弱碱阴离子交换树脂对酸性氨基酸分离性能的研究

本文采用几种不同类型的弱碱阴离子交换树脂对谷氨酸、天门冬氨酸和苏氨酸的分离性能进行了研究,考察了树脂结构、淋洗剂和树脂交换基团的型式对分离性能的影响。结果发现以pH～4缓冲溶液处理树脂,以醋酸,盐酸溶液分部淋洗两种酸性氨基酸得到完全分离。     

吸水树脂吸附分离研究进展

吸水树脂,也称高弹性凝胶,是一种新型功能高分子材料,具有优良的吸水和保水性能,已广泛用作生理卫生用品等,而很少用作吸附分离材料.本文在对吸水树脂的基本类型与主要特点、影响吸液性能的因素进行简要介绍的基础上,对吸水树脂的结构及其吸液机理、配位原子和配位基及其作用、重金属离子吸附行为、吸附过程影响因素进行了评述,并对吸水树脂应用于吸附研究进行了展望.     

用低交换容量聚苯乙烯型强酸性阳离子交换树脂柱色谱分离中性氨基酸

通过磺化苯乙烯 -二乙烯苯共聚物或商品化的聚苯乙烯型强酸性阳离子交换树脂 ( 0 0 1× 7)的逆磺化反应 ,得到一系列不同交换容量的聚苯乙烯型强酸性阳离子交换树脂 .研究了丙氨酸和缬氨酸及缬氨酸和亮氨酸在这些树脂柱上的色谱分离 .结果表明 ,用两种方法得到的树脂对丙氨酸和缬氨酸的色谱分离性能基本相同 ;同时中性氨基酸与聚苯乙烯型强酸性阳离子交换树脂之间的作用包括离子作用和疏水作用 ,且二者之间存在协同作用 .树脂的交换容量较低时对中性氨基酸有更好的分离性能     

聚丙烯酰胺型配体交换色谱载体的合成及分离氨基酸

合成了以亲水性聚丙烯酰胺为骨架的含有可与铜离子形成五元环螯合物配位基团的螯合树脂,这些树脂的Cu~(2+)络合物作为配体交换色谱载体对中性氨基酸进行了分离,并与2种已知螯合树脂的Cu~(2+)络合物作为载体的色谱行为作了比较。本文合成的树脂具有最好的分高性能,研究了色谱条件对分离的影响,讨论了色谱分离机制。     

Zn2＋型磺酸树脂对维生素B12的配位吸附及洗脱性能

原位吸附;分离;Zn2＋型磺酸树脂对维生素B12的配位吸附及洗脱性能     

高效离子色谱分离柱填料的研究Ⅰ.阴离子交换树脂附聚微球

用粒径约0.5微米季胺化单分散交联聚苯乙烯胶乳与粒径为5～30微米磺化交联聚苯乙烯共聚物微球藉库伦力附聚得到了阴离子交换树脂微球,并对磺化深度,基球和胶乳的粒径比以及交联度等对阴离子交换树脂附聚微球色谱性能的影响进行了分析。用这种阴离子交换树脂附聚微球作为HPIC分离柱的填料;用自制的全多孔强阳离子交换树脂YSG-SO_3H为抑制柱填料,仅用10厘米长的分离柱在约27分钟内即可使F~-、Cl~-、No_2~-、HPO_4~-、Br~-、No_3~-、及SO_4~-等阴离子混合样按顺序全分离。     

不同类型阴离子交换树脂对Cr(Ⅵ)的吸附性能研究

通过静态吸附实验、动力学实验,从3种吸附去除Cr(Ⅵ)的离子交换树脂中优选出DEX-Cr树脂,研究了pH、温度对其交换性能的影响,进一步对树脂的动态吸附-再生性能和重复使用稳定性进行了考察。结果表明DEX-Cr树脂对Cr(Ⅵ)的吸附去除效果好,且重复使用稳定性高,可以作为分离去除Cr(Ⅵ)的高效吸附剂。     

离子交换法分离乳酸的研究

本文对离子交换法分离乳酸的离子交换树脂、交换相平衡和交换动力学进行了研究,并在离子交换柱上测定了南开大学化工厂生产的201×4树脂的交换曲线。实验结果说明,用离子交换法分离发酵液中乳酸是可行的。     

络合物离子色谱在微量金属分析中的新发展

评述了络合物ＩＣ（包括阳离子交换ＩＣ、配位ＩＣ、阴离子交换ＩＣ和离子对色谱）在微量金属分析中的新发展，以配位化学基本理论对金属络合物ＩＣ的保留行为和分离机理进行讨论，并对各种金属络合物ＩＣ技术和应用进行比较和对照。     

离子交换法分离乳酸

本文在对多种吸附剂和离子交换树脂进行筛选的基础上，获得了一种对乳酸具有优良吸附性能的弱碱型离子交换树脂，测定了乳酸在该树脂上的离子交换平衡数据，建立了数学模型，研究了其它无机盐的存在对离子交换平衡的影响，同时测量了乳酸在该树脂上的交换速率和穿透曲线．上述研究对于乳酸分离，特别是从稀溶液中分离乳酸提供了一种新的方法，对其它有机酸的分离也具有参考意义．     

Separation of Neutral Amino Acids with Ligand Exchange Resins

Four neutral amino acids (Gly, Ala,.Val and Leu) were separated with ligand exchange resins. The separation capacity of the ligand exchange resins is compared with that of common ion exchange resins. The effects of eluent, column temperature, and central metal ions of the support on the separation are studied. The relationship between matrix structure of resins and their separation capacity is analysed.     

