ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Past detailed studies of solute transport through reverse-osmosis membranes have been conducted only with simple salts. The present work with phenol was undertaken largely because of the practical observation that the transport of low molecular weight organics is much more rapid than that of the salts. Studies of phenol sorption from dilute aqueous solution indicate that the diffusion coefficient for phenol in water-saturated 39.8 wt.-% acetyl cellulose acetate is 9.6 × 10-10 cm.2/sec., and the equilibrium distribution coefficient between the acetate phase and water is 42. Thus, the diffusion coefficient is quite close to that measured for sodium chloride, and the higher permeability of the membranes to phenol can be attributed entirely to their greater sorption of this solute. In direct osmosis experiments performed with significant water flow a measurable interaction or positive coupling between water and phenol flows has been observed. Further evidence of flow coupling is derived from reverse osmosis experiments in which significant negative solute rejection is observed; i.e., the permeate is enriched in phenol by as much as 20%. It is shown that a solution-diffusion transport model is not adequate to rationalize the results, and a more complex transport model is apparently required.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1967.070110917
Permalink
