Environmental black carbon (BC) is believed to be an important adsorbent of organic pollutants. In this study, we examined the effects of changes in surface properties and adsorbate structure. A series of apolar compounds (cyclohexane, 1,2-dichlorobenzene, 1,4-xylene, 1,2,3,5-tetramethylbenzene, 1,3,5-triethylbenzene) and a series of polar compounds (o-cresol, 4-nitrotoluene, 2,4-dinitrotoluene, and 2,4,6-trinitrotoluene) were sorbed from aqueous solution to maple wood char prepared under five thermochemical conditions. Two chars were prepared in air at 340 degrees C (C340) and 400 degrees C (C400). A subsample of C400 was treated with H2 in the presence of a supported Pt catalyst at 500 degrees C (C400-H) to remove surface O. Another was treated under N2 at 500 degrees C (C400-N) to serve as a control for C400-H. The reduced C400-H was further oxidized in air at 340 degrees C to reintroduce O (C400-H-A). The five chars vary in O content (26.1, 22.3, 4.2, 20.8, and 18.6 wt %, respectively) but show only minor differences in surface area and pore size distribution on the basis of N2 and CO2 adsorption analysis. These chars provide a basis for rationalizing sorption intensity as a function of sorbate molecular structure and surface chemistry. The following conclusions were drawn. (1) Polar interactions with surface O functional groups are not a significant driving force for adsorption. (2) When isotherms are adjusted for solute hydrophobicity (n-hexdecane-water partition coefficient), sorption intensity of the polar compounds is greater than that of the apolar compounds, possibly because of pi-pi EDA interactions of the polar compounds with the basal plane of the graphene sheets. (3) The largest test compounds show steric exclusion from a portion of the adsorption space available to the other compounds. (4) Removal of O functionality by hydrogenation enhances sorption intensity of polar and apolar compounds, alike by reducing competitive adsorption by water molecules.