Nanomaterials from lignocellulosic biomass : tailorable synthesis via surface functionalization and self-assembly mechanisms

This dissertation presents an innovative lignocellulosic biomass-based refinery based on deep eutectic solvents (DESs) and specialized for biomass-based nanomaterials synthesis Particularly, this work has the focus on lignin nanoparticles (LNPs) and lignin-containing cellulose nanofibrils (LCNFs). First, the lignin self-assembly in the formation of nanolignin was illustrated via combining the experimental data and the theoretical calculations. A modeling method applying Derjaguin-Landau-Verwey-Overbeek's (DLVO) theory and population balance equation was developed to predict the particle size of LNPs formed in different conditions. Secondly, a diol-based DES pretreatment platform was developed for efficient switchgrass fractionation and lignin functionalization. The cellulose-rich pulp with most xylan and lignin removed can be utilized in high concentration enzymatic sugar production. The recovered lignin can be converted into morphology-tunable (compact-/hollow-dominant) LNPs due to the variation of [beta]-O-4 preservation and modification determined by diol structure. Thirdly, one-pot DES pretreatment and functionalization (PEGylation and maleilation) were demonstrated as a suitable process to prepare modified cellulose-rich pulp and lignin for nanomaterials upgrading. The resultant PEGylated cellulose-rich pulp has high cellulose content when the maleilated pulp can be converted into fine LCNF via enzymatic treatment and fast ultrasonication. The maleilated lignin with narrow molecular weight distribution can easily form into uniform LNPs. Lastly, the one pot co-maleilation and biomass pretreatment at low temperature was investigated. LCNF with high aspect ratio and sufficient surface charges were produced afterward. The LCNF combined with a Copper (II)-based organic complex can be utilized as sustainable and cost-effective adsorbents in per- and polyfluoroalkyl substances (PFAS) removal.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Biological engineering (MU)

Grantor dc:publisher

University of Missouri--Columbia

Year dc:date.issued

2024

Author dc:creator

• Li, Qianwei

Advisor dc:contributor.advisor

• Wan, Caixia

Language dc:language.iso

eng, English

DOI

https://doi.org/10.32469/10355/105035

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/105035