Metal (II) ion binding onto chelating exchangers with nitrogen donor atoms: Some new observations and related implications

摘要: Chelating exchangers with only nitrogen donor atoms exhibit some unusual properties in relation to metal ion uptake from the aqueous phase. Specifically, for these chelating exchangers, (a) increases an increase competing Ca{sup 2+} and Na{sup +} concentrations; (b) removal capacities remain almost unaffected at pH as low 1.0; (c) regeneration or desorption of ions ammonia is very efficient while acid ineffective; (d) both cations other anions can be removed simultaneously The foregoing behaviors are not observed all commonly used carboxylate, iminodiacetate, aminophosphonate functionalities. A molar-exchange model, where individual bind independently on molar basis, explain anomalous characteristics specialty exchangers. Because their properties, offer new application opportunities heavy-metals unattainable through