Lignin-based hybrid materials in wastewater cleanup

Lignin is the second most abundant source of aromatic biopolymer next to cellulose. Till now, it has been regarded as waste material and various industries have been discarding it directly into the environment. However, with the current advancement in lignin chemistry, pre-treatment and processing methods, and various beneficial characteristics have been discovered including bioactivities properties like antimicrobial activities, optical properties, redox, flocculants, and metal ions chelating activities. This has opened a new field for synthesizing modified or functionalized lignin materials such as lignin-based nanohybrids. In this chapter, we have illustrated available sources of lignin, its extraction and methods of modification (with conventional and advanced processes). Furthermore, we have also discussed the synthesis and modification of lignin- and lignin-based nanohybrids. The various applications of lignin- and lignin-based nanohybrids as adsorbents, photocatalysts, flocculants, and antimicrobial agents are also discussed.