Study of the pectin influence on bio-oil produced from sisal residue pyrolysis

The published works on biomass pyrolysis usually relate the bio-oil composition to the thermal degradation of cellulose, hemicellulose, and lignin regardless of the extractive content in the biomass composition. Extractives comprise fats, waxes, alkaloids, proteins, phenolics, simple sugars, pectins, gums, resins, terpenes, starches, glycosides, saponins, and essential oil, with pectin being one of those with the highest concentration. This work aims to investigate the effect of pectin on the bio-oil produced in a fast pyrolysis system. The biomass used was sisal residue, whose pectin represents approximately 1/3 of the original biomass. Pectin was extracted from the biomass considering extraction time (25–65 min), the medium pH (2.0–4.7), and the biomass/water ratio (8–12 %). All pyrolysis tests used the same operating conditions (reaction time: 10 min, argon flow rate: 50 mL.min−1, and reaction temperature: 450 °C). The bio-oil yield was not influenced by the pectin content present in the biomass. The characterization by FTIR, 1H NMR and 13C NMR, and GC-MS indicated that, although the pectin content does not influence the types of functional groups present in the bio-oil, it does affect the concentration, new species appearance, and disappearance of others.