Impact of drying process on kraft lignin

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openAccess

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Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2021

Major/Subject

Mcode

Degree programme

Language

en

Pages

11
159-169

Series

Journal of Materials Research and Technology, Volume 12

Abstract

Kraft lignin, an industrially available by-product from the pulp and paper industry, has revealed enormous potential to be valorised into a wide range of chemicals and biomaterials in the last two decades. However, the understanding of lignin chemistry remains challenging due to its chemical complexity. The goal of this work was to investigate the effect of drying temperature on the chemical, physical, and hygroscopic properties of hardwood kraft lignin isolated from industrial black liquor and elucidate the molecular interactions occurring between water and kraft lignin. Sorption-desorption isotherms determined by dynamic vapour sorption (DVS) technique revealed that the drying process considerably affected the hygroscopicity of the lignin polymer. Moreover, analytical pyrolysis (Py-GC-MS), dynamic NIR spectra collected as a function of relative humidity (0-95%) during sorption-desorption cycles and principal component analysis (PCA), evidenced chemical differences between lignin dried at room (25 °C) temperature and mild oven (55 °C) conditions. The main spectral changes associated with the water sorption in kraft lignin samples were analyzed using difference spectrum technique. 2D NIR spectral correlation analysis provided water sorption mechanism of lignin polymer, disclosing for the first time the sequential order in which water vapour molecules interact with active sorption sites in kraft lignin.

Description

Funding Information: The author gratefully acknowledges the European Commission for funding the InnoRenew project [Grant Agreement # 739574 ] under the Horizon 2020 Widespread-Teaming program, the Republic of Slovenia (investment funding from the Republic of Slovenia and the European Union European Regional Development Fund) and infrastructural ARRS program IO-0035. Part of this work was conducted during the project Multi-spec (BI-IT/18-20-007) funded by ARRS . Additionally, O.G. is grateful for the financial support received from the University of the Basque Country (post-doctoral grant of Ms. Gordobil DOCREC18/29) and R.H. acknowledges to the Department of Education of the Basque Government (post-doctoral grant). Publisher Copyright: © 2021 The Authors.

Keywords

2D-COS, Drying temperature, DVS, Hardwood kraft lignin, NIR spectroscopy

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Citation

Gordobil , O , Herrera , R , Poohphajai , F , Sandak , J & Sandak , A 2021 , ' Impact of drying process on kraft lignin : Lignin-water interaction mechanism study by 2D NIR correlation spectroscopy ' , Journal of Materials Research and Technology , vol. 12 , pp. 159-169 . https://doi.org/10.1016/j.jmrt.2021.02.080