Fenton Oxidation of Metsulfuron-Methyl with Application to Permeable Reactive Barriers

Laboratory experiments were conducted for removal of metsulfuron-methyl (MeS) by Fenton oxidation using a sand column with multiple sampling points and varied flow rates. The transport and degradation of MeS in a sand column were modeled using an advection diffusion reaction system with rate-limited sorption, hydrolysis and second-order degradation kinetics. Rate constants for MeS adsorption and degradation were obtained by fitting the model to experimental breakthrough curves. Results showed that the residence time is the primary influencing factor in the amount of MeS removal by Fenton oxidation with removal efficiencies exceeding 85 %. The column model was extended to two-dimensional porous media, and simulations were conducted to evaluate the feasibility of in situ chemical oxidation using Fenton’s reagent in permeable reactor barriers. Results show that Fenton oxidation can yield remediation efficiencies exceeding 80 % in permeable reactor barriers when compared to less than 10 % with adsorption only.