Surfactant Screening Of PCB138 In Contaminated Soil And Study On Degradation Of Contaminants In Eluent

As a persistent organic pollutant,PCBs are widely distributed all over the world due to their environmental persistence,bioaccumulation,high toxicity,semi-volatility and long-distance mobility,causing serious pollution to the environment.In this paper,black soil is selected as the test soil,six different surfactants of four types: anionic,cationic,nonionic and amphotericfour are selected,and the elution of PCB138 in the soil by single and composite surfactants is analyzed,and the unactivated potassium persulfate system and copper oxide and copper sulfate/EDTA are also selected.Two activated potassium persulfate systems were used to study the degradation of PCB138 in the eluent,and the factors affecting its degradation were analyzed.The elution experiment results show that: among the single surfactants,the nonionic surfactants APG06 and Tween80 and the anionic surfactants SDS and SDBS have better elution effects,of which APG06 has the best elution effect and the highest elution rate is 42.2%.Followed by SDS,Tween80 and SDBS,the highest elution rates were 34.8%,27.9% and 17.4%;cationic surfactant 1227 and amphoteric surfactant CAB-35 followed,the highest elution efficiency were 10.9% and 6.9%,respectively.The elution effect of the compound surfactant on the PCB138 in the soil is better than that of the single surfactant in the experiment.The SDS-APG06 negative-non-complex surfactant has the best elution effect,and the optimal concentration ratio is:SDS 7500mg/L,APG06 7000 mg/L,the elution rate is 58.3%.The degradation experiment results of potassium persulfate system showed that within 0-10 min,the degradation rate of PCB138 in the eluent increased rapidly with potassium persulfate,and the growth rate of degradation rate gradually slowed down after 10 min.Copper oxide activated potassium persulfate system and copper sulfate/EDTA activated potassium persulfate system degraded PCB138 better than unactivated potassium persulfate.As the dosage of potassium persulfate and activated substance increases,the degradation rate tends to increase first and then decrease.The degradation rate of PCB138 decreases with the increase of the initial concentration of pollutants,and the optimal pH value in the experiment is 7.