离子交换法提取D-对羟基苯甘氨酸

研究了离子交换树脂提取 D-对羟基苯甘氨酸的方法 ,包括树脂的筛选 ,吸附条件和洗脱条件的确定。     

Amidoximation of Cyano Group for Chelating Ion Exchange of Some Heavy Metal Ions from Wastewater

Ion exchange behavior of some heavy metal ions, Pb²⁺, Ni²⁺, and Cd²⁺, onto amidoximated polyacrylonitrile based Ce(IV) phosphate was investigated. Polyacrylonitrile based Ce(IV) phosphate was prepared and followed by functionalization of the cyano group to amidoxime group with hydroxylamine. The amidoximated resin was characterized using FT-IR and SEM. Removal of Pb²⁺, Ni²⁺, and Cd²⁺ ions from aqueous solution was examined by studying some factors using the batch technique such as effect of pH, contact time, initial metal ion concentration, and temperature. Some kinetic and isotherm models had been applied. The calculated amount of the sorbed values in case of the pseudo-second-order model are closer to the experimental data than that of the pseudo-first-order model, and with a correlation coefficients R² > 0.99. Therefore, the sorption of the three metal ions can be approximated more favorably by the pseudo-second-order model. The sorption process obeys the Freundlich isotherm model. The sorption has an endothermic nature which is indicated by the positive value of the enthalpy change, ΔH, the high positive values of the entropy change, and ΔS show the increased randomness at the solid/solution interface. The obtained negative values of free energy change, ΔG, indicate the feasibility and the spontaneous nature of the sorption process.     

Thermal,catalytic, antimicrobial,and chelating aspects of phenolic resin and its polychelates with f‐block elements

The polymeric ligand (resin) was synthesized by condensation of 2‐hydroxy‐4‐ethoxybenzophenone with ethane diol in the presence of polyphosphoric acid as a catalyst at 145°C for 10 h. The synthesized resin was used to study its ion exchange efficiency and to synthesize its polychelates with 4f‐block elements. The resin and its polychelates were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, IR, NMR, and thermogravimetric analyses. The molecular weight was determined using number–average molecular weight (M_n ) by a vapor pressure osmometry (VPO) method. Ion‐exchange studies at various concentrations of different electrolytes, pH, and rate have been carried out for f‐block elements. Antimicrobial activity of all polychelates and catalytic activity of selected polychelates in organic synthesis have been studied. It is observed that resin can be used as an ion‐exchanger and polychelates are found to be an efficient catalysts and antimicrobial agents. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Treatment of wastewater containing Pb and Fe using ion‐exchange techniques

Treatment of wastewater containing lead and iron was examined using two different ion‐exchange resins namely Duolite ES 467 (containing amino‐phosphonic functional groups) and a chelating ion‐exchange resin (containing hydroxamic acid functional groups). Initially different sorption parameters such as contact time, pH, concentrations of sorbent, sorbate and chloride ion were studied. The sorption kinetics was observed to be fast and equilibrium could be reached within 30 min. Lead sorption efficiency increased with increase in pH whereas the opposite trend was observed with iron. The presence of chloride ions greatly reduced the Pb sorption efficiency in the case of Duolite ES 467. Column studies were carried out to recover Pb and Fe individually using Duolite ES 467 resin. The maximum uptake of Pb at pH 2 and 3 was observed to be 11.63 and 33.96 g dm^?3 of resin respectively. Similarly, for Fe at pH 2 and 3 the uptake was observed to be 10.07 and 6.96 g dm^?3 of resin respectively. In the presence of chloride ions, column studies were carried out using Duolite ES 467 for iron and chelating ion‐exchange resin containing hydroxamic acid functional groups for lead sorption. Hydroxamic acid resin's loading capacity remains constant for at least up to 20 cycles. Copyright © 2005 Society of Chemical Industry     

Cesium Removal Demonstration Using Selected Actual Waste Samples from the Hanford Reservation Tank Farm

Abstract

Approximately 40 million curies of Cs‐137 are currently contained in High Level Waste stored in 177 underground storage tanks at the Hanford Nuclear Reservation near Richland, Washington. A series of actual waste, small‐scale column tests were performed to evaluate the performance of a selected ion exchange resin for cesium removal from a range of planned feed streams. These tests demonstrated that the selected cationic resin–SuperLig 644^®‐has more than adequate resin capacity to treat each of three potential feed streams. Furthermore, tests indicate an acceptable mass transfer zone for each of the three types of feed material, and that the elution of the resin can be accommodated within the design criteria for the proposed Waste Treatment Plant.     

