Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a group of priority pollutants that are persistent, ubiquitous, and toxic, which are released to the environment through natural and anthropogenic sources. The effectiveness of bentonite clay modified with hexadecyl pyridinium bromide has been explored for the removal of five PAHs, fluorene, phenanthrene, anthracene, fluoranthene and benzo[k]fluoranthene from spiked aqueous solutions and synthetic petroleum refinery wastewater. The studies were carried out using batch and fixed-bed column adsorption methods. The effects of various experimental parameters such as pH, mass of sorbent, contact
time and temperature on adsorption were evaluated in a series of batch experiments. The selected working parameters were then used in the fixed-bed column experiment. The removal efficiency of the adsorbent in the batch method ranged from (84 to 97 %) while for the fixedbed column adsorption it ranged from (93 to 99%). Removal of the PAHs from the synthetic petroleum refinery wastewater was higher (91 to 99%) than that from
spiked aqueous solutions (84 to 97 %). The adsorption affinities were related to the hydrophobicity of the PAHs as
determined by their log Know values which were in the order; benzo[k]fluoranthene > fluoranthene > anthracene > phenanthrene > fluorene.