Adsorption Characteristics Of Typical Petroleum Hydrocarbons On The Aquifer Media

With the rapid development of the global economy, the petroleum industry plays vital roles in many countries and regions. While the petroleum leakage exists in the every link from the oil drilling and the transportation to the storage in the process of petroleum exploitation. The oil and gas exploration of long time leads to the ground oil around the well sites and along the pipelines with the flaky or point-like distribution, which causes the serious contamination to the groundwater and soils, and brings great risks to the ecological environment and the human health, and huge economic losses. According to all the above, it seems to be necessary to carry out the research on the transportation and migration of the petroleum contamination in the underground environment. And the adsorption is one of the key processes of the petroleum contamination during its migration. Therefore, the paper studies on the adsorption characteristics of the typical petroleum hydrocarbons on the aquifers and the factors with impaction on the process, on the aim of providing theoretic accordance to the remediation of the polluted groundwater and soil in the contamination field.In this study, the self-made rotation device was utilized to carry out the experiments for the adsorption thermodynamics and kinetic laws of the typical petroleum components-benzene, and phenanthrene on the four typical aquifer medium-silt, medium sand, coarse sand, and gravel sand, and the effect of the temperature, pH and salinity on the adsorption of naphthalene.The results of the adsorption kinetic research show that the adsorption of benzene and phenanthrene on the four aquifer media (silt, medium sand, coarse sand and gravel sand) follows the quasi secondary kinetic equation, in both of the single component solution and the mixed components solution. And the adsorption rate of benzene and phenanthrene on the four aquifer medium is in the order of silt> medium sand> coarse sand> gravel sand, both in the single component solution and the mixed components solution. The adsorption of benzene and phenanthrene on the silt is the slowest while the fastest on the gravel sand. As a general rule, the larger the superficial area of the solid-phase media is, the more the absorbance of the pollutants are. In the mixed components solution the adsorption rate of benzene and phenanthrene is faster than in single component solution. The reason may be that in the mixed components solution, other organic pollutants are adsorbed on the solid phase media, which makes the TOC of the sand increase, so benzene and phenanthrene are more easily adsorbed on the solid phase media, while the adsorption rate is increasing.The result of the adsorption thermodynamic experiments show that the Henry linear adsorption model can be used to describe the adsorption of benzene and phenanthrene on the four aquifers media (silt, medium sand, coarse sand and gravel sand) in the contaminated site both in the single-component solution and the mixed component solution. Furthermore, the adsorption capacity order of benzene and phenanthrene on the four aquifer media is silt> medium sand> coarse sand> gravel sand both in the single component solution and the mixed components solution, the adsorption capacity of benzene and phenanthrene on silt is the largest, while smallest in the gravel sand, which may be due to the Henry linear adsorption model can be used to describe the adsorption, that means the essence of the adsorption is distribution adsorption. So if the solid-phase media has higher organic matter, the pollutants will be more prone to be absorbed. This result with the specific surface area of the four solid media and the content of the TOC are the same. Moreover, on the comparison with the single-component solution, the adsorption capacity of benzene increases,while the adsorption capacity of phenanthrene decreases in the mixed components solution with the coexistence of naphthalene. The reason may be that in the mixed components solution, the solubility of benzene in water is greater than other organic components, so it can not easily be adsorbed on the solid phase media. But when other organic components are absorbed on the solid phase in the mixed components solution, it caused the TOC increased. So the adsorption of benzene also increased. Compared to other organic components, phenanthrene is most easily adsorbed on the solid phase media, but the adsorption sites of the solid phase media are limited, when phenanthrene is together with other organic components, the competitive adsorption will happen in the solid surface, making the available adsorption sites reduces, resulting the adsorbance of the phenanthrene decreases.In the experiment of coarse sand adsorbed naphthalene, the absorbance of naphthalene decreases with the increasing of the temperature, increases with the decrease of the pH, increases with the increasing of the salinity.