Continuous upflow bench-scale column experiments were carried out to investigate the use of a synthetic form polymer, polypropylene, and polypropylene coated with a thin layer of n-hexane as sorbents for hydrophobic organic compounds present in the effluent of municipal wastewater treatment plant. Two polycyclic aromatic hydrocarbons, namely, phenanthrene and fluorene, were selected as representative hydrophobic organic compounds for experimental purposes. The effect of flow rate, column diameter and column height on the removal efficiency of polycyclic aromatic hydrocarbons was investigated. Removal efficiency was found to correlate well with hydraulic retention time, showing that retention time is the primary parameter in the design of the adsorption column. Dissolved organic matter did not sorb onto polypropylene or polypropylene coated n-hexane, and the presence of dissolved organic matter in the aqueous phase did not significantly affect sorption of polycyclic aromatic hydrocarbons. For experiments with polypropylene coated with n-hexane, an insignificant amount of n-hexane (less than 0.03 times the aqueous solubility of n-hexane in water) was lost due to dissolution in the effluent. The potential use of polypropylene coated n-hexane in upflow column experiments for the removal of hydrophobic organic compounds from the effluent of municipal wastewater treatment plants was demonstrated.

The use of a synthetic form polymer, polypropylene, as a sorbent for hydrophobic organic compounds present in municipal wastewater treatment plant effluent was investigated. To enhance the sorption capacity of polypropylene for hydrophobic organic compounds, polypropylene was coated with a thin layer of n-hexane. Sorption of target compounds onto polypropylene and polypropylene coated with n-hexane was evaluated by carrying out equilibrium and kinetic batch experiments. Three polycyclic aromatic hydrocarbons, namely, phenanthrene, fluorene and naphthalene, were selected as representative hydrophobic organic compounds for experimental purposes. The effect of pH, ionic strength and dissolved organic matter on sorption was investigated. The results showed that polypropylene coated with n-hexane performed better than polypropylene as a sorbent for polycyclic aromatic hydrocarbons, in terms of sorption capacity and sorption kinetics. Ionic strength and pH did not have a significant effect on the sorption of polycyclic aromatic hydrocarbons. Dissolved organic matter in the form of humic acid did not sorb onto polypropylene or polypropylene coated with n-hexane, and the presence of dissolved organic matter in the aqueous phase did not significantly affect sorption of polycyclic aromatic hydrocarbons.

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