Phenanthrene sorption to environmental black carbon in sediments from the Song-Liao watershed (China)

Black carbon (BC) in ten contaminated sediments from the Song-Liao watershed, NE China, was isolated upon treatments using a combustion method at 375°C, and the isolates’ sorption isotherms for phenanthrene (Phen) were determined. All sorption isotherms were nonlinear and fitted well by the Freundlich model. A negative relation was found between Freundlich sorption nonlinearity parameter ( n values) and BC/total organic carbon (TOC) content of the original sediments ( r 2 = 0.687, p <0.01), indicating the dominance of BC in Phen sorption nonlinearity. The BC isolates from this industrialized region had n values of 0.342 to 0.505 and log K FOC values of 6.02 to 6.42 (µg·kg −1 ·OC −1 )/(µg·L −1 ) n for Phen. At a given C e , the BC had higher K oc value than the original sediments, revealing a higher sorption capacity for BC. BC was responsible for 50.0% to 87.3% of the total sorption at C e = 0.05 S w , clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.