The effect of a chelator mediated fenton system on activation of TMP fibres and decolorization of synthesized dyes

IRG/WP 04-50223

Yuhui Qian, B Goodell, J Jellison

The purpose of this work is to improve our current knowledge of the non-enzymatic mechanisms involved in the brown rot degradation of wood, but also to study the potential applications of a chelator-mediated Fenton system in activation of wood fibers and decolorization of synthesized dyes. In this work, Electron Spin Resonance (ESR) spin-trapping techniques were used to study the generation of hydroxyl radicals in a mediated Fenton system. The activation of Thermal Mechanical Pulp (TMP) fibers was also evaluated by ESR measurement of free phenoxy radical generation on solid fibers. The results indicate that low molecular weight chelators can improve Fenton reactions, thus in turn stimulating the free radical activation of TMP fibers. However, the data also show that excessive and prolonged free radical treatment may cause the destruction of fiber phenoxy radicals. A mediated Fenton system was evaluated for decolorization of several types of synthesized dyes as well. The results show that, compared to a neat Fenton process, the mediated Fenton process increased the production of .OH species to increase the decolorization efficiency. The color of a dilute liquid dyes (Carta Yellow RW, Carta Yellow G, or Cartasol Red 2GF) was effectively reduced to a colorless level after 90 minutes of treatment at room temperature by a mediated Fenton process. In conclusion, this study demonstrates the potential for application, but also the complexity of free radical chemistry in biological materials, especially with regard to the chelation of transition metals and the interaction between free radicals. The complexity of the dyes is similar to that of some organic wood preservatives and may provide a means for remediation of preservative contaminants in soils.

Keywords: Brown rot; hydroxyl radical; Electron Spin Resonance; wood fibers; phenoxy radical; dyes; waste water treatment

Conference: 04-06-06/10 Ljubljana, Slovenia

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