Abstract

Confirmation of the Nanopore Inner-Sphere Enhancement (NISE) Effect Using NMR Spectroscopy and Calorimetry

(1) Daniel R. Ferreira*, Department of Plant Science and Landscape Architecture, University of Connecticut

daniel.ferreira@uconn.edu

(2) C.P. Schulthess, Department of Plant Science and Landscape Architecture, University of Connecticut

c.schulthess@uconn.edu

            Adsorption experiments carried out on four zeolite minerals with Na, Ni, K, and Ca have shown that nanopores less than approximately 0.5 nm in diameter are capable of dramatically impacting the retention of cations.  This Nanopore Inner-Sphere Enhancement (NISE) effect can create counterintuitive adsorption scenarios where monovalent ions adsorb more strongly than divalent cations.  Experiments using nuclear magnetic resonance (NMR) and calorimetry have been undertaken in order to confirm the existence of an adsorption mechanism where monovalent ions form inner-sphere complexes while divalent ions form outer-sphere complexes under the same constrained conditions.