Figure 3 shows the properties of pyrolytic lignin (yield, acidity, C/H atomic ratio
and heating value) extracted with different water:bio-oil ratios. As shown in Figure 3A,
higher water:bio-oil ratios resulted in lower yields of pyrolytic lignin, indicating that
more polar-compounds in bio-oil dissolved into the aqueous phase. This loss of some
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light-phase compounds caused the decease in the acidity of the pyrolytic lignin, as show
in the Figure 3. The acidity decreased with the increasing water:bio-oil ratios from 5:1
to 15:1, then converged around 13 mg KOH/g oil.