Preparation of magnetic lignin-based adsorbents and its adsorption properties for dyes

In this study, the renewable magnetic lignin-based material with good properties and environmental friendliness was successfully prepared and used for the treatment of wastewater. Lignin nanospheres (LNS) were prepared from stearyl chloride esterified alkali lignin via self-assembly in the mixture and raspberry-like magnetic lignin microspheres (Fe3O4@SiO2-LNS) was successfully prepared by grafting LNS onto the surface of Fe3O4@SiO2 particles by chemical crosslinking, then was used as absorbent for Methylene blue (MB) and Rhodamine B (RhB) dyes. The results indicated that the Fe3O4@SiO2-LNS had excellent adsorptivity in alkaline solution, and the maximum adsorption capacities for MB and RhB were 258.40 mg·g-1 and 124.38 mg·g-1 , respectively. The Fe3O4@SiO2-LNS adsorbent can be recycled due to its good magnetism and the regeneration efficiency is over 85% after three cycles. Therefore, the prepared magnetic lignin-based adsorbent is a lowcost, high-efficiency and reusable adsorbent for wastewater treatment.