不同化学氧化剂对焦化污染场地苯系物的修复效果

Chemical Oxidants for Remediation of BTEX-contaminated Soils at Coking Sites

采用自制全封闭模拟装置比较研究了Fenton试剂、类Fenton试剂、高锰酸钾以及活化过硫酸钠4种常用的化学氧化剂对焦化工业污染场地中苯系物的去除效果.结果表明,去除土壤BTEX效果较好的是Fenton试剂和类Fenton试剂,在最佳剂量条件下分别能使BTEX的浓度降低83%和73%,且反应过程中经挥发进入到回收液中的比例较小,均低于4%,因此应用Fenton试剂和类Fenton试剂对BTEX的实际去除率分别能达到80%和71%.其中二甲苯的去除率最高,在65%以上,其次是苯和甲苯,去除率最低的是乙苯.高锰酸钾和活化过硫酸钠处理后的土壤中BTEX的浓度虽有所降低,但高达83%和77%的BTEX都通过挥发进入到了回收液中,表明它们的处理只是促进污染物的解吸和挥发,而不能有效地将污染物氧化进而从环境中去除.

An enclosed reactor was used to evaluate Fenton reagent,modified Fenton reagent,potassium permanganate and activated persulfate for removal of benzene,toluene,ethyl benzene,and xylene（BTEX） from soil at contaminated industrial coking sites.The results showed that Fenton reagent and modified Fenton reagent were the optimum oxidants for removing BTEX,and these oxidants decreased the concentration of BTEX in soils by 83 % and 73 %,respectively.The proportion of BTEX volatilized from the soil was 4% in both cases,and the rates of BTEX removal from the whole system were 80% and 71%.More than 65% of xylene was removed after treatment with Fenton reagent and modified Fenton reagent.In contrast,benzene,toluene were more resistant to oxidation,and ethyl benzene was the most resistant of these compounds.The concentration of BTEX decreased to some extent when permanganate and activated persulfate were used as oxidants.However,the proportions of volatilized BTEX were 83 % and 77 % for permanganate and activated persulfate,respectively.This indicates that they could stimulate the desorption and volatilization of BTEX,while they were ineffective for removing BTEX from the environment.