ABSTRACT
Nitroaromatic compounds (NACs) are widely used as pesticides, explosives, solvents, and intermediates in chemical syntheses. NACs and their degradation products pose a potential threat to ecological and human health because they are toxic environmental contaminants commonly found in soil and subsurface environments at elevated concentrations. At a site in Texas, for example, soil concentrations of NAC contaminants in excess of 75,000 mg/kg have been reported and have been detected at depths of greater than 30 meters at concentrations above human health exposure limits (1). In general, NACs degrade relatively slowly in the environment (2,3). Recent evidence has shown that certain NACs have a high affinity for certain types of clay minerals, and this may contribute to their recalcitrant behavior (4-11). This chapter will examine the chemical mechanisms that govern NAC-clay interactions from two perspectives. First, we will examine the properties of the clay surface that contribute to NAC sorption. Second, the chemical and physical properties of the NAC solute that influence sorption will be examined.
