Proton-exchanged AMH-3 was prepared by ion exchange of interlayer cations of the layered silicate AMH-3 using an aqueous solution of amino acid. Moreover, swollen AMH-3 was prepared by a procedure involving sequential intercalation of primary amine molecules following proton exchange. Structural characteristics of both AMH-3 derivative materials were investigated using characterization techniques such as XRD, SEM, TEM, NMR, FT-IR, TGA, and N2 adsorption. Both processes lead to structural changes and condensation of silanol groups located on the silicate layer surface. Proton-exchanged AMH-3 is an amorphous powder with the same particle size and shape as the original AMH-3 crystals. Due to the structural changes, swollen AMH-3 should be considered as a new layered silicate material rather than an intercalated phase. The swollen AMH-3 powder shows limited evidence for the presence of a nanoporous framework, suggesting that its use as a molecular sieve additive for improved selectivity nanocomposite membranes is worth exploring.
Bibliographical noteFunding Information:
Funding for this work was provided mainly by NSF (CTS-0327811). Additional support was provided by DOE (DE-FG26-04NT42119) and Pall Corporation. Joaquin Coronas acknowledges support from the Spanish Ministry of Education (Programa de Estancias de Profesores de Universidad of the Dirección General de Universidades, PR2004-0478), Sankar Nair from NSF (CTS-0437621), and Daniel F. Shantz from the Petroleum Research Fund of the American Chemical Society (Award 43942-AC10). We gratefully acknowledge Sandeep Kumar in our group for the TEM images of swollen AMH-3 particles.
- Ion exchange
- Layered silicate
- Molecular sieve