Semivolatile organic compounds in the products from hydrothermal carbonisation of sugar cane bagasse and vinasse by gas chromatography-mass spectrometry

Abstract

In this paper, sugar cane bagasse and vinasse were subjected to a hydrothermal carbonisation process (HTC), under different reaction conditions (temperature, time and percentage of phosphoric acid addition). Semivolatile organic compounds (SVOC) were extracted from both the products obtained by the HTC: hydrochar (HC) and process water (PW), and identified by gas chromatography together with mass spectrometry (GC–MS). The main SVOC in HC and PW are phenols, carboxylic acids, ketones, and particularly to products obtained using vinasse, they contain nitrogen compounds, sterols and fatty acids. Higher temperature and acid percentage addition respectively brought greater aromatisation and functionalisation in HC. Furthermore, the addition of phosphoric acid within the HTC led to the decrease of phenolic compounds and furans, and an increase in the formation of carboxylic acids and ketones in the PW. In the PW were found important compounds such as 4-methyl-3-pentenoic acid and 4-hydroxy-butanoic acid to industry.