Nanoscience and nanotechnology have potential use in environmental applications. In collaboration with Professor Sarah Larsen (Chemistry), we are investigating nanocrystalline zeolite materials as new adsorbents and catalysts for use in environmental remediation, environmentally benign synthesis and the decontamination of chemical warfare agents. Zeolites are crystalline, aluminosilicate molecular sieves with pores of molecular dimensions. Zeolites can be synthesized with a wide range of pore sizes and topologies and are used in applications such as catalysis and chemical separations. The zeolite chemical composition, framework topology and pore size can be varied to control selectivity and reactivity. Nanocrystalline zeolites are zeolites with particle sizes less than 100 nm. These materials may be particularly useful in environmental applications due to the small crystal sizes and large internal and external surface areas. We are currently focused on using nanocrystalline zeolites in the decontamination of chemical warfare agents (CWAs). Finding new methods for CWA decontamination is a high national priority. Current research shows that nanocrystalline zeolites may be promising for this application.

In the case of the environmental remediation of NOx, nanocrystalline zeolites have been shown to be more effective in the selective catalytic reduction (SCR) of NOx with urea. Scheme below shows the mechanism for this reaction which involves NOx storage in the internal pores and reaction on the external surface of the nanoparticles.

Scheme. (a) SEM image of nanocrystalline NaY zeolite (scale bar = 100 nm), (b) a nanocrystalline zeolite particle with a crystal size of 23 nm, and (c) supercages (cycles) of zeolite Y interconnected to each other. The internal surface of nanocrystalline zeolite provides sites for NOx storage (as NO₂^- and NO₃^-) and minority of the SCR reactions, the external surface provides sites for additional NOx storage (as NO₃^-) and majority of the SCR reactions. Nanocrystalline alkali zeolites are classified as improved SCR catalysts.