Research Of Remediating PAHs-contaminated Soil By EK Combined With Laccase

The persistent pollution in the environment and potential threats on human health from the polycyclic aromatic hydrocarbons(PAHs)contaminated sites have attracted more and more people's attention.This could be mitigated by the technology of Electrokinetics(EK)combine with laccase,which as a new soil remediation technology.In this paper anthracene were chosen as typical pollutant,it had studied the feasibility of laccase to degrade anthracene contaminated soil,the migration efficiency of anthracene by EK technology,the migration and transformation efficiency of pollutant by the hyphenated techniques of EK and laccase.The main research conclusions are as follows:1.It is feasible for laccase to degrade anthracene contaminated soil,and the degradation rate is higher by laccase-ABTS system.In addition,laccase catalytic reaction conform to the Michaelis-Menten kinetics.2.The anolyte enhanced EK remediation technology could maintain soil pH to a certain extent and prevent acidification phenomenon.When selecting 0.1mol/L NaAc/HAc as anode/cathode buffer,the voltage gradient of 1V/cm,could obtain the higher values of electric current,electrosmotic flow,electrical conductivity;and cause the soil moisture content change smaller.However,there was no significant migration of the pollutant in soil due to the anthracene's hydrophobicity.3.Because of using the hyphenated techniques of EK and laccase,anthracene could be migrated to the ends of the soil,the mobility respectively 24.1%,30.4%,but conversion is not obvious.By adding mediator ABTS,anthracene could obtain migration and transformation simultaneously,from the anode to the cathode,the degradation rate showed an increasing trend,the highest degradation rate was 40.9%,which proved EK/laccase(ABTS)system more conducive to the migration and transformation of pollutant in contaminated soil.The properties of soil(moisture content)and electric field had little influence in the migration and transformation of anthracene.By adding surfactants Tween80 and SDS,could improve the remediationefficiency by EK/laccase(ABTS)system,and when adding Tween80 and ABTS together could achieve the maximum values,with an average degradation rate of25.3%.