Carbonaceous structural changes of wood induced by microwave irradiation

Abstract

Abstract The objective of this study was to investigate the carbonization induced by microwave treatment (MWT) of spruce (Picea sp.) wood, which was treated in a domestic microwave oven at 2.45 GHz. Structural changes were observed by elemental analysis, thermal analysis, and by IR and Raman spectroscopy. The degradation of the samples was completed within 3 min. The carbonization was comparable to that caused by heat treatment at ca. 420°C. In the MWT samples, a graphitic layer was not detected, which behaves as a sensitizer for MW irradiation and sometime elevates the temperature drastically. This study shows that MWT leads to a carbonaceous material, and that the carbonization levels off with the loss of heat-inducing functional groups, such as O-H, CO-OH, C=O, upon MW irradiation. MWT is better suited as a kind of controlled and short pretreatment method before carbonization. Its suitability for porous absorbents should be investigated.