Removal of polycyclic aromatic hydrocarbons (PAHs) from petrochemical wastewater was investigated using various low-cost adsorbents of natural origin including sugar cane bagasse, green coconut shells, chitin, and chitosan. Adsorption experiments of mixtures of PAHs (5.0-15.0 mg/L) have been carried out at ambient temperature (28 +/- 2 degrees C) and pH 7.5. The adsorption isotherms of PAHs were in agreement with a Freundlich model, while the uptake capacity of PAHs followed the order: green coconut shells > sugar cane bagasse > chitin > chitosan. The adsorption properties of green coconut shells were comparable to those of some conventional adsorbents such as Amberlite T. The partition coefficients in acetone:water, the adsorption constants at equilibrium, and the molecular masses of the PAHs could be linearly correlated with octanol-water partition coefficients. (c) 2007 Elsevier Ltd. All rights reserved.