Lignin activation with selected ionic liquids based on kinetic and thermodynamic analyses

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Lignin, a biopolymer, offers potential for sustainable materials but requires functionalization.
• Existing methods for lignin modification often lack selectivity or degrade the polymer structure.

Purpose of the Study:

• To investigate ionic liquids (ILs) for activating lignin, enhancing its carbonyl content.
• To enable lignin's use as a sustainable alternative in advanced materials and electrochemical applications.

Main Methods:

• Selective oxidation of lignin using ILs as activators and controlled air supply.
• Thermal decomposition analysis using thermogravimetric analysis (TGA), differential thermogravimetric analysis (DTG), and differential thermal analysis (DTA).
• Kinetic modeling of thermal degradation using the Coats-Redfern method.

Main Results:

• Activation with ILs significantly increased carbonyl (quinone) group content in lignin.
• Enhanced lignin exhibits potential as a reversible proton and electron acceptor for electrochemical applications.
• Degradation kinetics and thermal stability were analyzed, with activation energy ranging from 66.691 to 309.389 kJ/mol.

Conclusions:

• Ionic liquid-mediated activation is a viable strategy to enhance lignin's functionality for materials science.
• Balancing lignin's degradation kinetics and structural properties is crucial for optimizing its reactivity.
• Modified lignin shows promise for sustainable electrode materials and composite systems.