Halloysite is a clay mineral similar to kaolinite and can be found in soils and weathered rocks in different particle shapes and hydration states. Due to misfit between the SiO4 tetrahedral sheets and Al(OH)6 octahedral sheets, it may form tubular structure with the SiO4 tetrahedral sheets on the outer surfaces. The isomorphous substitution resulted in substantial cation exchange capacity (CEC). In this study, we tested the uptake of selected pharmaceutical compounds (PCs) by halloysite nanotubes (HNTs) under different physico-chemical conditions. The uptake capacity of these PCs were slightly lower than the CEC values of the HNTs, while the stoichiometric relation between the amounts of PC uptake and desorption of exchangeable cations supported cation exchange as the major mechanism for the uptake of PCs by the HNTs. The uptake of PCs was on the external surfaces of HNTs, whilst the surface area was not a limiting factor for the uptake of PCs. The finding from this study could extend the application of HNTs as a carrier for ionizable pharmaceuticals.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials