Degradation of steam-exploded lignin from beech by using Fentonʹs reagent

Steam-exploded lignin from beech was obtained from a bench apparatus and fully characterized. The treatment of this lignin with hydrogen peroxide and ferrous sulfate (1.5, 5.8, 11.65, and 31.32 mmol of the reagent) induces an extensive degradation in the native lignin. The reaction was monitored using ultraviolet spectroscopy and the registered spectra showed that typical absorptions of lignin at 207, 230, and 276 nm disappeared. The analysis of the residue through gel permeation chromatography showed that lignin was extensively degraded. The treatment with 5.8 mmol of the reagent induced the formation of a trace of both polymeric material and small molecular weight degradation products. The treatment of recycled paper where 27% lignin was present gave extensive degradation of lignin.