Effects of ligand density and pore size on the adsorption of bovine IgG with DEAE ion-exchange resins

Immunoglobulin G is an important plasma protein with many applications in therapeutics and diagnostics, which can be purified effectively by ion exchange chromatography. The ligand densities and pore properties of ion-exchange resins have significant effects on the separation behaviors of protein, however, the understandings are quite limited. In this work, with bovine immunoglobulin as the model IgG, the adsorption isotherms and adsorption kinetics were investigated systematically with series of diethylaminoethyl ion-exchange resins with different ligand densities and pore sizes. The Langmuir equation and pore diffusion model were used to fit the experimental data. The influences of ligand density and pore size on the saturated adsorption capacity, the dissociation constant and the effective diffusivity were discussed. The adsorption capacities increased with the increase of ligand density and the decrease of pore size, and an integrative parameter was proposed to describe the combined effects of ligand density and pore size. It was also found that the effective pore diffusion coefficient of the adsorption kinetics was influenced by pore sizes of resins, but was relatively independent on the ligand densities of resins. For a given protein, the ligand density and pore size should be optimized for improving the protein adsorption.     

Separation of amines by ligand exchange: Part IV ligand exchange with chelating resins and cellulosic exchangers

Chelating, sulfonic and cellulosic exchangers were compared in ligand exchange chromatography. Chelating resins retain metal ions the best, but have a low ligand binding capacity. Cellulosic exchangers show excessive metal leakage. Sulfonated polystyrene resins loaded with nickel ions give best results in most cases. Data are presented on ligand exchange chromatography of simple aliphatic amines, hydrazine and substituted hydrazines, purine and pyrimidine bases.     

Ion Exchange Separation of Platinum and Palladium by Nucleophilic Displacement With Thiocyanate or Thiourea1,2

The separation of platinum and palladium, by adsorption onto weak base anion exchange resins, Amberlite XE 299, or ionex (derived from Amberlite XE-305) from 1M hydrochloric acid, followed by ligand substitution with sulfur nucleophiles is described.

In the thiourea system, cationic thiourea complexes are produced, which cannot be readsorbed into the resin. In the thiocyanate system the formation of Pd(SCN)₄ ^2- is favored in both solution and polymer phases. The Pd(SCN)₄ ^2-. readsorption into the anion exchange resin is the basis for the separation of platinum from palladium.     

Effect of resin cross-linking and temperature on anion exchange separation of gallium and indium

Anion exchange separation of Ga-In on Dowex 1 resins of 2, 4, 8, and 10 nominal cross-linkings, respectively, was investigated at tracer loadings. The influence of temperature on the exchange reaction was also studied on the different resins. Separation factors, plate heights, and resolutions for the two peaks were calculated from the elution curves. Best separations were achieved with Dowex 1X4 due to the most promising values for both plate height and resolution. It was also found that the separation factors as well as the plate heights decreased with growing temperature.     

The role of temperature in ion exchange processes of separation and purification

The evolution of ion exchange processes for separation and purification of substances by use of the influence of temperature both on the equilibrium and the dynamic properties of some ion exchange resins is discussed. Significant improvement of some ion exchange separations, diminishing of reagents consumption and waste quantities is achieved. In the same way, environmentally non-hazardous reagentless ion exchange methods of divalent and monovalent ionic mixtures separation are developed. This report is based on experimental studies of the equilibrium, dynamic and some other properties of ion exchange resins.     

Ion exchange chromatography of monoclonal antibodies: Effect of resin ligand density on dynamic binding capacity

Dynamic binding capacity (DBC) of a monoclonal antibody on agarose based strong cation exchange resins is determined as a function of resin ligand density, apparent pore size of the base matrix, and protein charge. The maximum DBC is found to be unaffected by resin ligand density, apparent pore size, or protein charge within the tested range. The critical conductivity (conductivity at maximum DBC) is seen to vary with ligand density. It is hypothesized that the maximum DBC is determined by the effective size of the proteins and the proximity to which they can approach one another. Once a certain minimum resin ligand density is supplied, additional ligand is not beneficial in terms of resin capacity. Additional ligand can provide flexibility in designing ion exchange resins for a particular application as the critical conductivity could be matched to the feedstock conductivity and it may also affect the selectivity.     

Evaluation of anion exchange resins for plutonium-uranium separations in nitric acid

Pellicular, macroreticular and microreticular (gel-type) anion exchange resins were compared for the separation of plutonium from nitric acid solutions of mixed plutonium-uranium. AS Pellionex SAX (pellicular resin) and Amberlite IRA-93 (weak base macroreticular anion exchange resin) were found to have better uranium washing and plutonium eluting characteristics than any of the resins tested. However, the capacity of the pellicular resin was much lower than the other resins.     

Selective Recovery of Ammonia Nitrogen from Wastewaters with Transition Metal-Loaded Polymeric Cation Exchange Adsorbents

Extracting valuable products from wastewaters with nitrogen-selective adsorbents can offset energy-intensive ammonia production, rebalance the nitrogen cycle, and incentivize environmental remediation. Separating nitrogen (N) as ammonium from other wastewater cations (e.g., K⁺, Ca²⁺) presents a major challenge to N removal from wastewater and N recovery as high-purity products. High selectivity and capacity were achieved through ligand exchange of ammonia with ammine-complexing transition metals loaded onto polymeric cation exchange resins. Compared to commercial resins, metal–ligand exchange adsorbents exhibited higher ammonia removal capacity (8 mequiv g⁻¹) and selectivity (N/K⁺ equilibrium selectivity of 10.1) in binary equimolar solutions. Considering optimal ammonia concentrations (200–300 mequiv L⁻¹) and pH (9–10) for metal–ligand exchange, hydrolyzed urine was identified as a promising candidate for selective TAN recovery. However, divalent cation exchange increased transition metal elution and reduced ammonia adsorption. Ultimately, metal–ligand exchange adsorbents can advance nitrogen-selective separations from wastewaters.