Environmental NMR: Fast-field-cycling Relaxometry

Abstract

Fast-field-cycling (FFC) NMR relaxometry deals with the variation of the spin–lattice relaxation times (T1) in a complex system, as the strength of the applied magnetic field is changed. Information about molecular dynamics can be achieved. Until now, only model theories for FFC NMR relaxometry have been developed for polymer and material sciences. Just a few applications have been performed in the environmental sciences. These mainly deal with soil porosity, rock permeability, biomass transformations, and natural organic matter dynamics. Further, FFC NMR relaxometry can also be applied to monitor the environmental fate of contaminants, to understand the dynamics of nutrients at the soil–plant interface, and to evaluate reaction mechanisms in heterogeneous catalysis for the development of green reactions. This article summarizes the advances of the technique in environmental investigations and describes the tools used to monitor dynamics of organic and inorganic molecules in environmental compartments.