A comparative study of surface acid-base characteristics of natural illites from different origins

Optimization results indicated that both models could provide a good descri ption of the titration behavior for all aqueous illite systems in this stud y. The intrinsic acidity constants for the different illites were similar i n Model I, showing some generalities in their acid- base properties. Model I may be considered as a simplification of Model II, evident in the similar ities between the corresponding constants. In addition, the formation const ant for surface Al-Si species (complexes or precipitates) is relatively sta ble in this study. (C) 1999 Academic Press.