Aggregation kinetics of multiwalled carbon nanotubes in aquatic systems

COLL 390

Navid B. Saleh, navid.saleh@yale.edu1, Lisa Pfefferle, lisa.pfefferle@yale.edu2, and Menachem Elimelech, menachem.elimelech@yale.edu2. (1) Department of Environmental Engineering, Yale University, New Haven, CT 06520-8286, (2) Department of Chemical Engineering, Yale University, P. O. 06520-8286, New Haven, CT 06520-8286
Carbon nanotubes (CNTs) have a very widespread potential for application among the emerging nanomaterials, due to their unique physicochemical properties. There has been lack of studies understanding the fate and transport of CNTs in the environment. A systematic study of CNT aggregation kinetics is essential in order to predict fate of CNTs in natural environments. Effects of change in solution ionic strength and composition (Na, Ca, Mg), pH (3, 6, and 9), and presence of humic matter on aggregation kinetics of multi-walled carbon nanotubes (MWNTs) were evaluated in this study. Detailed characterization of the MWNTs was done using Raman scattering (for state of defect), thermo gravimetric analysis (for metal impurities), transmission electron microscopy (for length and diameter distribution), Fourier transformed infrared spectroscopy (for functional groups), and electrophoretic mobility (for surface charge). The aggregation kinetics of MWNTs were consistent with classical DLVO theory of colloidal stability in presence of Na, Ca, and Mg salts. Humic acid effectively stabilized the MWNT by steric interactions.
 

The Physical Chemistry of Environmental Interfaces
2:00 PM-6:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 225, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008