Adsorption of polycyclic aromatic hydrocarbons from synthetic wastewater by organoclays

Abstract

The effect of the amount of organic cation on the characteristics and PAHs sorption of organoclays were investigated. Dodecylpyridinium chloride (DPC), naphthalene, and phenanthrene were selected to represent organic cation and PAHs, respectively. Eight organoclays were synthesized by exchanging the inorganic cations on the clay surfaces with DPC at loading level of 0.25-2.00 times the cation exchanged capacity (CEC). Organoclays were characterized by Accelerated surface area and porosimetry system, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The adsorption of DPC noto clay and the sorption of PAHs from aqueous solution by organoclays were studied by batch experiment. The results showed that DPC could be adsorbed ontto clay in excess of the CEC of clay, The characteristics (e. g., the BET surface area, the interlayer spacing, and structural features) of organoclays and sorption capacities of PAHs noto organoclays depended on the amount of DPC applied. The sorption isotherms of PAHs onto organoclays were linear, indicated that partition was the main mechanism of PAHs sorption by organoclyas. The sorption capacities of PAHs increased with the amount of DPC increased from 0.25 to 1.25 times the CEC. When the amount of DPC increased from 1.25 to 2.00 times the CEC, the sorption capacities were not different. The distribution coefficient (K ) of naphthalene ranged from 0.151 to 1.675 L/g and phenanthrene from 0.426 to 36.184 L/g.