STRUCTURAL CHANGES OF MILLED WOOD LIGNIN IN TREATMENT WITH IRON-BASED BIOMIMETIC COMPOUND

摘要

The ability of fungal enzymes in degradation of lignin has promoted the exploration of simple compounds which can simulate the function of the enzymes. Iron-based biomimetic compound which is selective catalysts in delignification has been a hot topic for a decade. In the present research, a novel biomimetic system which uses a transition metal (Fe) and a chelate compound (CA) to form a coordination compound was developed. This complex can catalyze H2O2 to produce hydroxyl radicals (·OH) and superoxide radicals (·O2) which can decompose wide ranges of polycyclic aromatic hydrocarbons. The structural changes of lignin during the degradation by this biomimetic compounds was investigated using milled wood lignin (MWL) from triploid ofpopulus tomentosa as reaction substrate. In order to understand the changes of chemical structure of the MWL, the combination of FT-IR and (GC-MS) were applied as the analytic methods. It is found that this biomimetic system is very efficient in degrading MWL. The FT-IR and GC-MS analyses indicate that a large number of aromatic low molecular aromatic compounds with hydroxyl, carbonyl and carboxyl groups are produced after the treatment. Finally, a conclusion can be drawn that biomimetic treatment lead to cleavage of the linkages as β-O-4, β-β, and β-5 etc., with the increase of low molecular aromatic compounds. Therefore, the iron-based biomimetic compound is an attractive approach to pulp delignification. It will be a promising delignification reagent in pulp bleaching.