Rapid and Direct Preparation of Lignin Nanoparticles from Alkaline Pulping Liquor by Mild Ultrasonication

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2019
Major/Subject
Mcode
Degree programme
Language
en
Pages
19925 − 19934
Series
ACS Sustainable Chemistry and Engineering, issue 7
Abstract
The production of lignin nanoparticles (LNPs) has opened new routes to the utilization of lignin in advanced applications. The existing challenge, however, is to develop a production method that can easily be adapted on an industrial scale. In this study, we demonstrated a green and rapid method of preparing LNPs directly from a sulfur-free alkaline pulping liquor by combining acid precipitation and ultrasonication. The combined method produced spherical LNPs, with a hierarchical nanostructure and a highly negative surface charge, within only 5 min of sonication. The mild, rapid sonication was achieved by sonicating directly without prior drying of the acid-precipitated and dialyzed lignin. Optimization of the method revealed the potential for minimizing acid consumption, shortening the dialysis time, and processing directly the alkaline liquor with as much as 20 wt % lignin. The isolated LNPs were stable during storage for 180 days, at a pH range of 4-7, and in a dispersing medium below 0.1 M NaCl. The LNPs also displayed excellent emulsifying properties, stabilizing oil-in-water emulsions. Thus, this simple and energy-efficient method opens a sustainable, straightforward, and scalable route to the production of organic solvent-free LNPs, with high potential as interface stabilizers of multiphase systems in the food and medical industries.
Description
Keywords
acid precipitation, alkaline pulping liquor, BLN lignin, emulsion, lignin nanoparticle, ultrasonication
Other note
Citation
Agustin, M B, Penttilä, P A, Lahtinen, M & Mikkonen, K S 2019, ' Rapid and Direct Preparation of Lignin Nanoparticles from Alkaline Pulping Liquor by Mild Ultrasonication ', ACS Sustainable Chemistry and Engineering, vol. 7, no. 24, pp. 19925 − 19934 . https://doi.org/10.1021/acssuschemeng.9b05445