含羧基和吡啶基两性离子交换纤维的结构控制

Structure control of carboxyl/pyridine-containing amphoteric ion exchange fibers

采用X射线光电子能谱、红外、热失重-红外联用及扫描电镜等手段研究了含羧基和吡啶基两性离子交换纤维的结构,及其对金属离子和氨基酸的吸附分离特性.结果表明,两性离子交换纤维含有羧基和吡啶基,其总交换容量、阳/阴离子交换基团的比率以及纤维的表面形貌可通过选择共接枝单体对种类及其投料比来控制,从而控制两性纤维的吸附选择性.随着共接枝单体吡啶组分含量的增加,阴离子交换容量逐渐上升,阴离子交换基团占总交换基团的比率也随之增加,两性纤维的表面形貌综合了两种单体单组份接枝时的特征.由于吡啶和羧基的协同作用,两性纤维对Cu2+有很大的吸附量,而且当酸碱两种基团含量接近时,协同作用更强.

The structures of carboxyl/pyridine-containing amphoteric ion exchange fibers were investigated, and the adsorption properties of the obtained fibers for metal ions and amino acids were assessed. The experimental results showed that the amphoteric ion exchange fibers consist of carboxyl and pyridine groups. Their total ion exchange capacity, the rate of cationic and anionic groups, and the morphology could be controlled by changing the type of monomers and the load ratio of acidic and basic monomers. In addition, the competitive adsorbability of the amphoteric fibers could be controlled by the structure of fibers and the adsorption conditions. When the feed content of pyridine monomer increases, the anionic exchange capacity and the ratio of anionic groups to total capacity of the resultant fibers increase. The morphology of the amphoteric fibers was synthesized with both the textures of poly-vinyl-pyridine and poly-acrylic (or methacrylic) acid which were produced in single component grafting system. The prepared amphoteric fibers possess high adsorption capacity for Cu2+ due to the coordination action of pyridine and carboxyl groups. When the contents of acidic and basic groups were close to each other, the coordination action for adsorption was enhanced.