Influence of the Method of Fe Deposition on the Surface of Hydrolytic Lignin on the Activity in the Process of Its Conversion in the Presence of CO2

Hydrolytic lignin is one of the non-demanded carbon materials. Its CO2-assisted conversion is an important way to utilize it. The use of the catalysts prepared by metal deposition on the surface of hydrolytic lignin makes it possible to apply milder conditions of the conversion process with CO2 and to improve the economic indicators. The development of methods of deposition of the active phase is a problem of high importance for any heterogeneous catalytic processes. This work aimed at investigating the influence of the conditions of iron deposition on the surface of hydrolytic lignin on the process of CO2-assisted conversion of lignin. Different Fe precursors (Fe(NO3)(3), FeSO4, Fe-2(SO4)(3)), solvents (water, isopropanol, acetone, and ethanol), and concentrations of the solution were used; the properties of Fe/lignin composites were estimated by SEM, EDX, TEM, XRD methods and catalytic tests. All the prepared samples demonstrate a higher conversion compared to starting lignin itself in the carbon dioxide-assisted conversion process. The carbon dioxide conversion was up to 66% at 800 degrees C for the sample prepared from Fe(NO3)(3) using a twofold water volume compared to incipient wetness water volume as a solvent (vs. 39% for pure lignin).

Automated summary

This study aimed to investigate the influence of iron deposition conditions on the surface of hydrolytic lignin on the process of CO2-assisted conversion. The results showed that all prepared samples demonstrated higher conversion rates compared to pure lignin in the carbon dioxide-assisted conversion process.