Recovery and Concentration of Metal Ions. III. Concentration and Temperature Effects in Multi membrane Hybrid System

Abstract

The performance of the multi membrane hybrid system (MHS) made up of ion-exchange membranes and a bulk liquid membrane (D2EHPA in kerosene) has been examined. Fluxes and the separation between Zn(II), Mn(II), Cu(II), Co(II), and Ni(II) sulfates have been studied as dependent on the concentration of aqueous phases and temperature. The results show a saturation of fluxes at increased concentrations of aqueous feed or strip solutions. The total limiting fluxes are ～1 × 10^?9 mol/cm^2.s whereas the limiting fluxes for specific metal ions vary in the range from 6 × 10^?12 to 5 × 10^?10 mol/cm²-s. The effect of temperature on MHS transport results in an activation energy of 16 to 30 kJ/mol depending on the metal species. The optimum conditions for separating metals are determined by the concentration of a feed solution in the range from 0.001 to 0.01 M and the concentration of sulfuric acid in a stripping solution in the range from 0.01 to 0.5 M. Selectivity coefficients β^Zn+Mn+Cu _Co+Ni calculated as the ratio of stationary fluxes amount to 30–40, and are practically constant in the 298 to 328 K temperature interval.     

Biosorptive Flotation in Metal Ions Recovery

Abstract

Heavy metals can be removed from dilute aqueous solutions in many ways. Among the innovative ones may be classified a process consisting of biosorption followed by flotation. A metal cation, cadmium, was examined; the metal was abstracted by microorganisms belonging to the Actinomycetes, i.e., Streptomyces clavuligerus and Streptomyces griseus, which have a filamentous morphology, and hence present a flocculent character. Dissolved-air flotation was the technique applied on a laboratory scale without the addition of any flotation surfactant. The parameters investigated in the batch mode were contact time, recycle ratio, solution pH, Cd concentration, biomass addition, and use of a frother (ethanol). Promising results were obtained; in certain cases an almost quantitative cadmium abstraction, followed by higher than 90% biomass recovery, was found.     

Studies on Stannic Selenoarsenate. II. Separation of Uranium from Numerous Metal Ions

Abstract

Stannic Selenoarsenate has been synthesized by adding 0.05 M sodium selenite and 0.05 M sodium arsenate to a 0.05 M solution of stannic chloride in a volume ratio of 1:1:1 at pH 1. A tentative structure has been proposed on the basis of chemical composition, pH titrations, and infrared and thermogravimetric analyses. Distribution coefficients of several metal ions have been studied in hydrochloric acid, citric acid, ammonium citrate-citric acid, and water-dioxane systems. The unusual adsorption behavior of uranium has been utilized for its quantitative separation from several metal ions.     

Development of Spiral-Type Supported Liquid Membrane Module for Separation and Concentration of Metal Ions

Abstract

Experiments on the single permeation of cobalt, nickel, and zinc, and the simultaneous permeation of cobalt and nickel were performed using newly developed spiral-type supported liquid membrane modules. These metal ions were successfully separated and concentrated. EHPNA (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) was used as the carrier of cobalt and nickel, and D2EHPA (di-(2-ethylhexyl)phosphoric acid) for the recovery of zinc. In these modules the flow pattern of both feed and stripping solutions is plug flow, which led to very high recovery of metal ions. For example, 99.97% of cobalt in the feed was recovered in a once-through operation, and cobalt could be pumped against its concentration gradient even if the ratio of the metal concentration in the strip phase to that in the feed phase was as high as 70,000. It was confirmed by a life test of the module that the membrane was stable for more than one month without appreciable decrease in metal flux, and that the degraded membrane could be easily and rapidly regenerated without interrupting the permeation of metal ions by re-impregnating the module with the organic membrane solution. The degree of removal for both single and simultaneous permeation of cobalt and nickel was satisfactorily simulated by design equations of the module and the flux equations in which the formation of aggregates of metal-carrier complexes was taken into account.     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Thiourea- or Urea-Formaldehyde Chelating Resin

Abstract

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) chelating resins have been synthesized and they have been used in the adsorptions of Ag(I), Cu(II), and Zn(II) metal ions by batch and column methods. The effect of initial acidity of Ag(I) solution and the adsorption capacities of TF and UF resins by batch method and the separation of Ag(I) ions from Cu(II) and Zn(II) base metal ions by the column method were examined experimentally. The adsorption capacities of TF and UF resins were found as 58.14 and 47.39 mg Ag(I)/g by batch method and 30.7 and 4.66 mg Ag(I)/g, 0.80 and 0.121 mg Cu(II)/g, and under 0.002 mg Zn(II)/g by the column method, respectively. It was found that Ag(I) ions showed higher affinity towards TF resin than UF resin, compared with Cu(II) or Zn(II) ions, and Ag(I) could be separated more effectively by TF resin from Cu(II)and Zn(II) ions.     

