[Adsorption of toluene and naphthalene on Beijing soils and its influence factor]

Static adsorption experiments were carried out to investigate the adsorption of toluene and naphthalene on Beijing soils, and to determine the influence of temperature and surfactants on adsorption. Although the affinity of petroleum hydrocarbons for seven soils is different, the adsorption isotherms of toluene and naphthalene on seven soils are well described by the Freundlich type. The adsorbed amount of naphthalene is higher than that of toluene on the same soil. High temperature doesn't benefit adsorption. Cetylrimethyl ammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS) both have a positive effect on desorption of toluene and naphtalaene from soil. The desorption rate of toluene and naphthalene in the presence of CTAB and SDBS is 27.5%, 12.1% and 64.3%, 48.8%, respectively, which show that SDBS plays a much more important role in desorption than CTAB. The adsorbed quantities of toluene and naphthalene decrease with increasing SDBS concentration. When CTAB concentration is lower than the critical micelle concentration (CMC), adsorption increases with increasing CTAB concentration; When CTAB concentration is equal to or higher than CMC, adsorption decreases with increasing CTAB concentration.