Enhancing Plant-microbe Associated Remediation Of PAHs Contaminated Soil By Anionic-nonionic Mixed Surfactants

Anionic-nonionic surfactants can synergistically solubilize organic pollutants, and enhance the phenanthrene microdegradation in soil-water systems under certain conditions, or promote plant uptake of PAHs from aqueous solution. Up to date, little information is available on the plant-microbe associated bioremediation of polycyclic aromatic hydrocarbons (PAHs) in the presence of anionic-nonionic mixed surfactants. Thus, the enhancing plant-microbe associated bioremediation of phenanthrene and pyrene contaminated soil by anionic-nonionic mixed surfactants were introduced and tested in this study in order to supply valuable information for high-efficiency, low-cost soil bioremediation technologies. And the main results of this thesis are shown as follows:(1) Mixed surfactants with SDBS-Tween80can synergistically reduce interfacial tension of soil solution, and enhance the elution of PAHs in contaminated soils.600mg/L mass ratio of2:3mixed surfactants with SDBS-Tween80make the interfacial tension of purple soil solution reduce by51.1%than that without surfactant control, and the same concentration of Tween80fell by only6.3%;5000mg/L mass ratio of2:3mixed surfactants with SDBS-Tween80enhanced by18.1times and76.3times of elution efficiency of phenanthrene and pyrene in purple soil than that of control, and1.79times and1.45times than that of single Tween80, respectively.(2) A certain ratio and concentration of SDBS-Tween80mixed surfactants synergistically enhanced plant-microbe associated bioremediation of PAHs contaminated soil, and were more effective in promoting plant-microbe associated bioremediation than the same amount of single surfactants. Only about1/15-1/8of mixed surfactants was needed to remove the same amount of phenanthrene and pyrene from the planted soil, compared to Tween80. When100mg/kg of anionic-nonionic mixed surfactants were added to the soil, the soil bacterial community did not changed significantly, and to some extent, this experimental concentration did not exist ecological risk.