Effect of black carbon on sorption and desorption of phosphorus onto sediments

Abstract

The sorption behavior of phosphorus onto sediment was investigated with the addition of BC derived from incomplete biomass combustion (PC). The sorption kinetic curves of phosphorus onto PC and sediment could be described by a two-compartment first order equation, and the sorption isotherms fit the Freundlich model well. With increasing amounts of PC added, the sorption capacity increased while the HI did not change much. The distribution of phosphorus forms showed that CaP (ACa-P plus DAP) constituted the highest fraction in the sediment samples. Throughout the sorption process, CaP and OP changed very little, but the Ex-P and FeP increased obviously, and the presence of PC made this increase more significantly. The high specific area and the presence of iron and aluminum, as well as the modification of the sediments surface properties, make the addition of PC be favorable for the sorption of phosphorus onto sediments.