Sorption Of Organic Pollutants On Soil, Soil Contaminated With Crude Oil And Soil Mixed With Sludge From Water

Organic pollutants have been of grate concern due to their persistence in the environment, their bioaccumulation potential in the tissues of animal and humans through the food chain, and their toxic properties for human and wildlife. The behavior of adsorption/desorption of organic pollutants on soil becomes particularly important in risk assessment, controlling pollution and developing remediation strategies.In this paper, some experiments were conducted on the basis of Xinjiang soil's characteristics as following:1.Three typical organic contaminant, low-molecular-weight polar nonionic compounds (presented by 2, 4-dinitrotoluene in this paper), nonpolar nonionic compounds (presented by phenanthrene) and relative polar organic compound p-nitrophenol, were selected to measure sorption isotherms on soils with low organic matter collected from Xinjiang from water. The contributions of organic matter and mineral were calculated for illuminating the mechanisms of sorption. The influence of temperature and ionic strength of solution on sorption were discussed. Results indicated that sorption of the compounds fitted well to the conventional linear model, ionic strength for adsorption of organic pollutants had no significant effect on sorption coefficient, and however, there were appearance effect on sorption coefficient at different temperature.2.The sorption of 2, 4-dinitrotoluene and 1, 3-dinitrobenzene on soils collected from crude-oil exploration area in Xinjiang was investigated to study the influence of crude oil on sorption mechanisms. Results indicated that the sorption coefficients of 2, 4-dinitrotoluene on soils contaminated with low concentration crude oil were lower than those on uncontaminated soils, sorption mechanisms included partition of soil organic matter and adsorption of minerals in soil. However, the sorption coefficients of 2, 4-dinitrotoluene on soils contaminated with high concentration crude oil were higher than that on uncontaminated soil, and the increase values of sorption coefficients were positive correlated to the crude oil concentrations in soils. The sorption coefficients of 1, 3-dinitrobenzene on soils contaminated with low concentration crude oil were lower than those on uncontaminated soils. However, the sorption coefficients of 1, 3-dinitrobenzene on soils contaminated with high concentration crude oil were much higher than that on uncontaminated soil, and the increase values of sorption coefficients were also positive correlated to the crude oil concentrations in soils. The translocation of 2, 4-dinitrotoluene and 1, 3-dinitrobenzene was decreased by high crude oil concentration in soils. The sorption mechanism was gradually dominated by partition of 2, 4-dinitrotoluene and 1, 3-dinitrobenzene into crude oil phase in soil。3.There are many nutrient components in sludge, such as organic compounds, K, N and P, result in high value in agriculture use. However, contaminants in sludge restrain their use. Sludge collected from Urumqi Hedong sewage treatment plant were mixed with three different types of soil in different ratios, after two years aging period, the soils mixed with sludge were used as adsorbent to study the influence of sludge on the environment behavior of organic contaminant (p-nitrophenol) in soils. Results showed that the p-nitrophenol sorption isotherms from water on soils mixed with sludge are consistent with Freundlich isotherm, the adsorption distribution coefficient increased significantly with the increase of sludge concentration in soil. The addition of sludge decreased the transport ability of p-nitrophenol in soil.