Studies on the sorption behaviors of phenanthrene on marine sediments.

In the present study, the sorption behaviors of phenanthrene on marine sediments were investigated. Through the study of the adsorption kinetics and isotherms, the adsorption mechanism of phenanthrene on marine sediments was described. The results showed that the adsorption kinetics of phenanthrene on marine sediments could be described by the second-order kinetic equation. The sorption rate of phenanthrene was very rapid, and the equilibrium time was slightly longer in deionized water than in natural seawater. The adsorption isotherms of phenanthrene on all the sediments could be very well described by Freundlich equations. The adsorption capacity of phenanthrene had a significant positive correlation with the sediment organic carbon content. Some external factors that could affect adsorption behaviors of phenanthrene were also investigated. Results of the present study showed that the adsorption capacity of phenanthrene on the sediment decreased with increasing temperature. Moreover, the adsorption amounts of phenanthrene on the sediment appeared to be lower in natural seawater than in deionized water. Finally, the presence of the surfactant of Tween20 in the system could enhance the adsorption of phenanthrene on the sediment, and the adsorbance was proportional to the concentration of Tween20.