High-purity lignin fractions and nanospheres rich in phenolic hydroxyl and carboxyl groups isolated with alkaline deep eutectic solvent from wheat straw

Xin Yue, Terhi Suopajärvi, Shirong Sun, Otto Mankinen, Atte Mikkelson, Harri Huttunen, Sanna Komulainen, Idamaria Romakkaniemi, Juha Ahola, Ville Veikko Telkki, Henrikki Liimatainen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

A combined pretreatment based on alkaline deep eutectic solvent (DES) of K2CO3 and glycerol and sequential acid fractionation was developed to extract reactive lignin from wheat straw biomass. This process exhibited excellent purification performance in lignin isolation, and the lignin fractionated at low pH displayed high reactivity, having hydroxyl and carboxyl groups up to 9.60 and 2.52 mmol/g, respectively. Silica was selectively separated and removed during the precipitation stage, avoiding the “silica interference”. Moreover, DES-lignin nanospheres created by self-assembly using lignin fractions obtained by acid precipitation possessed a high zeta potential, large particle size and high content of hydrophilic groups. Overall, the findings related to the dissociation mechanism and fractionation of reactive lignin during alkaline DES pretreatment and the acid sequence precipitation are crucial for facilitating lignin valorization in high-added value products.

Original languageEnglish
Article number127570
JournalBioresource Technology
Volume360
Early online date3 Jul 2022
DOIs
Publication statusE-pub ahead of print - 3 Jul 2022
MoE publication typeA1 Journal article-refereed

Keywords

  • Alkaline deep eutectic solvent
  • High-purity lignin
  • Phenolic hydroxyl
  • Sequential acid fractionation
  • Wheat straw

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