Viable and integrated reaction and separation techniques are necessary for effective lignin valorization to generate high added-value monomeric phenolics like syringaldehyde and vanillin. Extensive research has been directed toward techniques like extraction, membrane filtration, chromatographic separation, and the combination of these approaches to achieve this objective.

Abstract

Lignin is one of the most abundant bio-aromatic molecular resources, but it is currently underutilized for energy production in the pulp and paper industry. Unlocking the full potential of lignin could have a significant impact on reducing environmental pollution, increasing the use of renewable resources, and achieving environmentally beneficial economic growth. However, effective lignin valorization requires viable and integrated reaction and separation processes to produce high value monomeric phenolics, such as vanillin and syringaldehyde. The aim of this short review is to summarize the studies on different separation methods of lignin derivatives obtained from black liquor, including extraction, membrane filtration, chromatographic separation, and the combination technologies.