Two objectives of this study were to measure the diffusion coefficients for Oxygen in three dilute polymeric aqueous solutions (Sodium carboxymethyl cellulose, Hydroxyethyl cellulose, Poly Vinyl Alcohol) under flow condition, and to investigate the influence of shear rate on diffusivity.
The wetted wall column was used for these objectives and the concentration of physically absorbed oxygen was measured using the Winkler titration.
The diffusivity of approximately pure Oxygen (minimum purity 99.99%) into distilled water was measured and found to be equal to $1.6×10^{-5}$㎠/sec at 20℃ which is in the range of values reported in literature.
It was found that diffusivity is a function of concentration and types of polymer, but the effect of viscosity of solution on diffusivity may not be the dominant one.
For Sodium C.M.C., the enhancement of diffusivity was found within the polymer-concentration range used (002-0.1wt%) and diffusivity was largest when the polymer-concentration was 0.1wt%.
$D/D_{water}$ = 1.11, Sodium C.M.C. 0.1wt%
In the case of H.E.C. solution, the diffusivity ratio varied from 1.0 to 0.87 as the H.E.C. concentration increased from 0.1wt% to 0.3wt%.
The diffusivity ratio for P.V.A. solution was always less than 1.0.
Taken account of the errors of the experiment, diffusivity was constant with respect to the change of the shear rate at the wall in the studied range of flow rate of solutions.
