Effect of Pyrolysis Temperature on the Characterisation of Dissolved Organic Matter from Pyroligneous Acid

Area of Science:

• Environmental Chemistry
• Biogeochemistry
• Organic Geochemistry

Background:

• Dissolved organic matter (DOM) plays a crucial role in environmental nutrient and pollutant transformations.
• Pyroligneous acid (PA), a byproduct of biomass pyrolysis, contains DOM that can influence environmental processes.

Purpose of the Study:

• To investigate the effects of varying pyrolysis temperatures on the composition and evolution of DOM derived from eucalyptus PA.
• To understand how temperature-induced changes in PA-DOM affect its environmental behavior.

Main Methods:

• DOM solutions were extracted from eucalyptus PA produced at five pyrolysis temperature ranges (240-420 °C).
• Analysis employed Fourier transform infrared spectroscopy, gas chromatography-mass spectroscopy, and fluorescence spectroscopy.
• Two-dimensional correlation spectroscopic analysis was used to assess component sensitivity.

Main Results:

• Dissolved organic carbon content significantly increased with rising pyrolysis temperature (p < 0.05).
• Humic-acid-like substances constituted the dominant fraction (71.34-100%) of DOM.
• Other fluorescent components (fulvic-acid-like, microbial by-products, protein-like) diminished at higher temperatures (>370 °C).
• Humic-acid-like substances showed increased sensitivity with rising pyrolysis temperatures.

Conclusions:

• Pyrolysis temperature is a key factor controlling the composition and characteristics of PA-derived DOM.
• Increasing pyrolysis temperatures lead to a dominance of humic-acid-like substances, suggesting altered environmental implications.
• This study offers insights into the evolution of DOM from pyroligneous acid under different thermal conditions.