Polyfunctionality of resin carboyxl sites in ion exchange with alkali metal ions

✍ Scribed by Hiroki Tamura; Masashi Kudo; Ryusaburo Furuichi

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 546 KB
• Volume: 271
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)80059-t

✦ Synopsis

The ion-exchange behavlour of a weak acid-type cation-exchange resin with alkah metal ions was obtained as a function of pH by tltratlon The behavlour was analysed with a model that assumes that the resm has two types of carboxyl sites (I and II) with different reactlvltles (polyfunctlonahty) and that the ion exchange at each site IS suppressed steadily with progress of Ion exchange owmg to electrostatic lateral mteractlons between the species m the sohd/solutlon interphase The Ion-exchange parameters m the model were determmed by multi-parametnc curve fitting The values indicate that the type I sites are much more reactwe than the type II sites and are more subject to suppresslon The polyfunctlonahty was ascrlbed to the micropore structure of the resin the type I sites are distributed m under pores where hydrated Ions can be adsorbed electrostatically with larger lateral mteractlons and the type II sites m narrower pores where dehydrated Ions are adsorbed by formmg coordmatlon-type chemical bonds with smaller lateral mteractlons The activity coefficients of interphase species are discussed m terms of the electrostatic lateral mteractlons between these species