摘要:

The contribution of the methylene group to the distribution coefficient (Δ logKD/CH2) has been obtained for 38 different solvents. For nonpolar solvents Δ logKD/CH2is in the range 0.60 to 0.64, whereas for polar solvents it is in the range 0.33 to 0.58. Attempts have been made to correlate group values with solvent polarity, and it is found that the solubility of water in the organic solvent phase has a profound effect. Equations are derived from the three-suffix Margules equation for a ternary system that relate Δ logKD/CH2to mole fraction solubility of water. The agreement between theoretical and experimental values is good for the case of alcohol solvents. Correlations with the empirical solvent polarity parameter of Reichardt are also examined.

ISSN:0037-2366    

DOI:10.1080/00372367508057064

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The effects of membrane separation parameters using liquid/liquid dialysis under idealized conditions and using hollow fiber geometry were calculated with the aid of a computer. These calculations were carried out for both single stage and multiple stages. Membrane separation parameters include the intrinsic properties of the membrane, the nature of the dialysis solvents, the flow rates of both feed and solvent streams, and the dimension of the hollow fiber. It was concluded that an efficient process using liquid/liquid dialysis requires a membrane with a high intrinsic permeability constant and a reasonable separation factor, as small an inner radius of hollow fiber as is practical, and a dialysis solvent with an acceptable activity coefficient for the key species and a flow rate suitably coupled to that of the feed.

ISSN:0037-2366    

DOI:10.1080/00372367508057065

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The influence of ion exchange capacity and total concentration of ions of different valences on the width of the working zone in a chromatographic column was analyzed by means of a theoretical investigation of the mathematical relations between the equations of the Glueckauf theory and equations of the law of mass action.

ISSN:0037-2366    

DOI:10.1080/00372367508057066

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The electrophoretic behavior of 19 metal ions on thorium phosphate papers is described. Seven background electrolytes were used for these studies to allow different time intervals. On the basis of the differential mobilities of the metal ions, which depend on the ion exchange properties of thorium phosphate and the nature of the complexes formed with the electrolyte, some important binary, ternary, and quaternary separations have been achieved.

ISSN:0037-2366    

DOI:10.1080/00372367508057067

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Particles of the size of living cells are too big to be separated in stabilizing media such as gels. The separation thus has to be done while they are freely suspended in a buffer contained in a vessel of appropriate shape. The major two disturbing factors under these conditions are cell sedimentation and electroosmotic backflow along the walls of the vessel.

ISSN:0037-2366    

DOI:10.1080/00372367508057068

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The principles, history, types, and applications of isoelectric focusing are presented. Also discussed are the theoretical aspects, electrooptical scanning, methodological parameters, and apparent physical constants. The lack of suitable carrier ampholytes is the primary reason why isoelectric focusing has not reached its full potential.

ISSN:0037-2366    

DOI:10.1080/00372367508057069

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Anions are selectively separated and concentrated from dilute aqueous solution by foam fractionation. Selectivity coefficients are established from steady-state equilibrium data (solution concentrations 10−4to 10−3M) for SCN-, I-, ClO3-, NO3-, BrO3−, and NO2−, each vs Br−, with the quaternary ammonium surfactant modeled as a soluble anion exchanger. Studies are reviewed on the foam separation of Re(VII), Mo(VI), and V(V) oxyanions; Au(I), Ag(I), Ni(II), and Co(III) cyanide complexes; and Pt(IV), Pd(II), and Au(III) chloro complexes. In a five-component system, the oxyanions of Re(VII), Mo(VI), Cr(VI), W(VI), and V(V) are foam fractionated from 10−6Msolutions with the cationic surfactant, hexadecyldimethylbenzylammonium chloride. In the batch, time-dependent experiments, the metals are monitored by radiotracers and gamma radiation spectrometry. At pH 6.0 and a chloride (NaCl) concentration of 10−2M, and at pH 2.0, adjusted with HCl, Re(VII) and Mo(VI) oxyanions can be separated completely from Cr(VI), W(VI), and V(V) oxyanions. The selectivity sequences are discussed in terms of acid-base equilibria and in terms of the absolute partial molal entropy of each anion in aqueous solution, as a measure of surfactant cation-anion interaction.

ISSN:0037-2366    

DOI:10.1080/00372367508057070

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Separation of various chemical components from each other is often the most difficult step in analytical procedures. The problems attached to separation become further magnified when the species concentations are extremely low. A group of techniques that has proven useful especially in dilute solutions for separating and concentrating metallic as well as nonmetallic ions and complexes, proteins, microorganisms, particulates, etc. is the adsorptive bubble separation techniques. Minerals have indeed been treated using some of these techniques for decades. The success of these processes is primarily dependent upon differences in the natural surface activity of various species or particulates in the system or in their tendency to associate with surfactants. The efficiency of the process is determined by such variables as solution pH, ionic strength, concentration of various activating and depressing agents, and temperature. A proper control of variables offers an opportunity to separate a variety of metallic and nonmetallic species and particulates. In this paper the principles governing various foam separation techniques, particularly froth flotation, are presented along with the recent results on the role of variables that can be controlled to achieve complete removal of species and particulates for analytical purposes.

ISSN:0037-2366    

DOI:10.1080/00372367508057071

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0037-2366    

DOI:10.1080/00372367508057063

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor