Triacetonamine formation in a bio-oil from fast pyrolysis of sewage sludge using acetone as the absorption solvent

A sewage sludge sample was pyrolyzed in a drop tube furnace at 500 °C and sweeping gas flow rate of 300 cm3/min. Triacetonamine (TAA) was detected with GC/MS as major component in the resulting bio-oil using acetone as the absorption solvent and proven to be a product from the reaction of NH3 in the bio-oil with the absorption solvent acetone. TAA yield increased with storage time and reached a level about 28.4% (% sludge fed, daf) after 175 h. Since the reaction of pure NH3 with acetone does not proceed, some species in the bio-oil must catalyze the reaction of NH3 with acetone. TAA was isolated in a high yield (27.9%, daf) and high purity (80.4%) by column chromatography with different solvents, including mixed solvents, as eluants. The study revealed the possibility of sewage sludge as potential resource of TAA.