Abstract For separation process design calculations such as distillation, absorption and extraction it is unconditionally necessary to have quantitative information on the mixtures in consideration, i.e. knowledge about phase equilibrium compositions, heats of mixing etc.

Abstract Crystallization is a far more attractive method for separation and purification of organic compounds than is often realized. When well applied, the advantages of crystallization as compared to distillation are: large separation effect, low energy consumption and low process temperature.

(1978). A review of: “Hypwfiltration and Ultrafiltration in Plate-and-Frame Systems R. F. Madsen Elsevier Amsterdam, New York, 1977; hardbound, 367 pages, $ 40.50”. Separation and Purification Methods: Vol. 7, No. 1, pp. 139-140.

Abstract When the ion exchange cellulose “Protion1” was used on a pilot plant scale to produce a re-usable water from a proteinaceous treated meatworks effluent2, it withstood such industrial handling without excessive degradation. A desire to exploit this characteristic of “Protion”, coupled with a wish to overcome problems like the blockage of downflow resin beds by fine suspended solids encountered in the meatworks effluent project, suggested using “Protion” in fluidised beds. However, since the introduction of batch fluidised bed processes seemed reasonably straightforward, it was decided instead to develop a truly continuous process in which “Protion” might have an even greater advantage over more fragile sorbents. Since continuous systems require a greater level of instrumentation and engineering skill than batch processes, it was later decided to apply the technique, not for effluent treatment but for the extraction of enzymes from protein broths It was thought that the greater product value in thi...

Abstract It has been widely recognized for many years that gases, vapors, liquids, and solutes permeate through non-porous polymer membranes by a solution-diffusion mechanism1–5. However, it was only ten years ago that it was first proposed6 that reverse osmosis might be quantitively described by this mechanistic model. The solution-diffusion model first published by Lonsdale, Merten and Riley6 has been applied with considerable success to describe a variety of systems but the cellulose acetate-water-inorganic salt system has received most attention due to its importance in desalination. It is widely accepted that this model not only describes the process of reverse osmosis but also represents an accurate mechanism in those cases where the membrane structure is truly dense, i. e. non-porous, with no imperfections - this condition refers only to the "active layer" in Loeb-type6 membranes.

Abstract Since the late Professor T. Svedberg began to apply centrifugal force for the study of colloid systems, progress in centrifugation has continued in two parallel directions. The first line of development has produced the analytical ultracentrifuge, which incorporates an optical system for the analysis of small amount of material while it is being centrifuged through a homogeneous medium (the solvent) under ideal conditions. The analytical centrifuge is now widely used not only to characterize molecular weight, but also to give insights into the size, shape, density and the base composition and activity of biopolymers and other macromolecules. The second line of development has produced the preparative centrifuge, which uses centrifugal force to sediment the solid phase of materials. The preparative centrifuge is a simpler instrument and does not have an optical system. However, recent rapid technical progress and development permit the preparative centrifuge not only to completely separate several or all of the components in a mixture, but also to perform analytical measurements. This versatile technique is known as density gradient centrifugation.

Abstract Since the initial studies of James and Martin1,2 gas chromatography has revolutionized separations in organic and biochemistry. The development of the gas chromatography of metallic species has been relatively slow in coming; however, the inherent advantages of extraordinary sensitivity, speed and ease of separating mixtures of closely related compounds, has promoted a recent surge of interest in the technique. In general, gas chromatographs are not conveniently operated at temperatures in excess of 350° C. This temperature requirement places severe limitations on the types of inorganic compounds that can be chromatographed. In most, but not all cases, the metal complex must exhibit avapor pressure of 0.1 to 1 mm of mercury in order to have a reasonable rate of gas-phase migration through the column3. To meet the requirement, the complexes must be unusually volatile and thermally stable in the chromatographic column. Metal compounds of suitable volatility are limited in number and include metal alklys, metal alkoxides, metal carbonyls, metal hydrides, metal halides, π-bonded metal complexes and β-diketonates. Furthermore, the compounds must be formed in quantitative yield to be of practical analytical utility. The metal halides and the metal β-diketonates are the only two of the above which meet all these requirements.

As a general rule the electrophoretic mobility of molecules and particles is solely governed by the potential at their surface of shear (ζ-potential) and does not depend on their size or shape. The...

Abstract Gas liquid and solid mixtures undergo a slight demixing in the presence of a temperature difference. This phenomenon, known as thermal diffusion, is illustrated in Figure 1 for the isotopes of neon in the gas phase and for isotopically substituted carbon disulfide in the liquid phase. The separation effect, which is quite small even for relatively large temperature differences, was of no practical significance prior to the invention by Clusius and Dickel of the thermogravitational thermal diffusion column in 19381. In the thermal diffusion column (Figure 2) the fluid is confined between closely spaced vertical walls maintained at different temperatures. A convection current is set up with the fluid rising along the hot wall and descending along the cold wall. Thermal diffusion takes place In the horizontal direction. The combined effects of vertical countercurrent thermogravitational circulation and horizontal thermal diffusion lead to large separations in the vertical direction. The equivalent of several hundred separation stages can be obtained in apparatus no more than a few meters in length.

Abstract Dialysers with membranes of the coil, plate, or capillary configurations are most commonly used in separation procedures. Inrecent years, there is the development of a new class of dialys is system in the form of semipermeable microcapsules (1,2,3, 4). It is the purpose of this paper to discuss this new dialys is system and to compare it with standard dialysers.