摘要

Membrane separation at low temperatures is a favorable method for concentrating and purifying heat-sensitive biological molecules, for example, proteins. This results in that the production of an ultrafiltration membrane with long-term durability and low cost is receiving extensive attention. A new type of ultrafiltration membrane suitable for concentrating or separating proteins or macromolecules from small molecules such as salts or organic compounds is obtainable by directly mixing water glass solution with polyvinyl alcohol solution followed by soaking in aqueous H2SO4 solution. The molecular weight cut off of the ultrafiltration membrane was estimated to be > 36,000 and < 45,000 Da while its water permeability is reasonably high. The measured results of the critical mechanical properties, including tensile force, strength, length and elongation of the membrane indicated that its long-term durability should be good. Soaking the silica/polyvinyl alcohol membranes in 2 mol/L aqueous H2SO4 solution is very vital to improve the rejection rate of proteins investigated. The new and advanced preparation method of the membrane has a short, efficient and low cost operating process. The silica/polyvinyl alcohol membrane may also be applicable to the removal of microorganisms in water.