Treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans contaminated soil using S2O82- with ferrous ion and heat as activating methods

Abstract

The uses of Fe2+ and thermal energy as S2O82- activating methods for the treatment of polychlorinated dibenzop-dioxins and dibenzofurans (PCDD/Fs) contaminated soil using S2O82- were simultaneously studied for the first time. PCDD/Fs degradation was conducted using S2O82- with and without the Fe(2+ )addition M 25 degrees C, 40 degrees C, and 60 degrees C, and the process of S2O82- without Fe(2+ )showed the best performance, 99.0% removal efficiency of 17 PCDD/Fs in 72 h. The SO4 center dot- based process is effective for the degradation of PCDD/Fs. The presence of Fe(2+ )greatly influenced the soil pH development during the process, but the pH change showed an insignificant effect on PCDD/Fs degradation by the SO4 center dot- based process. The performances of several options implied that the direct interactions of Fe2+, heat, and S2O82- on PCDD/Fs are very few, and interestingly, the combination of Fe2+ and thermal energy did not always show a clear advantage over the individual use of Fe2+ or thermal energy. The behaviours of PCDD/Fs in S2O82- based process is consistent regardless of an activating method. The lower-chlorinated PCDD/Fs were easier to be degraded than higher ones, and in most cases, more PCDFs were degraded than PCDDs in the case of same chlorine numbers.