A study on the preparation of polyvinyl alcohol thin-film composite membranes and reverse osmosis testing

摘要

Thin-film composite membranes were prepared by coating porous polysulfone membranes with a polyvinyl alcohol layer and further cross-linking its surface. Aldehydes, dialdehydes and malic acids were used as cross-linking agents. The effects of additives to the PVA solution, of solvents used for making PVA solutions, and of alcohols used for the membrane post-treatment on the reverse osmosis performance were investigated. The effect of PVA solution coating, drying and heat-treatment on the water permeability was also studied without cross-linking. It was found that heat-treatment had the strongest effect on the reduction of the water permeability. Hence, it was attempted to use cross-linking agents that could react at room temperature. Attempts were also made to carry out the cross-linking reaction at the cross-linking solution/PVA layer interface by dissolving cross-linking agents in hydrophobic solvents.