Combining Ultrasound With Surfactant To Remediate Diesel Oil Contaminated Soil

With the work of “Action plan for soil environmental protection and pollution control” was advanced constantly, the remediation of contaminated soil has caused widespread concern. In all monitoring points, the excessive points of oil extraction areas accounted for 23.6%, which is announced in “National survey of soil pollution” by the Ministry of land and Resources. Soil polluted by oil has been a widespread environment problem. More and more attention has been paid for developing technologies to clean up the contamination soil.Because of the advantages of the technologies of ultrasonic and surfactant washing, they have been proved to be an effective method to remediate diesel oil contaminated soil. Combined ultrasonic and surfactant washing can not only overcome the shortcomings of using a technology alone, but also can improve the effect of remediation for the contaminated soil. Therefore, combining ultrasound with surfactant to remediate diesel oil contaminated soil was studied in this paper.In this study, APG1214 and OP-10 were selected to mix with LAS respectively combine with ultrasonic to remediation of the soil contaminated by diesel oil. And the conclusions are showed as following:(1) The cleanup effect of combining ultrasound with three kinds of single surfactant respectively for diesel oil contaminated soil was obvious, and the optimum conditions are: surfactant concentration of LAS and APG1214 was 4g/l, while the concentration of OP-10 was 2g/l, water-soil ratio was 20:1, ultrasound power was500 W, ultrasound 15 min at 25℃. When the concentration of diesel oil is within a certain range, the removal rate of sand soil is higher than silty loam soil. And with the concentration of diesel oil in soil increasing, the removal rate of diesel oil showed an increasing trend.(2) The cleanup effect of combining ultrasound with mixed surfactants for dieseloil contaminated soil was obvious, and the optimum conditions were: optimum mixing ratio of two kinds of surfactants was 1:1, surfactant concentration of APG1214 mixed with LAS was 4g/l and OP-10 mixed with LAS was 5g/l, water-soil ratio of two kinds of surfactants was 20:1, ultrasound power of both was 500 W, ultrasound15 min at 25 ℃. In this part of experiment, the type of soil had little effect on the removal rate.(3)When combining ultrasound with three kinds of single surfactant respectively for diesel oil contaminated soil, the highest removal rate was got by using APG1214 as the leaching reagent. Meanwhile, if used APG1214 mixed with LAS as the leaching reagent, the removal efficiency of diesel oil is higher. As an environmentally friendly surfactant, APG1214 could get higher removal efficiency, it could be selected as preferred surfactant for the repair of the contaminated soil by diesel oil.(4)The results of column experiments can be concluded that: For the four kinds of factors, the primary and secondary effects on the removal rate is: eluent flow rate >the amount of the eluent > the type of surfactant > Ultrasonic time. The optimum conditions were: surfactant was APG1214+LAS, eluent flow rate was 25mL/min,ultrasonic time was 20s/5s and the amount of the eluent was 5L. For the upper, middle and lower sampling port, the highest removal rate was got at the upper sampling port,and the least removal rate was got at the middle sampling port.In summary, combining ultrasound with surfactant to remediate diesel oil contaminated soil was feasible and effective.