Sorption of hydrophobic organic contaminants to black carbons

Black carbons have been proposed as important sorbents in soils and sediments. Nguyen et al. used sorption isotherm data of added phenanthrene and 1,2,4-trichlorobenzene (TCB) to a diesel soot SRM 2975 to show that adsorption is the dominant mechanism for this particular soot. An extension of the work described by Nguyen et al. was presented and focused on quantifying the adsorption and absorption components of sorption to different chars and soots, using the combination of single solute sorption isotherm data from aqueous solution and pore size distributions estimated based on high-resolution nitrogen adsorption data. A clear trend was the lower degree of sorption isotherm nonlinearity for diesel soot SRM 1650b compared to that of SRM 2975 with both phenanthrene and TCB. The presence of 20% extractable native organic phase in one type of diesel soot (SRM 1650b) reduced adsorption at low contaminant concentrations but enhanced absorption at high contaminant concentrations. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).