husk treated with water present higher T2 than untreated agulhinha rice husk, but there is no evidence of gain on its activation energy. And finally, all acid treatments increased both activation energy and T2 of untreated agulhinha rice husk from 127 kJ mol−1 and 168 ◦C, respectively, to values as high as 146.8 kJ mol−1 and 310 ◦C, respectively. In addition to the gain on activation energy caused by removal of metallic impurities, chemical treatment performed under pressure and temperature might have removed other more thermally unstable organic compounds from the rice hus