Chemistry: electrical and wave energy – Processes and products – Electrostatic field or electrical discharge
Patent
1987-01-27
1988-07-19
Niebling, John F.
Chemistry: electrical and wave energy
Processes and products
Electrostatic field or electrical discharge
204301, 204152, 2041824, 210650, B01D 1300, B01D 1302, C02F 144
Patent
active
047583207
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for separating solid particles or macromolecules contained in a solution. Its object is to improve a process usually called "electro-ultrafiltration" comprising filtering the pressurized solution through a semi-permeable membrane which is specific to the separation involved and in applying an electric field to reduce the concentration gradient in the immediate vicinity of the membrane. The invention also comprises apparatus for carrying out the process.
The technique of electro-ultrafiltration was recently developed from ultrafiltration techniques in which a pressure difference is applied to make the solution being treated cross a semi-permeable membrane of which the cut-off threshold is adjusted to the macromolecules to be retained for the range of 5,000 to 100,000 Daltons. However this concentration gradient (which still is called "concentration polarization" by the experts) quickly forms in the vicinity of the semi-permeable membrane when these techniques are used and restricts the flow density of the permeate and hence the separation efficiency. The technique of electro-ultrafiltration reduces this concentration gradient if the macromolecules are electrically charged by applying a DC electric field to the solution. The direction of this field is such that the macromolecules tend to move away from the membrane by electrophoretic migration. The following publications in particular describe this kind of process: concentration polarization in ultrafiltration"(Ultrafiltration membranes and applications, A. R. Cooper editor, Plenum Press, New York 1980). ultrafiltration for improved processing of Plasma Proteins" (Separation Science and Technology, 15, (8), pp 1491-1980), electro-deposition paint" (J. of Coating Technology, 54, (695), p 33-1982), electro-ultrafiltration for colloidal solution of proteins" (J. of Chemical Engineering of Japan, 16, (3), p 246-1983).
However this technique of electro-ultrafiltration incurs a serious, intrinsic drawback: according to the implications of the prior art, it is impossible to use several juxtaposed semi-permeable membranes in order to define adjacent compartments to increase the exchange area in the manner it is done in conventional ultrafiltration. No matter which the direction of the electric field, the decrease in the concentration gradient near a particular membrane would likely increase this gradient near two adjacent membranes because then the electric field would be pointing the wrong direction for these two, and the gain in efficiency achieved by the electric field on half the membranes would be wiped out by the loss in efficiency of the other membranes subjected to this field. In some of the equipment known, as alternation is introduced between semi-permeable ultrafiltration membranes and solvent-impermeable membranes (U.S. Pat. Nos. 3,905,886 and 4,043,896). Therein, one membrane out of two carries out the ultrafiltration in a single direction (the electric field being applied so as to reduce the gradient near the semi-permeable membranes). The function of the other membranes merely is to keep the compartments apart. The drawback of this equipment is that for constant bulk, the exchange surface is cut in half relative to a conventional ultrafiltration apparatus, whereby the significance of electro-ultrafiltration is mostly lost.
The primary object of the present invention is to improve the process of electro-ultrafiltration so as to combine the advantages of conventional ultrafiltration having serial semi-permeable membranes with those of electro-ultrafiltration having an applied electric field.
Accordingly the main object of the invention is to benefit both from large exchange areas at a given bulk and permanently increased efficiency.
The process of the invention makes it possible to separate electrically charged solid particles or macromolecules contained in a solvent, colloids contained in baths, charged particles suspended in a liquid etc. This process makes use of semi-permeable membranes which are specific for the s
REFERENCES:
patent: 2247065 (1941-06-01), Pauli et al.
patent: 3099615 (1963-07-01), Kollsman
patent: 3309301 (1967-03-01), Kollsman
patent: 3562139 (1971-02-01), Leitz
patent: 3870617 (1975-03-01), Bourat
J. M. Radovich, N. S., Mason, R. E., Sparks, "Coupling Electrophoresis with Ultrafiltration for Improved Processing of Plasma Proteins", Separation Science & Technology, 15, (8), pp. 1491-1980.
Aimar Pierre
Mahenc Jean
Sanchez Victor
Centre National de la Recherche Scientifique (C.N.R.S.)
Dutton, Jr. Harold H.
Niebling John F.
Starsiak Jr. John S.
LandOfFree
Process and apparatus for separation of solid particles or macro does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and apparatus for separation of solid particles or macro, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and apparatus for separation of solid particles or macro will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-595637