Study On Magnetic Force-enhanced Electrokinetic Remediation Of Triclosan-contaminated Soil

In recent years,soil pollution has become a serious problem,and thus soil remediation has become a promising research area in the field of environmental protection.Personal care products and drugs have gradually become new kinds of soil pollutants.Because of the low concentration of these pollutants in the initial field of use and small acute toxicity,these products are not much concerned.Triclosan is a broad-spectrum antimicrobial agent,which has widely been used in a series of personal and household products,such as soaps,textiles,toys and coatings.At present,triclosan has been listed as one of the 10 major organic pollutants in the environment.Although triclosan does not have much acute toxicity,it is hard to degrade in environment.Some researches point out that triclosan can disturb human endocrine and affect gene expression and that triclosan is a new kind of pollutant.Now soil remediation technology has been developed constantly.Conventional technologies including physical remediation,chemical remediation and bioremediation have been promoted by being combined with one or more other remediation technologies to remediate contaminated soil.Magnetic force-enhanced electrokinetic remediation technology was developed to remediate triclosan contaminated soil,which had high efficiency,low cost,no pollution and a good prospect.In this study,a new trial model was designed.triclosan-contaminated soil was treated by magnetic force-enhanced electrokinetic remediation(MFE-EK),and the main achievements were as follow:⑴ First,a method for recovery and detection of triclosan and performance of sorption kinetics and sorption-desorption research.Results indicated that ultrasonic extraction of triclosan was performed using 50 mL methanol,92.17%~96.45% triclosan was recovered.The detection wavelength was 281 nm.Adsorption equilibrium time was less than 1000 min,and that the sorption of triclosan on soil was irreversible.⑵ More,doing research on effects of water content and electrode shape on triclosan removal efficiency.For good results,the soil water content was kept 35.0% and cylinder shaped electrodes were used.Orthogonal experiments were performed to make out the effects of voltage gradient,pollutant concentration and magnetic field strength on removal efficiency.It suggested that high voltage gradient and strong magnetic force tended to improve working efficiency of MFE-EK system.Lower concentration of triclosan,and higher removal efficiency was obtained.50.7% triclosan was removed from anode section when its original concentration was 1,000mg/kg,with 3v/cm voltage gradient and 80 mT magnetic field strength.⑶ Last,analysis of the effects of MFE-EK process on soil properties,including soil pH,water content,conductivity and temperature.Soil temperature was recorded every 10 hours,and the others were detected when the experiments were ended.Because of water electrolysis,soil pH increased in cathode section and decreased in anode section.With periodic addition of electrolyte,soil temperature was relatively stable in soil chamber and change periodically in electrode chambers.The water content value increased from anode to cathode section.Soil conductivity was low in middle section and high in anode and cathode section.