Leaching of alkali and alkaline earth metallic species (AAEMs) with phenolic substances in bio-oil and its effect on pyrolysis characteristics of moso bamboo

Acids present in bio-oil are considered to be effective agents to remove alkali and alkaline earth metallic species (AAEMs) from biomass, therefore affecting biomass pyrolysis. This study assessed whether phenols in bio-oil have a similar effect, with the pyrolysis characteristics of leached bamboo investigated using water and two typical phenolic compounds, phenol and guaiacol. Results confirmed that phenols have an important role in the removal of AAEMs, removing 96.4-96.6% of K, 84.6-85.4% of Mg, 77.2-81.9% of Na, and 66.7-69.1% of Ca. TG-FTIR results showed that phenolic leaching enhanced the pyrolytic release of volatile components of bamboo (H2O, CO2, CO, CH4, and carbonyl (C = O)-containing components), increased the temperature of pyrolysis peaks and decreased the activation energy, while increasing separation of the hemicellulose and cellulose pyrolysis zone. The results of Py-GC/MS showed that phenolic leaching reduced the production of acids but promoted the formation of anhydrosugars in bio-oil, indicating that phenolic leaching of AAEMs has a positive effect on the pyrolysis utilization of bamboo.