Acta Phys. -Chim. Sin. ›› 2002, Vol. 18 ›› Issue (07): 609-612.doi: 10.3866/PKU.WHXB20020708

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Ion Replacement Mechanism of Alginate-Chitosan-Alginate Gels

Chen Yi-Qing;Sun Duo-Xian   

  1. School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072
  • Received:2001-11-12 Revised:2002-02-28 Published:2002-07-15
  • Contact: Sun Duo-Xian E-mail:tdxsun@eyou.com

Abstract: 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.

Key words: Ion replacement gels, Alginate, Chitasan, Replacement mechanism, Mobile boundary model