Preparation and characterization of silanized silica gel‐supported poly(acrylic acid) network polymer and study of its analytical application as selective extractor for lead ion

A novel silanized silica gel (SSG)‐supported poly(acrylic acid) network polymer (ion exchanger) has been synthesized and characterized for the study of its analytical applications. The chemical nature of the ion exchanger has been elucidated with the help of FTIR, NMR, TGA, DSC, and SEM. The immobilization of the polymer network on SSG has been studied. The optimum pH range for quantitative extraction of lead was found to be 4.5–6.0. The effects of pH and stripping agent on extraction and elution of Pb(II), respectively, have been investigated. Ion exchange and break through capacity of the exchanger have been determined at room temperature. Pb(II) has been extracted quantitatively from various environmental samples. A plausible mechanism for lead ion exchange has been suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Comparative Study of Sc(III) Sorption onto Carbon-based Materials

The sorption behavior of Sc(III) on different materials including activated carbon (AC), carbon nanotubes (CNTs), graphene oxide (GO), and the chelating resin Chelex 100 was investigated. In general, the sorption of scandium increases with increasing pH. For pH in the range from 2.5 to 5.5, the sorption of Sc(III) onto CNTs, GO, and Chelex 100 is quantitative, whereas a significantly lower amount of scandium ions was retained on AC. The specific amount of Sc(III) adsorbed at pH 2 attained 2.1, 2.9, 36.5, and 37.9 mg g^?1 for AC-COOH, Chelex 100, GO, and CNTs-COOH, respectively. At pH 4, a similar value was obtained for oxidized AC (2.2 mg g^?1), whereas the specific amount adsorbed significantly increased for Chelex (23.4 mg g^?1). The highest values were obtained for GO (39.7 mg g^?1) and oxidized CNTs (42.5 mg g^?1). Better kinetic retention was observed at pH 2 for CNTs and GO, whereas at pH 4 the kinetic behavior of Chelex 100, GO, and CNTs toward Sc(III) was comparable.     

Lead removal from aqueous solutions by 732 cation‐exchange resin

Kinetics and thermodynamics of the removal of Pb²⁺ from an aqueous solution by 732 cation‐exchange resin in hydrogen type (732‐CR) were studied in the temperature range of 298–328 K and Pb²⁺ concentration range of 5–50 mol/m³. The effects of ion exchange temperature and initial lead ion concentration on the time evolution of the experimental concentration for the metal ion were investigated. Ion exchange kinetics of Pb²⁺ onto 732‐CR follow the Nernst‐Planck equation and unreacted‐core model (UCM). The diffusion coefficients of counter ions and the efficient diffusion coefficient of lead ions within the resin were calculated. The results show that the ion exchange process is favoured under the particle diffusion control mechanism. The ion exchange isotherm data agreed closely with the Langmuir isotherm. The maximum monolayer exchange capacity for Pb²⁺ was found to be 484.0 mg/g at 308 K. Thermodynamic studies show that Pb²⁺ onto 732‐CR is spontaneous and exothermic in nature. The ion exchange processes were verified by Energy Disperse Spectroscopy (EDS).     

SWELLING OF A CHELATING MACROPOROUS RESIN DURING METAL ION EXCHANGE

ABSTRACT

The kinetics of heavy metal ion exchange onto a commercial chelating resin was investigated from the standpoint of the swelling-shrinking experienced by the resin bead during the overall ion exchange process. Temporal measurements of the volume variations were carried out for every step of an operational cycle, metal load, elution and regeneration of the ion exchanger, using a microreactor mainly composed by a reaction cell, an optical microscope and an image treatment system. Experimental results were properly fitted to an empirical equation, whose parameters were used to characterize and compare different systems. A pseudosteady state kinetic model, which takes into account the volume variations of the resin bead during the ion exchange reaction, fits fairly well to experimental results, and was used to obtain the effective diffusion coefficients of the metals through the macroporous matrix. Finally, the study of the batch ion exchange kinetics of transition metal cations was completed with a potentiometric titration and other equilibrium determinations. These results were compared with those derived from swelling measurements.     

钼污染水体处理技术研究进展

钼是一种重要的稀有金属,但近年来钼污染频发,对生态环境安全和人体健康造成了严重的影响。本文综述了目前国内外对环境中钼污染的处理技术(包括人工湿地法、化学沉淀法、离子交换法及吸附法),详细介绍了各种技术的处理效果、影响因素及相关模型。人工湿地虽能将钼分离出水体,但含有钼的基质和功能植物存在污染转移等不可控风险;化学沉淀法对中低浓度污水的去除效果较好,但剩余污泥较难处理,不能被循环利用;离子交换法能有效将污钼分离出水体,并通过解吸实现树脂多次利用,但树脂适应性较差,对pH值等反应控制条件要求较高;传统材料为主的吸附法使用廉价材料富集污染物质,但存在二次污染的问题。最后指出钼污染处理的新型功能材料将向低成本和资源化的方向发展,铁基材料具有较好的前景。     

Shale Oil Denitrogenation with Ion Exchange

Abstract

The nitrogen-containing aromatics normally found in crude retorted shale oils have been shown to be involved in reactions leading to the deposition of insoluble gums and sediments. These nitrogen-containing compounds must be removed in order to permit the effective utilization of the shale oil product.

