【摘要】 <正> 前言在制药工业和食品工业中,常常需要去掉体系中的诸如盐类的小分子物质,进而使其中的大分子物质得到纯化。如各种专一的蛋白酶、醣类和氨基酸等分开,在生物制品工业,人们从动、植物中提取许多具有生物活性物质,它们的含量很少,其特性往往被杂质所掩盖,必须经过一定的分离,将之提纯净化。更多还原

【Abstract】 In order to extracty and purit some valuable materials,washing filtration process is usually employed in pharmaceutical and food industries. Washing filtration is membrane sparating technic and also ultrafiltration process. Small molecular materials dissolved by solvent were permeated through membrane and removed with solvent from useful material Solvent,usually water,was added continuously to one side of membrane. The rate of adding water equals to it of filtrate.In this way,the permeable materials were diluted the retained macromolecular solution.Therefore, the separation between macromolecular and small molecular was improved and product is extracted and purified.更多还原