Study Poorly-Ordered Natural Colloids and Nanoparticles.

Natural colloids and nanometer-sized particles in soils and sediments play the most critical roles in many geochemical processes that regulate the transformation and transport of nutrients, heavy metal, and organic compounds. Their importance has been well recognized by soil scientists and geochemists. Yet, the structures of these materials in general are still very poorly understood due to difficulties in the  interpretation of many types of data collected on them, such as X-ray diffraction, infrared spectroscopy, X-ray absorption spectra. This presentation will review progresses made by some new technologies such as total X-ray scattering and neutron scattering,  extended X-ray absorption  fine structure spectroscopy, and molecular modeling on the characterization of clay minerals and iron oxides. The main objective of the presentation is to stimulate discussion among soil scientists to adopt and to create new methods to study these poorly ordered materials in soils and environments.