Electrooxidation of lignin to produce value-added chemicals as an effective valorization technique

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Volume Title

School of Chemical Engineering | Master's thesis

Date

2024-11-07

Department

Major/Subject

Chemical and Process Engineering

Mcode

Degree programme

Master's Programme in Chemical, Biochemical and Materials Engineering

Language

en

Pages

52

Series

Abstract

The growing demand for alternative energy sources and sustainable industrial processes has highlighted the potential of lignin, a byproduct of biorefineries and pulp production, as a valuable feedstock for the production of high-value chemicals. This study explores the electro-oxidation of lignin as a green, efficient method for lignin valorization under ambient conditions. By employing a metal-based catalyst, the process successfully degrades lignin into aromatic compounds such as 2,3-dihydrobenzofuran (DHB), vanillin (VA), 2-methoxy-4-vinyl phenol (MVP), and 4-hydroxy-3,5-dimethox-ybenzaldehyde (HDMB), with the yield of 5.41%, 1.08%, 1.01% and 1.00%, respectively. The overall yield of lignin conversion reached 11.17%, with 9.72% being aromatic products, aligning with and surpassing existing literature values. Cyclic voltammetry confirmed the successful oxidation of lignin and provided insights into the mass-transfer-controlled reaction mechanism. Additionally, gel permeation chromatography (GPC) analysis showed a significant reduction in lignin molecular weight from 4333 g/mol to 551 g/mol, further validating the degradation of lignin into smaller compounds. These results demonstrate the potential of electro-oxidation as an effective method for lignin valorization, contributing to the circular economy by transforming a low-value byproduct into commercially relevant compounds. Future research will focus on optimizing the process conditions and exploring its scalability for industrial applications, as well as refining product separation techniques for downstream use.

Description

Supervisor

Li, Yongdan

Thesis advisor

Bagheri, Marzieh

Keywords

lignin valorization, electro-oxidation, metal-based catalyst, aromatic compounds, cyclic voltammetry, sustainable process

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