Colloids-facilitated Transport Of Phenanthrene In Petroleum-contaminated Site

Soil sample was collected from Liaohe petroleum contaminated field in northeast China. Three particle size (5?2?m?2?1 ?m and<1?m) colloids were extracted by using the siphon methods. Distribution of particle size, Zeta potential and micro-morphology of the colloids were detected. Leaching experiments were conducted with the three particle size of colloid in porous media of quartz sand to investigate the effect of environmental factors (pH, ionic strengths of the bulk solution) on the transportation of soil colloid in saturated porous media. The mass fraction of colloid recovered (MR) was used to describe the characterization of colloid transportation in porous media. Results indicated that the percentage of the colloid in each size were 75%?76% and 72%; Colloids isolated from the petroleum contaminated soil presented scaly; Zeta potential was in the range of-32.4?-40.4 mV?-35.0?-49.8 mV and -24.0?-52.4 mV as pH changed from 4 to 9. MR of the three sizes colloids were 31.62%-63.39%,58.55%-81.25%,62.27%-83.51% respectively when pH of the bulk solution varied from 4 to 9. This indicated that pH had a significant impact on colloid transport, and that colloid more easily transported through the porous medium in neutral solution condition. MR decreased as the ionic strength of the bulk solution increased from 0.001 mmol/L to 1 mmol/L. This suggested that inorganic ion reduced migration. Meanwhile, the colloid with small size transported through the porous medium more easily.Phenanthrene contaminated surface soil leaching simulation experiments show, Eluent added colloid change phenanthrene migration in sand column. Phenanthrene was adsorbed on the colloid, and migrated with the migration of colloids. But with decreasing particle size, the colloid of petroleum contaminated sites facilitated transport capacity declined due to TPHs reduced. With pH from 4 to 8, colloid of 5?2 ?m migration capacity enhancement, facilitation of transport in phenanthrene capacity enhancement. With the increase of ionic strength, the ability to decrease the migration of colloid, phenanthrene is also fixed to the porous medium.