It is joyful having Prof. Conte today to share his work of relaxometry application on environmental science.
In the field of soil chemistry and environmental chemistry, field-cycling NMR relaxometry has not yet been a well-recognized approach. Hence, Prof. Conte has shared two of his works to introduce the capability of field-cycling NMR in applications of soil chemistry and environmental chemistry. For scientists who are interested in environmental science, relaxometry can explore more and open different windows of molecular dynamics in soil chemistry.
Fast field cycling NMR relaxometry is becoming more and more a very useful technique to unveil the molecular dynamics of complex systems. In the recently published paper from Lo Meo et al. (2020) J. Phys. Chem. B, 124: 1847−1857, the authors used FFC NMR relaxometry to study the properties of synthetic nano-sponges. These are molecular systems which can be applied in many different fields: from drug delivery to environmental remediation. It is noteworthy that nano-sponges ability to trap organic and inorganic materials strongly depends upon their pore size and distribution. However, it is also known that the typical techniques used to measure nano-sponge porosity fail in their aim. Lo Meo et al. suggested the use of FFC NMR relaxometry to define a soft matter connectivity index which appeared to be very suitable for the understanding of nano-sponge trapping properties.
Nuclear magnetic resonance (NMR) techniques are largely employed in several fields. As an example, NMR spectroscopy is used to provide structural and conformational information on pure systems, while affording quantitative evaluation on the number of nuclei in a given chemical environment. When dealing with relaxation, NMR allows understanding of molecular dynamics, i.e., the time evolution of molecular motions. The analysis of relaxation times conducted on complex liquid–liquid and solid–liquid mixtures is directly related to the nature of the interactions among the components of the mixture. In the present review paper, the peculiarities of low resolution fast field-cycling (FFC) NMR relaxometry in soil science are reported. In particular, the general aspects of the typical FFC NMR relaxometry experiment are firstly provided. Afterwards, a discussion on the main mathematical models to be used to “read” and interpret experimental data on soils is given. Following this, an overview on the main results in soil science is supplied. Finally, new FFC NMR-based hypotheses on nutrient dynamics in soils are described...