海藻酸-壳聚糖-海藻酸凝胶离子取代机理

Ion Replacement Mechanism of Alginate-Chitosan-Alginate Gels

研究了海藻酸-壳聚糖-海藻酸(ACA)凝胶的离子取代机理.光学显微镜照相法证实ACA离子取代过程中溶胶-凝胶相界面的存在.动边界模型描述ACA离子取代凝胶对二价离子的取代动力学过程,结果表明,模型可靠.离子取代凝胶对二价离子的取代属于颗粒扩散控制机理.与离子交换树脂比较,ACA离子取代速率要快得多,ACA离子取代过程不同于传统离子交换树脂离子交换过程,它是金属离子在溶胶凝胶相转移过程中的取代过程;ACA是一种崭新的离子移变凝胶型离子吸附剂.

Alginate Chitosan Alginate(ACA) ion replacement gels are a novel ion adsorbent and are hopeful to be used to cure human toxicosis metallicus.In this paper,ion replacement mechanism of ACA on Pb2+was studied.Sol gel phase interface of ion replacement process of ACA was observed by optical microscope photo.On the basis of it,mobile boundary model (MBM) was used to describe ion replacement process.The results show that the model has high reliability.Ion replacement process was controlled by intraparticle diffusion control (PDC)(to see Fig.3).The chelating ion exchanger D418 and macropore acrylic resin D113 were studied for comparative analysis.The results show that ACA ion replacement gels has much faster ion exchange velocity than D418 and D113 resin and the two ion adsorbents have different ion replacement mechanism.Ion replacement of ACA is a sol gel phase transition process.