CL-7402萃淋树脂分离富集铅的研究及其应用

通过静态和动态实验,研究了CL-7402萃淋树脂吸附铅的性能和减压微色谱柱分离富集铅的最佳条件。实验表明,此萃淋树脂吸附快,吸附容量大。在减压条件下,以1mol/LHBr为上柱介质,2mol/LHNO3为洗脱液,可使铅与铜、铁等金属离子快速分离。采用三溴偶氮胂光度法测定样品中的铅。     

Kinetics of the surface tension of micellar solutions: Comparison of different experimental techniques

The kinetics of the surface tension of micellar solutions of nonionic surfactant Triton X-100 is measured experimentally by means of three different techniques: oscillating jet, maximum bubble pressure and inclined plate. They allow to study the micellization kinetics at various time scales (from a few milliseconds to a few seconds) in fairly large concentration region up to 50 times CMC. The experimental data are satisfactorily explained by a theoretical model accounting for the kinetics of micellization, diffusion of surfactant species and expansion of the bubble interface. By this model are computed the characteristic times of diffusion and micellization, which are of comparable magnitude (about 5 to 200 ms), and the Gibbs' elasticity. The micellization time constant corresponds to the slow relaxation process known to coincide with the disintegration of micelles. Comparing our data with other data from literature one can conclude that more realistic information for the micellization kinetics is obtained by the maximum bubble pressure and the oscillating jet method. The inclined plate seems too slow to measure the relaxation processes in micellar solutions of this surfactant.     

Liquid chromatography of polymer mixtures by a combination of exclusion and full adsorption mechanisms. Three- and four-component polymer blends

Summary Coupling of full adsorption-desorption and size-exclusion chromatography (FAD-SEC) has been applied to the separation and molecular characterization of three- and four-component polymer blends. The method is based on the full adsorption of alln orn−1 components of the polymer blend in a specially designed FAD minicolumn. By appropriate eluent switching the adsorbed polymers are desorbed stepwise from the FAD minicolumn into an on-line SEC column for molecular characterization. It is shown that the desorption isotherms of particular blend components give valuable information about the appropriate displacer composition. The exact position of the desorption isotherms depends, however, both on the amount of polymer adsorbed and in the presence of other, chemically different, polymers within FAD column. The nature and composition of the displacer must, therfore, be adjusted if the intervals between the desorption of particular blend components are to be large enough to prevent displacement overlap. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.     

New stationary phases of conjugated π-electron systems for HPLC—characterization of structure and dynamics by solid state NMR spectroscopy

Four new stationary phases for HPLC were prepared by modifying silica gel with a trifrnctional aminoalkyl silane. A conjugated π-electron system was linked to the amino group either directly or with a carboxylic anhydride as a spacer in between. Characterization and dynamic measurements of the new stationary phases were performed by solid state NMR spectroscopy. The results of the ²⁹si and ¹³C CP/MAS techniques were compared with the recently developed ¹H MAS-only technique. Despite strong homonuclear dipole-dipole interactions it was possible to obtain well resolved ¹H MAS spectra of those stationaru phases with a high degree of crosslinking. Limited mobility of the aromatic ligand fragments is common for all examined stationaryu phases. The chromatographic properties of the new phases were tested by their ability tio sepatate a mixture of eight PAHS. It could be shown that the π-π interaction mechanism is responsible for the separation of the eight PAHs, because the elution order of the PAHs did not changem despite the use of both a nonpolar mobile phase (n-heptane) and a polar mobile phase (methanol/ water mixture).     

Recent development in HPLC enantioseparation — a selected review

Summary Recent developments in the field of separating optical isomers by HPLC are discussed in this brief review. In particular it is focussed on various techniques for direct enantioseparation, the interpretation of possible enantioselective separation mechanisms, and the advantages and limitations of the diverse methods. This goal is supported by representative and selected examples of chiral separations.     

Study of the concentration and separation of cadmium with microcrystalline phenolphthalein modified by crystal violet

A new method for cadmium separation and concentration with microcrystalline phenolphthalein modified by crystal violet (CV) was developed in the paper. In the presence of potassium iodide (KI) and CV, cadmium are quantitatively absorbed on microcrystalline phenolphthalein in the pH range 1.0-6.0 as the forms of water-insoluble ion-associated complexes (CdI₃⁻)·(CV⁺) and (CdI₄²⁻)·(CV⁺)₂. Effect of different parameters such as phenolphthalein amount, stirring time, the concentration of CV and KI, various salts and metal ions was studied in detail. During the present study, a significant enhancement of the extraction of cadmium was observed. Cd(II) can be completely separated from Zn(II), Fe(II), Co(II), Ni(II), Mn(II), Cr(III) and Al(III) in this microcrystalline system and well concentrated without the interference of these metal ions at high level. The possible reactive mechanism of cadmium concentration has been discussed. Analytical results obtained by this new method were very gratifying.     

弱酸树脂D113对S-腺苷-L-蛋氨酸的交换行为及分离应用研究

考察了S-腺苷-L-蛋氨酸 (S-adenosyl-L-methionine, SAM) 在弱酸树脂争光D113上的静态吸附及分离行为,利用Langmuir等温式对平衡等温线进行了拟合,实验表明,随着pH的提高,平衡交换量增加,提高温度和SAM的初始浓度在一定程度上能促进内扩散过程,利用D113树脂在f 1.7×30.0cm小型柱上从酵母提取液中分离SAM的得率为90%以上,纯度达87%以上。     

等离子体聚合及其聚合物的应用

本文着重综述了烃,含氮、氧的有机化合物,碳氟化合物以及有机硅化合物的等离子体聚合。同时还系统地介绍了等离子体聚合物在制备反渗透膜、分离膜、材料表面的涂层等方面的国内外的最新研究成果。     

Retention, kinetics and thermodynamics profile of cadmium adsorption from iodide medium onto polyurethane foam and its separation from zinc bulk

The sorption behaviour of 2.5 × 10⁻⁵ M solution of Cd(II) on polyurethane foam (PUF) from iodide medium have been investigated. The conditions were optimized from aqueous solutions of different pH (1-10) and of acids of varied concentration (0.01-1.0 M). The maximum concentration of KI was found to be 0.24 M and equilibration time was established to be 20 min. The data successfully followed the Freundlich and Dubinin-Radushkevich (D-R) isotherms at low metal ion concentration while Langmuir isotherm followed at higher metal ion concentration. The Freundlich parameter 1/n = 0.66 ± 0.02 have been evaluated whereas D-R isotherm yields the sorption free energy E = 10.5 ± 0.1 kJ mol⁻¹ indicating ion exchange type chemisorption. The monolayer coverage (XL) constant of Langmuir isotherm was found to be 23.7 ± 0.4 mg g⁻¹. The numerical values of thermodynamics parameters enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) indicated the endothermic and spontaneous nature of sorption. The Scatchard plot analysis was tested to evaluate the binding sites of the PUF and stability constants of sorption were determined. On the basis of these parameters, the sorption mechanism was discussed. Among the foreign ions tested, Pb(II), Hg(II), cyanide and nitrite should be absent. The clean separation of Cd(II) from Zn(II) ions in the ratio 1:250, respectively, was achieved by column chromatography.     

2-HBR负载树脂分离富集金的研究及其分析应用

本文探讨了２－羟基苄叉罗丹宁（２－ＨＢＲ）负载树脂对金的吸附性能及用ＡＡＳ吸附金的酸效应、吸附动力学、吸附机理、吸附热力学、动态试验等。