Influence of peat on Fenton oxidation

Abstract A diagnostic probe was used to estimate the activity of Fenton-derived hydroxyl radicals (·OH), reaction kinetics, and oxidation efficiency in batch suspensions comprised of silica sand, crushed goethite ( α -FeOOH) ore, peat, and H 2 O 2 (0.13 mM). A simple method of kinetic analysis is presented and used to estimate the rate of ·OH production ( P OH ) and scavenging term ( k S ), which were used to establish the influence of organic matter (Pahokee peat) in Fenton systems. P OH was greater in the peat-amended systems than in the unamended control, and k S was approximately the same. Any increase in scavenging of ·OH that resulted from the addition of peat was insignificant in comparison to radical scavenging by reaction with H 2 O 2 . Also, treatment efficiency, defined as the ratio of probe conversion to H 2 O 2 consumption over the same period was greater in the peat-amended system. Results suggest that ·OH production is enhanced in the presence of peat by one or more peat-dependent mechanisms. Fe concentration and availability in the peat, reduction of Fe(III) to Fe(II) by the organic matter, and reduction of organic-complexed Fe(III) to Fe(II) are discussed in the context of the Fenton mechanism.