Document Type

Article

Publication Date

8-22-2026

Publication Source

Polymer Bulletin

Abstract

While bio-based hydrogels derived from lignin and chitosan are promising sustainable adsorbents, their practical application is hindered by poor mechanical stability. This study addresses this limitation by synthesizing lignin-chitosan hydrogels using vanillin as a green, bio-derived crosslinker via a facile solution-casting method. The formation of imine (Schiff base) linkages between the aldehyde groups of vanillin and the primary amines of chitosan was confirmed by FTIR spectroscopy (C = N stretching at ~ 1602 cm− 1). SEM and TGA results demonstrated a reduction in the pore size of the crosslinked hydrogel and an enhanced residual thermal mass. Rheological and tensile testing revealed robust network reinforcement, with a 32.3% increase in tensile strength compared to non-crosslinked analogs. Despite a slight decrease in swelling capacity due to a denser network, the crosslinked hydrogels exhibited versatile, dual-functional adsorption, effectively sequestering both cationic and anionic dyes. These achieved ~ 95% removal of methylene blue, ~ 94% removal of rhodamine 590 chloride, and ~ 92% removal of methyl orange. The adsorption adhered to the Langmuir isotherm and pseudo-first-order kinetics, suggesting a controlled, monolayer chemisorption process. These findings highlight the potential of vanillin-mediated crosslinking to produce high-performance, fully bio-based adsorbents for sustainable wastewater remediation.

ISBN/ISSN

0170-0839 (print); 1436-2449 (electronic)

Document Version

Published Version

Comments

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

DOI: https://doi.org/10.1007/s00289-026-06625-w

Publisher

Springer Nature

Volume

83

Peer Reviewed

yes

Issue

11

Keywords

Lignin hydrogel, Chitosan hydrogel, Bio-based adsorbent, Vanillin crosslinker, Dye removal, Schiff base

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