A～C相比,D对Pb2+萃取率最高,在本实验条件下,可达到42.8%;测试的四种化合物对Cd2+离子的萃取效率均不佳,未经任何修饰的杯[4]芳烃A的萃取效率最高,仅8.5%.推测对Cd2+的萃取为阳离子交换机理.     

新型杯[4]芳烃衍生物对Pb~(2+),Cd~(2+)的萃取性质

研究了新型杯[4]芳烃D对Pb2+,Cd2+离子的液-液萃取性质,并将其与自制的杯[4]芳烃A及其衍生物B、C对Pb2+,Cd2+离子的液-液萃取性质进行了比较。结果表明,与化合物A~C相比,D对Pb2+萃取率最高,在实验条件下,可达到42.8%;测试的四种化合物对Cd2+离子的萃取效率均不佳,未经任何修饰的杯[4]芳烃A的萃取效率最高,仅8.5%。推测对Cd2+的萃取为阳离子交换机理。     

Poly (methacrylic acid) modified biomass for enhancement adsorption of Pb2+, Cd2+ and Cu2+

In this study, the graft copolymerization of methacrylic acid onto the biomass of baker's yeast was carried out in aqueous medium using potassium persulfate (PPS) as initiator. The poly (methacrylic acid) modified biomass obtained was characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS) and microscopic analyses. The number of functional groups was determined by potentiometric titration. The adsorption capacity of the modified biomass for Pb²⁺, Cd²⁺ and Cu²⁺ showed a significant increase compared with the pristine biomass, due to the presence of a large number of functional groups. According to the Langmuir equation, the maximum uptake capacities (q_m) for Pb²⁺, Cd²⁺ and Cu²⁺ were 243.9, 108.7 and 73.5 mg g^?1, respectively. Adsorption kinetics study showed that completion of the adsorption process needed only 30 min. The loaded biosorbent was regenerated using EDTA solution and used repeatedly three times with little loss of uptake capacity. Good results were obtained when the modified biomass was used to treat simulated wastewater containing Pb²⁺, Cd²⁺ and Cu²⁺. Copyright © 2007 Society of Chemical Industry     

二-(2-乙基己基)磷酸合成工艺研究

研究了合成二－（2－乙基己基）磷酸的工艺优化条件，通过加入无水AlCl3，严格控制反应温度，控制三氯氧磷加入量过量3％等措施，合成的二－（2－乙基己基）磷酸萃取稀土元素性能优于标准萃取剂。     

Removal of Cd2+, Cu2+, Ni2+, and Pb2+ ions from aqueous solutions using tururi fibers as an adsorbent

This work investigates the removal of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ ions from aqueous solutions using tururi fibers as an adsorbent under both batchwise and fixed‐bed conditions. It was found that modification of the tururi fibers with sodium hydroxide increased the adsorption efficiencies of all metal ions studied. The fractional factorial design showed that pH, adsorbent mass, agitation rate, and initial metal concentration influenced each metal adsorption differently. The kinetics showed that multi‐element adsorption equilibria were reached after 15 min following pseudo‐second‐order kinetics. The Langmuir, Freundlich, and Redlich–Peterson models were used to evaluate the adsorption capacities by tururi fibers. The Langmuir model was found to be suitable for all metal ions. Breakthrough curves revealed that saturation of the bed was reached in 160.0 mL with Cd²⁺ and Cu²⁺, and 52.0 mL with Ni²⁺ and Pb²⁺. The Thomas model was applied to the experimental data of breakthrough curves and represented the data well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40883.     

Membrane Extraction of Ag(I), Co(II), Cu(II), Pb(II), and Zn(II) Ions with Di(2-Ethylhexyl)phosphoric Acid under Conditions of Electrodialysis with Metal Electrodeposition

Theoretical Foundations of Chemical Engineering - New methods for extracting cobalt and zinc ions from sulfuric acid solutions, of silver and lead ions from nitric acid solutions, and of copper...     

Gels, emulsions, and liquid crystals in extraction systems with Di(2-ethylhexyl)phosphoric acid

Di(2-ethylhexyl)phosphoric acid (D2EHPA, a well-known extractant) and various metals are used to exemplify the variety of dispersion structures that appear in extraction systems in bulk phases and in the interfacial region. The formation of basic terbium di(2-ethylhexyl)phosphate organogels, sodium di(2-ethylhexyl)phosphate microemulsions, and nickel di (2-ethylhexyl)phosphate liquid crystals is demonstrated.     

Kinetics of Acidic Oxidative Dissolution of Vitreous (Oxy)chalcogenide Materials Sensitive to Ag+ (Cu2+, Pb2+, Tl+)

The dissolution kinetics of ion-conducting and semiconducting (oxy)chalcogenide glasses that are used or hold promise as membranes of ion-selective electrodes has been considered. The experimental data on the influence of the structural–chemical features of glasses and the temperature, the acidity, and the oxidation potential of etchants on the rate of steady dissolution are analyzed and generalized.     

Effect of Bis-(2-ethylhexyl)Phosphoric Acid on Sodium Bis-(2-ethylhexyl)Phosphate Microemulsion for Selective Extraction of Non-Ferrous Metals

The effect of bis-(2-ethylhexyl)phosphoric acid (DEHPA) on the region of existence, conductivity and structure of sodium bis-(2-ethylhexyl)phosphate (NaDEHP) microemulsion has a dual nature and depends on DEHPA concentration. In the system NaDEHP–DEHPA–kerosene–water, the narrowing of the microemulsion region is observed with DEHPA concentration in the organic phase growth from 0.1 to 0.5 mol/L. The increase of DEHPA concentration in the organic phase from 0.1 to 0.4 mol/L leads to the reduction of electrical conductivity of the microemulsions. Based on the conductivity and viscosity measurements, we suppose the transition from reverse microemulsion with isolated droplets to percolate microemulsion at volume fraction of water 0.18 ( \(W = C_{{H_{2} O}} /C_{\text{NaDEHP}}\)  = 8). Droplet size of the microemulsions increases linearly with W growth. The rise of DEHPA concentration in the organic phase from 0.1 to 0.3 mol/L causes the growth of the coefficient at W in the equation d = kW + b from 0.038 to 0.249, i.e., it increases the slope of the lines. In contrast, DEHPA introduction at the concentration 0.1 mol/L (in the organic phase) leads to the expansion of the microemulsion region, does not affect the conductivity and decreases the coefficient at W. The rate of copper recovery into the microemulsion increases considerably with the rise of DEHPA concentration from 0.0 to 0.3 mol/L; no dual effect is observed. The following composition of the microemulsion for non-ferrous metals leaching is recommended: C _NaDEHP = 1.6 mol/L, C _DEHPA = 0.3 mol/L (in the organic phase); W = 8–32.     

Extraction of L-synephrine by Bis(2-ethylhexyl)phosphoric acid/n-octanol Reversed Micelles

In this study, reversed micelles of Bis(2-ethylhexyl)phosphoric acid/n-octanol was prepared to investigate the purification of L-synephrine in Citrus aurantium fruit crude extract. The reverse micellar system formed was confirmed with atomic force microscopy and the effect of important factors on extraction efficiency, such as the pH of the aqueous phase, molar ratio of water to surfactant, surfactant concentration, cationic ion concentration, and extraction time, was studied. Under the optimal operational conditions, the purity of L-synephrine was improved to be >85% and the total yield >98%. Mathematic analysis and experimental results exhibited that the extraction process in this system was effectuated mainly via electrostatic interactions between L-synephrine and the surfactant.