Hydrophilic Black Carbon Soot for Aqueous Dispersion

THOMAS W. KIRCHSTETTER (1), Odelle Hadley (1), Jeffery Aguiar (2)

(1) Lawrence Berkeley National Laboratory, Berkeley (2) University of California, Davis

     Abstract Number: 751
     Last modified: May 14, 2010

Abstract
A reproducible black carbon that can, in laboratory experiments, be delivered in a manner that yields a constant and tunable concentration would be of great value to the atmospheric science community. It would assist in the evaluation of new measurement methods and in the comparison of existing methods for black carbon concentration and aerosol light-absorption coefficient. It would also benefit laboratory studies aiming to understand climate-relevant processes, such as the impact of mixing state on aerosol optical properties or the impact of black carbon on snow albedo.

At Lawrence Berkeley National Laboratory, we produce hydrophilic black carbon on Teflon membranes for the purpose of making aqueous dispersions. The black carbon forms a homogeneous and stable suspension – a hydrosol – as it is rinsed with water off of the Teflon membrane. The mass of black carbon in the water is easily determined by weighing the Teflon filter prior to and after rinsing. The hydrophilic black carbon can be stored on the Teflon membrane for several months prior to use. Likewise, the black carbon hydrosol is (electro-statically) stable for up to a year or longer.

A constant concentration of black carbon is produced from the hydrosol using a nebulizer (or a similar device) to create droplets and subsequently evaporating the water. The chemical and optical properties, the morphology, and applications of the black carbon generated this way will be presented.