Pore Development during the Carbonization Process of Lignin Microparticles Investigated by Small Angle X-ray...

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• The application of low-cost carbon black derived from lignin is contingent upon its material properties.
• Lignin's properties are influenced by its source and processing conditions, necessitating controlled methods for carbon production.

Purpose of the Study:

• To investigate the impact of thermal processing on the development of carbon materials from various technical lignins.
• To characterize the evolution of pore structure, graphitization, and surface properties of lignin-derived carbons.

Main Methods:

• Thermostabilization and stepwise heat treatment of four technical lignins up to 2000 °C.
• Characterization using X-ray scattering, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy.

Main Results:

• Lignosulfonate-based carbons showed complex nanopore and mesopore development.
• Organosolv, kraft, and soda lignin-based carbons exhibited steadily increasing pore sizes with heat treatment.
• Significant increases in pore size (0.5-2 nm) and inner surface area occurred between 1200 °C and 1600 °C, with a shift towards graphite.

Conclusions:

• Heat treatment at 1600 °C is potentially sufficient for many lignin-derived carbon applications, optimizing energy use.
• The degree of graphitization and crystallite size increase with higher heat treatment temperatures.
• Tailoring lignin source and thermal processing allows control over carbon material properties.