4. Conclusion
This study investigated the determination of strong and weak
acidic components in bio-oil via a non-aqueous potentiometric
titration. The aim of differentiating the carboxylic acids and phenolic
groups were successfully completed via our developed method.
The heavy carboxylic acids in bio-oil from wood represented about
29–45% (mol basis) of all carboxylic acids. The phenolic groups existed
in bio-oil from the mallee wood were primarily in big aromatics,
accounting approximately 97% (mol basis) of all phenolics. It
was noteworthy that the portion of heavy carboxylic acids in
bio-oil from leaves was much higher than that of bio-oils from
wood and bark. The large phenolics accounted for more than 90%
(mol basis) of all phenolics in all the three kinds of bio-oils. The
titration method developed in this study provides a good means
to measure the abundances of both light and heavy carboxylic
acids and phenolics in bio-oil.