Theory Of Concentration Polarization Research Articles

Modelling of Plasma-Separation through Microporous Membranes

Available mathematical models of ultrafiltration have been used to predict changes in maximum plasma filtration rate with wall shear rate for given filters and blood properties. We have done many plasmapheresis experiments in vitro, using hollow-fiber filters (500-1000 cm2) and fresh bovine blood collected on ACD or heparin. The comparison between predicted and experimentally obtained filtration rates was good for models based on the concentration polarization theory and lift velocity theory. In other experiments with pulsatile inlet flow we found that plasma filtration rate increased by 20 to 50% compared to non-pulsatile conditions. These results are in good agreement with the modified model of ultrafiltration incorporating pulsating flow. This paper presents relationships between plasma filtration velocity (steady and pulsating flow) and hemolysis limit as a function of wall shear rate and filter size.

Hyperfiltration studies V. Salt rejection of membranes by a concentration polarization method

A method was developed for rapid measurement of the salt rejecting characteristics of hyperfiltration membranes based on the theory of concentration polarization in an unstirred system. A piston forces solution through a cylinder (an adapted one cc tuberculin syringe) sealed at one end by a membrane. The transmission rate of the membrane and the concentration of the effluent are measured and the concentration-flux curves compared with those computed theoretically through solution of the time-dependent diffusion equation. Results have been obtained that agree well with theory and also with other experimental observations.

On the Polarization of the Manganese Dioxide Electrode

Experiments on the cathodic polarization and the potential recovery of electrodeposited on platinum are described. It is shown that at low current densities and pH 7.5 the shape of the potential‐time curves is in very good agreement with that predicted from the Coleman‐Scott theory of concentration polarization involving the solid phase of the electrode.