Extraction and characterisation of lignin from residues of Mexican Ocote pine (Pinus montezumae Lamb.) for biofuel production

Abstract

The objective of this research was to extract lignin from residual lignocellulosic biomass of Ocote pine softwood (Pinus montezumae Lamb.) in the south-southwestern region of the Mexican Republic and to determine its potential as raw material to obtain biofuels. The lignin obtained was characterised by Fourier Transform Infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA), Higher Heating Value (HHV) analysis and elemental analysis. The Kraft process was applied for biomass delignification because it is most commonly used in the paper industry worldwide, using sodium hydroxide (NaOH) and sodium sulphide (Na₂S) to extract the lignin from the fibres of the forest residues (sawdust and bark) in a 600 mL Parr reactor. The lignin extracted from pine sawdust obtained a better calorific value (28.75 MJ kg⁻¹) than that recovered from the bark (23.61 MJ kg⁻¹). The yield of lignin obtained from 50 g of bark, 5 g, was higher than that obtained from 50 g of sawdust, 2 g. The obtained lignin can be further processed to generate higher value-added products such as liquid biofuels.

Keywords:

• Biomass
• lignin
• characterisation
• FT-IR
• HHV
• TGA
• elemental analysis

Acknowledgements

This research was financially supported by the multidisciplinary research project SIP 2188, module SIP 20231028. Special recognition to the National Laboratory for the Development and Quality Assurance of Biofuels (LaNDACBio), for allowing access to the laboratory facilities. Ernesto García-Cisneros also thanks CONACyT for scholarship number 681224 for his doctoral studies at the IPN.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Consejo Nacional de Ciencia y Tecnología [681224] and Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional [20231028].