After removing inorganic metals from poplar wood via demineralization with diverse solvents [HCl, HF, distilled water (DI-H 2 O)], respectively, changes in decomposition characteristics, maximum decomposition rate (V max ) and corresponding temperature (T max ), were observed using thermo-gravimetric analysis. Activation energies calculated by differential method were ranged from 160.5 to 188.1kJ/mol for raw biomass, 157.5 to 233.2kJ/mol for HCl-biomass, 172.3 to 220.3kJ/mol for HF-biomass and 127.9 to 229.0kJ/mol for DI-H 2 O-biomass. The demineralized samples were also subjected to TGA analysis after impregnation with K, Ca, and Mg. Interestingly; only potassium had catalytic effects on cellulose decomposition. A significant decrease in T max was attributable to an increase in potassium content.