Figure 7.

(a) Schematic illustration of the preparation of polypyrrole@lignin composites and their applications in electrical sensing and metal ion adsorption. Reproduced with permission from ref. [87]. Copyright 2022, Elsevier. (b) Schematic illustration of the synthesis of a novel lignosulfonate-modified graphene hydrogel and its ultra-high adsorption capacity for Cr (VI) in wastewater. Reproduced with permission from ref. [89]. Copyright 2021, Elsevier. (c) Schematic illustration of sequential application of lignin-based composite hydrogels for heavy metal ion adsorption and chemiluminescence. Reproduced with permission from ref. [90]. Copyright 2022, Elsevier.