Second Report on Fabrication and Evaluation of New Ultrathin Reverse Osmosis Membranes

摘要

Promising new materials for reverse osmosis membranes have been developed. A dynamic-flow test cell has been constructed and tested--additional cells are being obtained. An osmosis cell was constructed to obtain basic data on new membrane materials. To show how the desalination properties of cellulose acetate are affected by the polymer structure, acetates of other polysaccharides have been prepared and tested in reverse osmosis. An entire class of new, high-performance desalination polymers resulted. Although these polysaccharide acetates were widely divergent in structure, all gave good salt rejection and all were within the same order of magnitude in water flux. Also, mixtures of these acetates, such as a 1:1 mixture of cellulose triacetate and xylan acetate, gave essentially the same desalination properties. Many of the results suggest that polymer morphology is, at best, a minor factor for water transport by cellulose acetate. Two of the materials, xylan acetate and beta-glucan acetate gave higher water flux than cellulose triacetate.