Posttreatment effects on pore size distribution of loeb-sourirajan-type modified cellulose acetate ultrathin membranes



The nitrogen gas adsorption isotherms at −195°C on modified cellulose acetate ultrathin membranes were measured, and the surface area of the pores was determined by the method employed by Cranston and Inkley. A relationship between reverse osmosis characteristics and the mean pore radius was correlated, and it was observed that any method (such as longer evaporation period, heat treatment, or reduction of swelling agent) reducing the mean pore radius to below 20–22 Å improves membrane characteristics of reverse osmosis separation significantly.