Consequently, precise numerical data on the various interfacial forces in membrane-solution systems may lead to some valid criteria of preferential sorption in reverse osmosis.
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Conclusions
T h e reverse osmosis technique is applicable for the separation of substances in nonaqueous solutions. Hydrocarbons tend to collapse the porous structure of the cellulose acetate membranes used; hence, for feed mixtures containing hydrocarbons, some other type of membranes will have t o be developed for reverse osmosis application. For a t least some organic feed solutions, such as alcohol-hydrocarbon mixtures containing more than about 25 mole 70 alcohol, porous cellulose acetate membranes of the type used in this work appear sufficiently good for consideration for industrial applications. I n view of the changing pore structure of the membrane in contact with organic feed solutions, the membrane-solutionoperating systems used could not be specified precisely as done (Sourirajan and Kimura, 1967) for aqueous solution systems and cellulose acetate membranes. Consequently, the performance data given in this paper have mainly relative significance, and do not represent limiting values obtainable in reverse osmosis systems involving organic liquid mixtures.
mounted i n ' t h e reverse osmosis cell, and A. G. Baxter and Lucien Pageau for their valuable assistance in the progress of these investigations. One of the authors (J. K.) thanks the National Research Council of Canada for the award of a postdoctoral fellowship. Literature Cited
Breitenbach, J. W., Forster, E. L., Makromol. Chem. 8, 140 (1952). Burrell, H., O f i . Dig., Federation Paint Varnish Prod. Clubs 1955, 726. Ghosh, S. K., Rawat, B. S., Indian J . Technol. 4, 62 (1966). Hildebrand, J., Chem. Reu. 44, 37 (1949). Kopetek, J., Sourirajan, S., Can. J . Chem. 47, 3467 (1969). Loeb, S., Sourirajan, S., Aduan. Chem. Ser., No. 38, 117 (1963). Loeb, S., Sourirajan, S., U. S. Patent 3,133,132 (May 12, 1964). Small, P. A., J . Appl. Chem. 3, 71 (1953). Sourirajan, S.,Nature 203, 1348 (1964). Sourirajan, S., Govindan, T. S., First International Symposium on Water Desalination, Washington, D. C., October 1965, Office of Saline Water, U. S. Department of the Interior, Vol. 1, pp. 251-74. Sourirajan, S., Kimura, S., IND. ENG. CHEM. PROCESS DESIGNDEVELOP.6, 504 (1967).
Acknowledgment
The authors are grateful to W. S. Peterson and W. L. Thayer for the design and construction of the stirrer
RECEIVED for review August 16, 1968 ACCEPTED October 9, 1969 Issued as N.R.C. No. 11126
REVERSE OSMOSIS SEPARATION OF SOME INORGANIC SALTS IN
AQUEOUS SOLUTION CONTAINING MIXED SOLUTES WITH A COMMON ION J.
P .
A G R A W A L
A N D
S .
S O U R I R A J A N
DiGision of Chemistry, National Research Council of Canada, Ottaua, Canada A simple method for predicting the performance of Loeb-Sourirajan type porous cellulose acetate membranes for low concentrations of mixed solutes in aqueous feed solution systems involves two or more inorganic salts with a common ion. The method requires only data on membrane specifications and the applicable mass transfer coefficient correlation for the corresponding single solute systems.
THE transport
equations and correlations of reverse osmosis experimental data using the Loeb-Sourirajan type porous cellulose acetate membrane for aqueous feed solutions containing one inorganic solute only have been discussed extensively (Agrawal and Sourirajan, 1969; Kimura and Sourirajan, 1967). The extension of the Kimura-Sourirajan analysis to mixed inorganic solute systems is complicated by the general nonavailability of the applicable osmotic pressure data, and the possibility of ionic interactions in such systems. Many natural waters 12
and industrial aqueous solutions contain more than one inorganic solute. The application of reverse osmosis for the separation and fractionation of such mixed solutes is of great practical interest. Hence the development of suitable methods for predicting membrane performance for such mixed solute feed systems is an area of fundamental importance in reverse osmosis transport; from this point of view, the available data on the subject (Erickson, 1966; Sourirajan, 1963) are only qualitative in scope. This paper presents some experimental data for the lnd. Eng. Chem. Process Des. Develop., Vol. 9,No. 1, January 1970
Table I. Membrane Specifications
Film type. CA-XRC-18 Operating pressure. 1500 p.s.i.g.
Film -VO. 1
1c
2 2A
2B
2c :3
:3B
Downloaded by FLORIDA STATE UNIV on September 9, 2015 | http://pubs.acs.org Publication Date: January 1, 1970 | doi: 10.1021/i260033a003
(3c 4B 4c 12 12A 12c
12E 1:i 1:JA 13C l:iE 16
16A 16B l6C 1611 16E :3 1
;3:3
A x IO' G Mole H,O Sy. Cm. Sec. Atm.
AVaCI
1.202 1.186 2.147 1.920 1.920 2.056 2.708
2.02 1.70 21.86 24.00 22.70 21.30 62.90 89.50 6.3.50 44 1.O 336.0
2.290 2.550
3.3:30 3.850 2.712 2.614 2.613 2.600 2.4
