Hydroxyl radical production by a heterogeneous Fenton reaction supported in insoluble tannin from bark of Pinus radiata

摘要

Fenton reactions driven by dihydroxybenzenes (DHBs) have been used for pollutant removal via advanced oxidation processes (AOPs), but such systems have the disadvantage of DHB release into the aqueous phase. In this work, insoluble tannins from bark can be used to drive Fenton reactions and as a heterogeneous support. This avoids the release of DHBs into the aqueous phase and can be used for AOPs. The production of center dot OH was investigated using a spin-trapping electron paramagnetic resonance technique (5-dimethyl-1pyrroline-N-oxide/center dot OH) in the first minute of the reaction and a high-performance liquid chromatography-fluorescence technique (coumarin/7-hydroxycoumarin) for 20 min. The center dot OH yield achieved using insoluble tannins from Pinus radiata bark was higher than that achieved using catechin to drive the Fenton reaction. The Fenton-like system driven by insoluble tannins achieved 92.6 +/- 0.3 % degradation of atrazine in 30 min. The degradation kinetics of atrazine was linearly correlated with center dot OH production. The increased reactivity in center dot OH production and insolubility of the ligand are promising for the development of a new technique for degradation of pollutants in wastewater using heterogeneous Fenton systems.