A process is proposed in which the nitrogen-containing compounds found in raw shale oil are removed by mild hydrodenitrogenation followed by resin ion exchange. Ion exchange data from experimentation involving six jet fuel (15M-271°C) and diesel fuel (271–343°C) boiling point cuts are presented. Amberlyst A-15, a macroreticular, strongly acidic, cation exchange resin is used in this study. Three types of experiments were performed: batch sorption equilibrium experiments, batch sorption kinetics experiments, and dynamic ion-exchange column performance tests. The Langmuir isotherm was found to describe the equilibrium sorption behavior of the shale oil/ion-exchange resin system fairly Well. The sorption kinetics are described using a quadratic-driving force model.     

Hydraulic Testing of Ion Exchange Resins for Cesium Removal from Hanford Tank Waste

Abstract

The granular ion exchange resin SuperLig^® 644 is the ion exchange resin of choice for ¹³⁷Cs separation from Hanford tank wastes. Current testing activities are evaluating both ground gel and spherical resorcinol‐formaldehyde (RF) resins as alternatives to the sole‐source supplied SL‐644 while achieving comparable loading and elution performance. The purpose of this testing was then to compare the bed forces, resin particle breakage, and differential pressure across the resin bed during multiple load‐elute cycles. These tests were conducted in a small‐scale column with high flow rates to simulate the hydraulic conditions that would be experienced in a full‐scale column.     

Kinetics and Equilibrium Studies for the Removal of Cobalt,Manganese, and Silver in Ethanol using Dowex 50W-x8 Cation Exchange Resin

Organic solvents such as ethanol, find a wide range of applications in fuel, pharmaceutical industries, food industries, and paint formulations, among others. The removal of Ag(I), Co(II), and Mn(II) ions in ethanol by cation exchange resin, Dowex 50W-x8, was investigated. The adsorption characteristics of metal ions onto Dowex 50W-x8 resin were described by Langmuir isotherms. The maximum sorption exchange capacities at 298 K were obtained as 47.4 mg g^?1, 52.6 mg g^?1, and 58.5 mg g^?1 for Ag(I), Co(II), and Mn(II), respectively. The data was also fitted to Temkin and Dubinin-Radushkevich adsorption isotherm models to evaluate other adsorption properties. The ion exchange of silver, cobalt, and manganese on cation exchange resin followed pseudo-second-order kinetics, and the intraparticle diffusion was rate-determining step. The thermodynamic parameters indicated that the sorption of metal ions onto Dowex 50W-x8 resin was spontaneous (negative ΔG°) and endothermic in nature (positive ΔH°) implying that the adsorption capacity increased with increasing temperature. The resin can be regenerated by eluting metal ions with 3.0 mol L^?1 HNO₃ followed by washing it with 10 mL of Millipore water and 10 mL of 2.0 M NaOH, respectively. The proposed method was applied for metal ion removal in real ethanol samples.     

Preparation and characterization of UV‐grafted ion‐exchange textiles in continuous electrodeionization

Ion‐exchange textiles (IETs) suitable for use in continuous electrodeionization (CEDI) stacks were prepared using the ultraviolet (UV)‐induced grafting of acrylic acid and sodium styrene sulfonate for cation‐exchange textiles, or 2‐hydroxyethyl methacrylate and vinylbenzyl trimethyl ammonium chloride for anion‐exchange textiles, onto nonwoven polypropylene fabric using benzophenone as photoinitiator. Although the ion‐exchange capacity (2.2 meq g^?1) of the prepared strong acid cation‐exchange textile was lower than that of IRN77 strong acid cation‐exchange resin (4.2 meq g^?1), the overall rate constant of IET was very high due to its low crosslinking and high specific surface area. There was no significant difference between the two different media in terms of the Co(II) removal rate. Furthermore, the current efficiency for IETs was higher than that of IRN77 cation‐exchange resin during a CEDI operation, with efficiencies of 60% and 20%, respectively. The IET also showed the faster exchange kinetics. Therefore, IETs prepared in this study proved to have desirable ion‐conducting characteristics within the CEDI systems. Also this study revealed that the primary removal mechanism in CEDI is the transport of ions through a medium and not the ionic capacity of a medium. Copyright © 2004 Society of Chemical Industry     

