PROCEDURE FOR THE PREPARATION OF ASYMMETRIC PERMSELECTIVE CELLULOSETRIACETATE MEMBRANES AND APPLICATION OF SUCH MEMBRANES

摘要

An asymmetrical permselective cellulose triacetate membrane has outstanding properties for desalination of seawater by reverse osmosis. It is made by casting a solvent solution of the cellulose triacetate in a solvent mixture of at least 40% acetone, a solvent for the triacetate and a swelling agent for the triacetate. The swelling agent, preferably formamide, must be added as the last component of the solution. After exposing the cast solution to evaporation for 2-90 seconds, it is precipitated in cold water, and then optionally tempered at 50 DEG -100 DEG C. in water which may contain a modifying agent, and dried.