Influence of zinc chloride addition on the chemical structure of bio-oil obtained during co-pyrolysis of wood/synthetic polymer blends

The chemical structure of liquid products of the pinewood sawdust (W) co-pyrolysis with polystyrene (PS) and polypropylene (PP) with and without the zinc chloride as an additive was investigated. The pyrolysis process was carried out at 450 degrees C with the heating rate of 5 degrees C/min. The yield of liquid products of pyrolysis was in the range of 37-91 wt% and their form was liquid or semi-solid depending on the composition of the wood/polymer blend. The zinc chloride addition to wood/polymer blends has influenced the range of samples decomposition as well as the chemical structure of resulted bio-oils. All bio-oils from wood/polypropylene blends were two-phase (liquid and solid). Contrarily, all bio-oils obtained from biopolymer/polypropylene blends with zinc chloride added were yellow liquids. All analyses proved that the structure and the quality of bio-oil strongly depend on both the composition of the blend and the presence of ZnCl2 as an additive. The FT-IR analyses of oils showed that oxygen-containing groups and hydrocarbons content highly depend on the composition of biomass/synthetic polymer mixture. The fractionation of bio-oils by column chromatography with four different solvents was followed by GC-M5 analysis. Results confirmed the significant removal and/or transformation of oxygen-containing organic compounds due to the zinc chloride presence during pyrolysis process. (C) 2009 Elsevier Ltd. All rights reserved.