HOW HETEROGENEOUS ARE THE SURFACES OF ENVIRONMENTAL BLACK CARBONS?: INSIGHTS FROM ION-PROBE FLOW ADSORPTION MICROCALORIMETRY

Department of Geography and Geology

The University of Southern Mississippi

Black carbons exhibit variable surface properties and environmental behavior due to differences in formation conditions and feedstock chemistry. We used a novel technique (ion-probe flow adsorption microcalorimetry) and a logistic modeling approach to characterize the heterogeneity of black carbons based on the distribution of acidic functional groups on their surfaces. The black carbons studied were produced from wood and grass that dominate the Gulf Coast region of the US. Our results show that, compared to wood, black carbons formed from grasses are generally more acidic (lower average pK_a) and had a broader array of carboxyl functional groups on their surfaces. Our presentation will discuss the significance of these findings in the context of facilitated transport of contaminants and the precipitation/dissolution of minerals in fired impacted areas.