ABSTRACT The limited adsorption performance of pristine lignin, together with its frequent dependence on sophisticated or energy‐intensive modification strategies, represents a significant barrier to the development of sustainable lignin‐based adsorbents for dye‐contaminated wastewater treatment. Herein, a facile and environmentally benign synthesis of a lignin–manganese oxide (lignin–MnO) nanocomposite is presented via an acetone–water nanoprecipitation route combined with in situ KMnO 4 ‐induced oxidation. Unlike previously reported lignin–MnO 2 or surface‐coated manganese oxide systems, this approach enables the formation of embedded lower‐valence MnO nanodomains within lignin nanoparticles through a carbonization‐ and template‐free route. This hybrid architecture facilitates efficient adsorption of bulky aromatic dyes under near‐neutral pH conditions through heterogeneous, stacking‐dominated interactions. Structural and surface analyses (SEM–EDX, XRD, XRF, FTIR, and BET) confirm the formation of a stable mesoporous hybrid material with excellent colloidal stability. Using malachite green as a model dye, the lignin–MnO nanocomposite exhibits a high adsorption capacity of 277.78 mg g − 1 at near‐neutral pH. Adsorption follows pseudo‐second‐order kinetics ( R 2 = 1.00) and the Freundlich isotherm ( R 2 = 0.9629), indicating heterogeneous and multilayer adsorption dominated by π–π stacking interactions assisted by hydrogen bonding and weak electrostatic attraction. This work demonstrates a scalable, low‐energy lignin–MnO hybridization strategy for sustainable wastewater remediation.
Aryana et al. (Sun,) studied this question.