| In order to accurately assess the migration of ethanol gasoline components in the environment and their environmental risks, batch experiments were carried out to investigate the sorption of toluene on humic acid with the presence of various content of ethanol. The results showed that as the volume fraction of ethanol increased, the solubility of toluene in system increased linearly. The sorption process could be divided into two stages, i.e., fast sorption in the beginning and then slow sorption to the equilibrium. The sorption procedure of toluene on humic acid can be well described by the Freundlich model. The influence of presence of ethanol on sorption of toluene on humic acid was significant. Under the conditions of pH=5.9±0.2 and （25±1）℃, when ethanol fraction（in volume） increased from 0 to 20%, the sorption affinity（K） of toluene by humic acid decreased from （0.143±0.021） to （0.066±0.012）mgn+1·L-n·g-1, and the Freundlich constant（1/n） tended to be unity. This situation showed that ethanol could not only reduce sorption amount of toluene on humic acid, but also enhance the sorption homogeneity with increase in isotherm linearity. The fitted cosolvency power of ethanol was 3.45 from sorption data and it was less than that from solubility data, which was 3.87, under current experimental condition. This indicated that humic acid maybe swelled under the effect of ethanol. |