Synthetic Inorganic Ion-Exchangers. XVI. Thin-Layer Chromatography of Metal Ions on Zirconium Tungstate: Quantitative Separation of Hg(II) from Several Other Metal Ions and from Mixtures

Abstract

Thin-layer chromatography of 23 metal ions in 10 aqueous and mixed solvent systems has been performed on zirconium tungstate ion-exchange material. Several important binary and ternary separations have been achieved. Quantitative separation of Hg(II) from Pb²⁺, Zn²⁺, Cd²⁺, Bi³⁺, Co²⁺, and mixtures has been achieved using 1,4–dioxane as solvent.     

Recovery and Separation of Metal Ions from Aqueous Solutions by Solvent‐Impregnated Resins

The recovery and separation of metals from aqueous solutions is one of the research hotspots in hydrometallurgy, environment protection, analytical chemistry, etc. Much attention has been paid to solvent‐impregnated resins (SIRs) since these were firstly proposed for the extraction of metals. SIRs are characterized by high efficiency and selectivity, convenient preparation, and easy operation because they combine the unique advantages of solvent extraction and ion exchange. The preparation and features of SIRs are summarized and their applications in the extraction of various metals from solutions are reviewed. In addition, the equilibrium, thermodynamics, and sorption kinetics of the metals onto SIRs are elucidated in detail.     

杯芳烃衍生物与碱金属离子、碱土金属离子配合的研究进展

杯芳烃衍生物作为"第三代超分子",对金属离子有着优异的结合力和选择性,已广泛用于金属离子的萃取、离子色谱、催化、跨膜运输、离子通道以及自组装分子层等领域。综述了近年来杯芳烃及其衍生物与金属离子,主要是碱金属、碱土金属阳离子配合的最新进展。     

Dissolved-Air Flotation of Metal Ions

Abstract

Metal ions (copper, nickel, zinc, and ferric ions) were separated from dilute aqueous solutions by dissolved-air flotation. The ions were either precipitated as sulfides or floated (as ions) by xanthates. Copper and nickel were selectively separated; promising results were obtained with single, binary, and ternary mixtures. The effect of several parameters (solution pH, addition of chemical reagents at varying concentrations, and the presence of other ions) on the removal of ions was studied. The collectorless flotation of copper ions was also investigated.     

Equilibrium Extraction and Concentration of Multivalent Metal Ion Solutions by Using Winsor II Microemulsions

Abstract

Experimental results on the selective extraction and concentration of bivalent copper into the aqueous core of a water-in-oil microemulsion in equilibrium with an aqueous phase are presented. We have developed an electrostatic model which describes this phenomenosn as a preferential substitutin of the conthe counterions of the surfactant by the introduced bivalent cations. We have assumed that the adsorption of counterions onto the charged surface of the reverse micelle can be modeled by the Stern double layer model. Comparisons of the theoretical predictions against the experimental results are encouraging. The positive features of the model and its limitations are discussed.     

ICP-MS测定液晶中金属离子及溴离子和碘离子含量

建立了用电感耦合等离子体质谱法(ICP-MS)测定液晶中14种金属离子及溴离子和碘离子含量的方法.采用NMP作为溶剂,直接进样法建立校准曲线进行测定,结果表明:回收率为87％～117％,RSD在1.2％～3.7％,检测限为0.00049～0.02907 ng·mL-1.     

金属烧结过滤器在PTA母固回收系统的应用

针对目前PTA（精对苯二甲酸）装置中精制段和氧化段母固回收存在的问题,提出母固回收单元工艺改进：采用金属粉末烧结滤芯回收母液中的TA（对苯二甲酸）和其它有机物,不但可以降低系统中PX（对二甲苯）单耗,同时也可以减少废水中的COD含量。此改进工艺能使企业节能减排,增强企业竞争力,提高企业经济效益。     

磷化液中金属离子的分析

0 引言 磷化作为金属涂装前处理工艺,已经得到广泛的应用.磷化工艺以前主要以锌系、钙系、锰系或锌-钙、锌-锰系二元磷化体系为主.随着涂装对表面处理质量要求的提高,三元磷化开始在阴极电泳中广泛应用.它能显著提高涂层的附着力,改善磷化膜质量,增强涂层的耐蚀性能.     

