Sorption of polycyclic aromatic hydrocarbons from aqueous solution by hexadecyltrimethylammonium bromide modified fibric peat

BACKGROUND: Fibric peat was modified by hexadecyltrimethylammonium bromide (HTAB) to improve its performance in sorption of polycyclic aromatic hydrocarbons (PAHs). The raw fibric peat (P-R) and surfactant modified peat (P-HTAB) were characterized by capillary rise test to determine the effect of HTAB on surface hydrophobicity. Effect of contact time was also investigated. Batch sorption data were fitted to the Freundlich model and pseudo-second-order model for isotherm and kinetics study. RESULTS: P-HTAB had a more hydrophobic surface than P-R. After modification, the sorption coefficients (K-OC) of naphthalene, phenanthrene and pyrene on fibric peat increased from 1590, 29661 and 204171 mL g(-1) to 2006, 52410 and 358569 mL g(-1), respectively; the sorption rate constants of naphthalene, phenanthrene and pyrene increased from 0.00057, 0.00036 and 0.00051 g mu g(-1) min(-1) to 0.00062, 0.00140 and 0.00155 g mu g(-1) min(-1), respectively. The sorption coefficients of PAHs were positively correlated with the octane-water partition coefficients of PAHs. CONCLUSIONS: The hydrophobicity of fibric peat was enhanced through modification by HTAB, which resulted in the improved sorption rate and sorption capacity for PAHs. The sorption performance of P-HTAB reveals that it is an effective biosorbent for PAHs and has potential for treatment of wastewater containing hydrophobic organic contaminants. (C) 2010 Society of Chemical Industry