3.2 water content in bio-oils
The water contents in the bio-oil obtained from pyrolysis of untreated and pretreated biomass as determined by karl Fischer are indicated in fig. 2. lt can be observed that the amount of water in the bio-oil of untreated(19.9%),hot water pretreated(17.3%),and torrefied (19.4%) biomass was similar in quantity.However, the content of water increased in the bio-oils of the biomass which were pretreated with sulphuric acid(29%) and ammonium phosphate(34.39%). This reveals that acid and salt doping of biomass favoured dehydration reactions along with intermolecular and intermolecular bond scission of cellulose which led to increased water content in the liquid after their pyrolysis(Julien et al., 1993). The water in the acid pretreated bio-oil(29%)can be attributed to the release of H₂O from the fragmentation reactions of cellulose, hemicellulose, or lignin(Dobele et al., 2002).Similar to the present study.Scott et al.(2002),also reported an increased water yield after pretreatment of the biomass by dilute acid.The salt pretreatment may have also modified the cellulose structure leading to enhanced production of water through dehydration reaction(Di Blasi et al.,(2007).