Kinetics study of aqueous sorption of phenanthrene to humic acids and sediments

The sorption behavior was determined for a model polycyclic aromatic hydrocarbon (PAH), i.e., phenanthrene(PHN), from water to three humic acids (HAs) and three sediments in different reacting time. The chemical compositions of HA samples were measured using cross polarization magic angle spinning carbon-13 (CPMAS 13C NMR along with elemental analysis. The dissolved humic substances dissociating from solid HAs and sediments were characterized by 'H NMR. The experiments indicated that the sorption modes and mechanisms of natural sorbents for PHN varied significantly between short (< 7 d) and long contact time and the reaction time should be taken into consideration in studying the overall sorption process. The sorption capacity (K'f) and exponent (n) might be relative to the properties of dissolved humic materials in initial stage but the solid aromatic organic matter after long time reaction. According to the experiments performed in this investigation and the previous researches, a conceptive sorption model was established.