Equilibrium data of the exchange of Cu2+, Cd2+ and Zn2+ ions for H+ on the cationic exchanger Lewatit TP‐207

Equilibrium ion exchange isotherms in aqueous medium of H⁺/Cu²⁺, H⁺/Zn²⁺ and H⁺/Cd²⁺ on a weak acid resin Lewatit TP‐207, at different pH values and at 298 K have been determined in order to assess the possibility of using ion exchange to eliminate heavy metal ions from industrial aqueous liquid streams. The experimental equilibrium data have been satisfactorily correlated using a Langmuir‐type empirical equation. It was found that the operating resin capacity with respect to each metal ion increased with increase in solution pH, in accordance with a second‐degree polynomial equation. Taking into account the variation of operating capacity with pH, each system exhibited a unique separation factor, namely all the experimental points can be described by a unique isotherm in a dimensionless form. Resin Lewatit TP‐207 exhibited the following selectivity order: Cu²⁺ > Zn²⁺ > Cd²⁺ at 298 K. Copyright © 2004 Society of Chemical Industry     

离子交换色谱法分离硼同位素的研究进展

综述了离子交换色谱法分离硼同位素的进展。在目前的研究方法中,主要采用强碱性阴离子交换树脂、弱碱性阴离子交换树脂和硼特效树脂作为柱填充材料,本文对于这3种树脂的优缺点进行了比较,最后对影响单级分离因子的因素进行了讨论。表明离子交换色谱法是一种极具潜力的硼同位素分离方法,具有高效节能的特点。     

Application of a carbon sorbent for the removal of cadmium and other heavy metal ions from aqueous solution

Treatment of flax shive with sulfuric acid produces a carbonaceous material that has been used to remove metal ions from aqueous solution. Metal ions including Cd(II), Cu(II), Cr(III), Co(II), Ni(II), Zn(II) and Pb(II) have been investigated for kinetic behaviour and sorption capacities. These metal ions show fast sorption kinetics following a first order rate equation. Cadmium was chosen as representative of these metal ions and a detailed study was carried out. The effect of pH on sorption was studied and it was found that maximum uptake occurred above pH 3–7, sorption was accompanied by release of protons into the solution and a ratio of [H⁺] released to [Cd²⁺] sorbed of approximately 2 was found. The sorption capacity showed no significant increase with increase of temperature. The presence of other metal ions such as K⁺, Na⁺, Mg²⁺ and Ca²⁺ decreases the Cd(II) capacity, indicating competition for the ion exchange sites. Successive sorption of Cd(II) shows that the capacity exceeds the monolayer capacity calculated from the Langmuir equation. Column studies showed good performance over a total of seven cycles of loading/stripping. These studies indicate that the sorption mechanism for these metal ions is related to a reversible ion exchange process on the carbon surface. © 2002 Society of Chemical Industry     

Introduction of bifunctionality into the phosphinic acid ion-exchange resin for enhancing metal ion complexation

In nuclear industry the role of conventional strong cation exchange resins is limited as they function less in high acid media. The phosphorous group that has got more affinity towards actinide elements is chosen as a chelating group and the phosphinic acid ion exchange resin was synthesized. The extraction ability of the phosphinic acid resin for plutonium (Pu) from HNO₃ medium as well as from H₂SO₄ medium was studied. Though the resin shows better extraction for Pu than the strong cation exchanger resins at higher acidities, its kinetics is slow. In order to enhance the kinetics as well as to improve upon selectivity, a sulphonic group is introduced into the phosphinic acid resin. To verify the effect of bifunctionality extraction studies have been carried out with Pu from different acid media of varying concentrations. Sulphonated phosphinic acid resin shows a 2-fold increase in distribution coefficient (k_d) as well as it reached equilibrium very fast compared to the phosphinic acid resin. It is postulated that the sulphonic acid ligand provides an access mechanism for the metal ions into the polymer matrix while it is the phosphinic acid group that is responsible for selective coordination of metal ions. Thus bifunctionality is coupling of an access mechanism to a recognition mechanism. The experiments carried out demonstrated the applicability of sulphonated phosphinic acid resin in the nuclear industry.     

Molecularly Imprinted Ion-Exchange Resin for Fe3+

Abstract

Ion exchange resins selective for the sequestration of Fe³⁺ from aqueous solutions containing citrate were prepared by the molecular imprinting technique. Sorption characteristics of imprinted resins prepared with high (85 mole%) and low (3 mole%) amounts of covalent cross‐linking were examined. Experiments to determine loading capacity and selectivity, relative to several metal ions of physiological significance, were performed. The Fe³⁺ capacity of the highly cross‐linked resin was larger but the selectivity was lower.