Removal of phenanthrene from saltwater solutions using activated carbon

Activated carbon (AC) is used for the removal of organic compounds from freshwater and saltwater systems. The effect of salinity on the sorption of organic compounds by sorbents with pores such as AC is not yet well understood. Phenanthrene sorption equilibrium and kinetic experiments are performed in the present work. An EPA granular AC bed model is employed to demonstrate the effect the salinity has on the breakthrough curves at different phenanthrene initial concentrations. At high relative to the solubility phenanthrene concentrations (200– 50 µg/L), sorption is higher in the saltwater than in the freshwater solutions. At low relative to the solubility phenanthrene concentrations (3 µg/L), sorption is lower in the saltwater than in the freshwater solutions. Activated carbon is less efficient in removing phenanthrene from saltwater than from freshwater solutions when phenanthrene is present at low relative concentrations (<10 µg/L).

The most important conclusions of this work, utilizing activated carbon for the removal of phenanthrene from a water solution, are as follows: • At high relative to the solubility phenanthrene concentrations (200–50 µg/L), SW increases sorption. • At low relative to the solubility phenanthrene concentrations (3–10 µg/L), sorption decreases and the sorption uptake is lower in SW than in FW. • Results obtained from modeling phenanthrene flow through a granular AC bed agree well with the sorption kinetics results. Activated carbon is less efficient in removing phenanthrene from SW than from FW solutions when phenanthrene is present at low relative concentrations (<10 µg/L).