溶剂挥发法制备萃取剂微胶囊

萃取剂微胶囊的制备是利用微囊化方法将萃取剂包覆起来 ,解决传统液液萃取中的两相相分散、相混合、相分离以及溶剂的损失和设备结构复杂等问题 .用简单易控制的溶剂挥发法成功制备了聚砜及聚苯乙烯材料包覆的多种萃取剂 (如磷酸三丁酯 ,2 乙基己基磷酸 ,三辛胺和Aliquat 336 )微胶囊 ,并考察了壁材和分散剂的选择对不同萃取剂进行包覆的影响 ,同时研究了搅拌速度和膜溶液组成对微胶囊的形态、萃取剂包覆量的影响 .结果表明 ,(1)用聚砜作壁材可以包覆磷酸三丁酯、2 乙基己基磷酸 ,而用聚苯乙烯可以包覆三辛胺、Aliquat336 ;(2 )对于不同的O W乳液体系 ,只有选择合适的分散剂 ,才能得到理想球形状、分散性好的微胶囊 ;(3)增大搅拌速度可以降低液滴尺度 ,从而减小微胶囊粒径 ;(4)膜溶液组成的影响则表现在两个方面 ,一是膜溶液的粘度和两相界面张力是除搅拌速度外微胶囊粒径的决定因素 ,二是膜溶液中壁材与萃取剂的比例优化时 ,才能得到萃取剂包覆量高的微胶囊 .

PREPARATION OF EXTRACTANT MICROCAPSULES BY SOLVENT EVAPORATION METHOD

To encapsulate extractants by method of microencapsulation can solve the problems of phase dispersion,phase mixing,phase separation,the leakage of extractant,as well as complicated structure of equipment in the extraction process.In the present work polysulfone and polystyrene as polymer materials were used to encapsulate the extractants such as TBP,D2EHPA,TOA,Aliquat 336 etc by means of solvent evaporation.The influence of shell materials,dispersants,stirring speed and composition of the organic phase has been investigated.The experimental results showed that TBP and D2EHPA were successfully encapsulated with polysulfone as the shell material while for the preparation of TOA and Aliquat 336 the shell material of polystyrene should be applied.The spherical shape and monodispersity of the microcapsules were related to the dispersion agent used in the O/W system.The mean diameter of the microcapsules decreased greatly with an increase of the stirring speed.Besides the stirring speed,the viscosity of polymer solution and the interfacial tension of working systems are the major factors that influence the size of the microcapsules.An optimal encapsulation efficiency of the microcapsules was reached when the content ratio of the shell material to the extractant in the polymer solution was optimized.