Production of bio-oils and bio-char from Arundo donax through microwave assisted pyrolysis in a multimode batch reactor

Several organs (rhizomes, stems and leaves) of Arundo donax, a perennial cane ubiquitary in the mediterranean area, were pyrolyzed using a microwave assisted pyrolysis with carbon as microwave absorber and different reaction conditions. Relevance of the organs on the yields and products was shown and, as a function of the conditions adopted, these results may be emphasized or reduced. In all experiments a small gas (4.6%) and a large biochar production (up to 62.9%) were obtained while bio-oil was formed in amount up to 40.9% as a one-phase dark brown liquid having low viscosity. These liquids were characterized through several techniques among which FT-IR, 1H NMR, and a quantitative GC–MS analysis. These bio-oils contained a huge amount of aromatics, acetic acid, furanes and, sometimes, levoglucosan (up to 47.6 g/L). The microwave assisted pyrolysis of waste from several organs of Arundo donax appears as an interesting way to dispose these materials and to obtain useful biochemicals and fuels through a fast pyrolysis process.