Nanosystems, such as nanocrystals and nanopores are ubiquitous in geological environments, especially in the critical zone where fluids meet the solid earth. Geochemical reactions and processes in nano-systems are greatly different from those in macroscopic bulk systems. Several department faculty are involved in research that deals with nanosystems.

Current research in Huifang Xu’s program includes studies of the relationship among morphology, size, reactivity and stability of nano-crystals; chemical reactions (with focus on sorption, desorption, precipitation, dissolution, and replacement reactions) in nanoporous environments; self-assembled nano-structures in the earth systems; and nano-structured materials for environmental management, such as removals of U, Tc, As, perchlorate, and dyes.

Current research in Eric Roden’s program includes studies of enzymatic reductive dissolution of nanoparticulate Fe(III) oxide phases; reductive precipitation of nanoparticulate uranium and other trace/contaminant metals; and enzymatic oxidation and phase conversion of ferrous iron-bearing minerals. Studies are conducted in both mineralogically defined systems as well as physically and chemically heterogeneous natural soil and sediment materials.

Current research in Nita Sahai’s program includes studies of toxic arsenic remediation by coprecipitation of phosphate and oxyhydroxide phases; biomimetic nanosilica synthesis by the catalytic action of amine functional groups that mimic enzymes in diatoms and sponges; formation/disruption of cell-membrane phospholipid bilayers at oxide surfaces, development of structure-activity relationships to predict the hydroxyaptite-nucleating ability of oxide- and silicate-based bioceramics and bioglasses that are used as prosthetic, orthopedic and dental implants; and understanding the role of specific proteins in nucleating hydroxyapatite in human bones. A combination of experimental and modeling techniques are used, including aqueous analytical methods (e.g. ICP-AES, UV-VIS, AA), calorimetry, Infra-Red, Raman and NMR spectroscopy, Atomic Force Microscopy, Electron Microprobe and High-Resolution Transmission Electron Microscopy, quantum chemical molecular orbital calculations, molecular mechanics and molecular dynamics simulations. Professor Sahai’s program includes active collaborations with faculty in the Departments of Geology and Geophysics, Chemistry, Soil Science, Biochemistry, and the Environmental Chemistry and Technology Program (ECT) at University of Wisconsin. Professor Sahai has appointments in Geology and Geophysics, and affiliate appointments in Chemistry and ECT.

For comments, suggestions or accessibility issues please e-mail the Webmaster Dept. of Geology & Geophysics, University of Wisconsin-Madison 1215 W Dayton St. Madison WI 53706. Tel: (608) 262-8960. Fax: (608) 262-0693