[Chemical oxidants for remediation of BTEX-contaminated soils at coking sites].

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.