Sorption of 2,4,6-Trinitrotoluene to Natural Soils Before and After Hydrogen Peroxide Application

Abstract

Laboratory batch sorption experiments were conducted to investigate the impact of hydrogen peroxide (H2O2) pre-application on post-sorptive behavior of 2,4,6-trinitrotoluene (TNT) in different natural soils (average soil, high Fe soil, and high pH soil). After H2O2 application, the values of Freundlich coefficient Kf were increased by ∼ 160% for the average and high pH soils and by ∼ 120% for the high Fe soil, showing that the soils became more favorable for TNT sorption after H2O2 application. Nonlinearity in terms of the Freundlich exponent n was increased by ∼ 40% for the average and high pH soils and by ∼ 30% for the high Fe soil, showing greater sorption affinity of TNT for the oxidized soils at lower TNT concentrations and also implying greater TNT availability for transport at high concentrations. The increase in sorption extent for the H2O2-oxidized soils was presumably attributed to the oxygen-induced enhancement in the sorption capacity of the soils and the more dominant contribution of clay minerals to sorption. Therefore, enhanced sorption following H2O2 application may inhibit the subsequent formation of a TNT plume after either source zone remediation or plume remediation using H2O2 such as Fenton oxidation.