Acetic acid has the highest peak area detected amongst the other organic acids in the bio-oil. The peak area of acetic acid is mostly reduced with Al-MCM-41 catalyst, and BRHA catalyst having almost no effect on the reduction of acetic acid when compared to the non-catalytic run. This agrees with the study from Samolada et al., who reported a reduction in acetic acid content in bio-oil on using fresh Al-MCM-41 catalyst in a fixed bed reactor [52]. Adam et al. also reported that Al-MCM-41 increased the acetic acid production for fast pyrolysis, but observed a decreased for catalytic pyrolysis with a lower heating rate [31]. This result is in agreement with our study, as the heating rate in this work is moderate.