Biosorption of Metal Ions from Aqueous Solutions

Abstract

Copper biosorption from aqueous solutions by calcium alginate is reported in this paper. The experimental section includes potentiometric titrations of biosorbents, batch equilibrium and kinetic studies of copper biosorption, as well as fixed-bed biosorption experiments. The potentiometric titration results show that the surface charge increases with decreasing pH. The biosorption of copper strongly depends on solution pH; the metal ion binding increases from 0 to 90 percent in pH ranging from 1.5 to 5.0. In addition, a decrease in ionic strength results in an increase of copper ion removal. Kinetic studies indicate that mass transfer plays an important role in the biosorption rate. Furthermore, a fixed-bed biosorption experiment shows that calcium alginate has a significant capacity for copper ion removal. The two-pK Basic Stern model successfully represents the surface charge and equilibrium biosorption experimental data. The calculation results demonstrate that the copper removal may result from the binding of free copper and its hydroxide with surface functional groups of the biosorbents.     

Single and Multi-Component Adsorption of Metal Ions by Acinetobacter sp. FM4

This paper reports biosorption of Cr(VI), Cu(II), and Ni(II) onto Acinetobacter sp. FM4 biomass isolated from soil irrigated with tannery effluent from single, binary, and ternary metal solutions. Optimum pH for biosorption was found to be 2.0 for Cr(VI), 5.0 for Cu(II), and 6.0 for Ni(II) ions. Sorption capacities for Cr(VI), Cu(II), and Ni(II) ions were estimated as 90 mg g-1, 93.3 mg g-1, and 66.7 mg g-1, respectively. The combined effect of adsorbing one metal ion in the presence of another metal ion reduced the adsorption capacity of either metal ion. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion was confirmed by Fourier Transform Infrared (FTIR) spectroscopy.     

金属离子对厌氧消化的影响

金属离子对微生物的生长具有重要作用,是生物厌氧消化反应器稳定运行的重要影响因素。从轻金属离子和重金属离子两个方面对厌氧消化的影响进行了总结。     

Interactions of Metal Ions with DNA and Some Applications

Nucleic acids play a critical role in life as we know it. It contains the necessary information required for the structure and function of a living organisms. Metal ions play a critical role in stabilizing conformations. In the well-known double helix structure of DNA, metal ions stabilize a particular conformation that ensures storage and propagation of genetic information. Metal ions, however, can interact with various sites on nucleic acids. Moreover, metal coordination can have a tremendous impact on the structure, conformation, stability and the electronic properties of the nucleic acids. The interactions are controlled by the relative affinity of metal ion coordination to the negatively charged phosphodiester backbone versus binding to other donor sites located in the nucleobases. The canonical Watson–Crick base pairs (A-T and G-C) as well as non-canonical base pairs (Hoogsteen and wobble) and mismatched pairs are often sites for metal ion interactions. In this review, an overview will be provided of the structure of different forms of nucleic acids (DNA and RNA) and the impact of different metal ions on their stability and structure. In addition, the recent applications of metal-DNA interactions in nanotechnology, biosensor and bioelectronics will also be discussed along with some therapeutic applications of metal complexes.     

吡啶类受体的合成及其对金属离子的识别研究

设计合成了基于吡啶环的新型受体分子,利用质谱、核磁共振氢谱及熔点测定等对受体分子的结构进行了表征,并利用电导滴定、紫外光谱对受体分子与金属离子在水溶液中的识别进行了研究。研究结果表明,在水溶液中受体分子对多种过渡金属离子有着很好的选择性识别能力,吡啶环与过渡金属离子之间存在相互作用。     

Chelation and Foam Separation of Metal Ions from Solutions

Abstract

An experimental study was conducted on the chelation and foam separation of trace amounts of cadmium, zinc, and lead from their water solutions. The chelation agents ethylenediaminetetraacetate (sodium salt), sodium diethyl-dithiocarbamate, and citric acid were used with sodium dodecylsulfate (SDS) as a foam-producing agent. The chelation agents did not produce metal complexes that were very surface active. The foam-producing agent produced metal ion complexes that were surface active and resulted in appreciable separation of the metal ions. The use of 100 ppm SDS resulted in separation of 90% of the zinc ions from solution containing 2 to 20 ppm zinc. At concentrations below and above this, the removal efficiency dropped significantly