Removal of polycyclic aromatic hydrocarbons from runoff by natural fibers

Abstract

Polycyclic aromatic hydrocarbons (PAHs) in runoff are of concern because they are generally toxic to aquatic organisms and many of them are carcinogenic to human. One of the alternatives for treating PAHs in runoff is to use sorption process, which can be engineered through catch basin inserts. This study investigated the application of two natural sorbents, cattail and kapok fibers, and a commercial sorbent, polyester fiber, for PAH removal from the runoff. Naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene and fluoranthene were the PAHs studied. The PAH sorption and desorption of cattail, kapok, and polyester fibers were determined using laboratory scale batch reactors and a continuous flow column under non-competitive and competitive conditions. Results showed that cattail, kapok, and polyester fibers efficiently removed PAHs from the aqueous solutions. For the batch test, the sorption data could be described well by theFreundlich isotherm. Cattail fiber exhibited the highest sorption capacity and the removal tended to increase with increasing hydrophobicity of the PAHs. Kapok fiber had the lowest PAH retention capability while cattail fiber had slightly less PAH retention capability than polyester fiber. There was a weak degree of competitive sorption between PAHs in bi-solute systems in the competitive sorption test. For the column test, based on the shape of the breakthrough curves, most compounds exhibited similar sorption and desorption characteristics. Cattail and polyester fibers showed higher sorption capacities than kapok fiber for most PAHs. Cattail fiber can potentially be used as an effective catch basin insert sorbent for removing PAHs from runoff