One-pot mild fabrication of magnetic lignin-based carbon-rich materials using deep eutectic solvent for efficient dye removal

In this study, a deep eutectic solvent (DES) was utilized for the one-step mild preparation of a magnetic lignin-based carbon-rich material, C-AL@Fe 3 O 4 , for the removal of malachite green (MG). The key factors influencing the preparation process and adsorption performance were systematically examined, including the water content in DES, lignin/DES ratio, reaction temperature, and reaction time. Characterization confirmed the successful synthesis of C-AL@Fe 3 O 4 with enhanced magnetic and adsorption properties. Adsorption experiments demonstrated an endothermic chemisorption process towards MG dye, with a monolayer Q max of 529.02 mg/g, driven by electrostatic interactions, hydrogen bonding, and π-π interactions. Moreover, C-AL@Fe 3 O 4 exhibited selective and reusable adsorption performance for cationic dyes. This study presents a green method for the one-pot mild preparation of magnetic lignin-based carbon-rich materials with promising adsorption performance, offering potential for wastewater treatment and enhancing the use of lignin resources. This adheres to the “4S workflow” (converting sustainable/recyclable resources into biodegradable sustainable products, using sustainable technology throughout the process to create a sustainable environment).