对透过的物质具有选择性的薄膜称为半透膜，一般将只能透过溶剂而不能透过溶质的薄膜称之为理想半透膜。当把相同体积的稀溶液和浓溶液分别置于半透膜的两侧时，稀溶液中的溶剂将自然穿过半透膜而自发地向浓溶液一侧流动，这一现象称为渗透。反渗透是渗透的一种反向迁移运动，是一种在压力驱动下，借助于半透膜的选择截留作用将溶液中的溶质与溶剂分开的分离方法.
參考答案:Through selective material on the film as semipermeable membrane. generally only through the solvent and solute film can not call it ideal semipermeable membrane. When a dilute solution of the same size and concentrated solution were placed on both sides of the semi-permeable membrane, dilute solution of the solvent through the semipermeable membrane and spontaneous natural solution to the strong side movements, a phenomenon known as infiltration. A reverse migration is the reverse osmosis infiltration campaign is a pressure-driven, semipermeable membrane role in the choice of means to retain separate from the solution of the solute and solvent separation.