Experimental Study On Remediation Of Aniline Contaminated Soil By Surfactant Leaching

Soil leaching method is widely used in various contaminated soil remediation projects because of its low operating cost and good restorative effects.Four kinds of surfactants were selected at the beginning of this paper: sodium dodecyl benzene sulfonate(LAS),sorbitol monooleate(Tween80),Alkyl polyglucosamine(APG),fatty acid methyl ester sulfonate(MES).Through the solubilization experiment,two kinds of surfactants with better solubilization effect were selected for soil washing and soil leaching experiments.The relevant experimental parameters of the optimum conditions for shaking leaching,continuous leaching of soil columns and intermittent leaching of soil columns were determined:(1)Four kinds of surfactants were selected after literature reviewing,and the solubilization experiments showed that thoes four kinds of surfactants had different degrees of solubilization effect to aniline,the solubilization ability of them was: APG>Tween80>LAS>MES.The optimum temperature range for aniline solubilization is at 40~45?,and the solubilization effect of anionic surfactants is less affected by temperature changes.(2)The best conditions for shake leaching experiment of surfactant are: for water,liquid solid ratio is 30 with 1h shaking time;for LAS,liquid and solid ratio is 20 with 1.5h shaking time;for APG,liquid solid ratio is 20 with 1h shaking time.The effect of shake washing is: water>LAS>APG,in which clear water washing with maximum removal rate 93.7%.The optimum conditions for the leaching experiment of soil column are as follows: the flow rate of the best rinse solution for continuous rinsing of clean water is 1mL/min;the flow rate of the best leaching solution for continuous leaching of LAS is 0.5mL/min;the flow rate of the best leaching solution for continuous leaching of APG is 1mL/min.The order of soil column leaching effect is: water>LAS>APG.The best intermittent time for intermittent washing is 8h~12h,and the best leaching efficiency is 96.97%,which is 5.21 percentage points higher than that of continuous leaching.(3)For two kinds of soil leaching,the removal efficiency of water to aniline is higher than that of LAS and APG.By washing the soil column intermittently,the leaching conditions can be improved,and the tail effect of continuous leaching can be improved,thereby improving the removal rate of aniline in soil.(4)The interaction between surfactant and soil pollutants is an important factor affecting its effectiveness.LAS and APG have complex effects on the soil with aniline,and the increase of aniline adsorption in soil is greater than that of reduction.With the increase of the concentration of two kinds of surfactant,the total adsorption of aniline in the soil increases gradually,thus reducing the removal rate of aniline,so the two kinds of surfactants added to the experiment are not good for the removal of aniline,the washing effect of clean water is better than that of surfactant.In addition,LAS and APG can also reduce the interfacial tension at a relatively low concentration.