- 1:10 PM

Controlling Zeolite Crystal Morphology Using Oil/Water/Surfactant Mixtures

Daniel F. Shantz, Department of Chemical Engineering, Texas A&M University, TAMU 3122, College Station, TX 77843-3122

This talk will summarize our recent efforts to synthesize zeolite crystals with controllable morphology using oil/water/surfactant/mixtures. The first part of the talk will summarize silicalite-1 growth in oil/water/surfactant mixtures at low temperatures (<368 K). Clear differences are observed between the materials formed in nonionic microemulsions [1,2] and syntheses using ionic surfactants [3,4]. The crystal morphology depends on the nature of the surfactant, and control experiments clearly show that surfactant adsorption on the growing crystal surface, not the confined space afforded by the microemulsion is central to the crystal habit obtained. The second part of the talk will highlight recent work on the growth of zeolite LTL rods, [5] a zeolite with a Si/Al ~ 1.5. In the presence of both cationic and nonionic surfactant/oil/water mixtures crystals that are highly anisotropic (L/D ~ 5 10 typically, with values as high as 45 observed) are formed, in contrast to the normal synthesis (L/D ~ 1.5 2). Given their high extra-framework cation density these materials appear to be promising candidates for the growth of nanowires arrays in the zeolite pore system.

[1] Lee, S., Shantz, D. F. Chem. Commun. 2004, 680-681.

[2] Lee, S., Shantz, D. F. Chem. Mater. 2005, 17, 409-417.

[3] Axnanda, S., Shantz, D. F. Microporous Mesoporous Mater. 2005, 84, 236-246.

[4] Lee, S., Carr, C. S., Shantz, D. F., Langmuir 2005, 21(25), 12031-12036.

[5] Carr, C. S., Shantz, D. F. Chem. Mater. 2005, 17(24), 6192-6197.