Characterizing Transport and Sorption in Ion-Specific Resin Columns Using Nuclear Magnetic Resonance (NMR) Imaging

Abstract

The goal of this work is to assess the physical transport properties of Gd through an ion exchange column while determining the sorption properties of the resin. By coupling the physical transport with the chemical sorption, further insight into the behavior of the ion exchange resin can be gained. NMR imaging provides a powerful, non-destructive, means to extract spatial information from complex systems on a near real-time basis. An important example is liquid flow through granular media. With the use of a chemically reactive NMR contrast agent, the chemical speciation can be traced along the physical flow path of the granular media. In this study, trivalent gadolinium (Gd 3+ ) was selected based on its chemical similarity to typical high-level waste components, 241 Am and 244 Cm, and for its paramagnetic contrasting abilities in NMR experiments. NMR imaging results of flow experiments are provided showing a characteristic flow phenomena and resin column loading profiles. ICP-AES data are provided to show resin ion exchange capacities (IECs) and breakthrough curves. The use of NMR imaging with a Gd 3+ tracer will lead to a better understanding of the transport and sorption properties of these ion-specific resins. This technique can be applied to other complex flow systems such as environmental transport.