Experimental Study On Remediation Of Nitrobenzene Contaminated Soil By Surfactant Leaching

Surfactant leaching method is fast and low cost.It reduces the soil interfacial tension,increases the solubility of nitrobenzene,promotes the migration of nitrobenzene with the eluent,thus increases the leaching efficiency.So it is widely used to repair nitrobenzene contaminated soil.This article is targeted to specific pollution intensity of nitrobenzene contaminated soil.The solubilization and desorption of nitrobenzene with an anionic surfactant SDS,an anionic surfactant SDBS,a nonionic surfactant Tween-80,a nonionic surfactant Triton X-100 were studied emphatically.By contrast,the best surfactant was determined and subjected to column experiments.The effects of surfactant concentration and flow rate on the leaching experiment were analyzed and studied.The experimental basis was provided for the practical application of surfactant leaching method to repair nitrobenzene contaminated soil.According to the experiment and data,the following conclusions are obtained:(1)The order of solubilization ability of four kinds of surfactants to nitrobenzene was: Tween80>Triton X-100>SDBS>SDS.The solubilization capacity of the two nonionic surfactants is greater than that of the two anionic surfactants.The desorption capacity of the four surfactants to nitrobenzene is: SDBS>SDS>Tween80> Triton X-100.The desorption capacity of the two anionic surfactants is greater than that of the two nonionic surfactants.(2)Through the water and surfactant SDBS,SDS leaching to repair nitrobenzene contaminated soil column experiment can be concluded:The best flow rate of using water to leach contaminated soil column is 1m L/min,the highest removal rate of nitrobenzene was 82.8%.The best concentration of using SDBS to leach contaminated soil column is 1000mg/L,the best flow rate of 2m L/min,the highest removal rate of nitrobenzene was 80.3%.The best concentration of using SDS to leach contaminated soil column is 2000mg/L,the best flow rate of 1m L/min,the highest removal rate of nitrobenzene was 74.4%.The order of the effects of the three eluents was: water>SDBS>SDS.(3)During the rinsing process,the surfactant is heavily adsorbed on the soil,resulting in a reduced concentration of the eluent,affect the effect of its solubilization.In addition,with the progress of the leaching process,the surfactant adsorbed on the soil not only can not play a role in solubilization,but adsorb the leached nitrobenzene,and thus,the removal rate of nitrobenzene decreased.The effect of water leaching is greater than that of surfactant SDBS,SDS.(4)For nitrobenzene such a certain water-soluble organic pollutants,do not need to add surfactants,water leaching can get a better removal effect.After the leaching of soil to achieve the "Standard of Soil Quality Assessment for Exhibition Sites HJ350-2007" B standard 100mg/kg.