Organosolv lignin/Fe3O4 nanoparticles applied as a β-glucosidase immobilization support and adsorbent for textile dye removal

In this paper, the liquor obtained from organosolv pretreatment of green coconut fiber (GCF) was used for the synthesis of lignin/Fe3O4 nanoparticles. The coating of Fe3O4 nanoparticles was evaluated by X-ray and dynamic light scattering analysis. β-glucosidase immobilized on lignin/Fe3O4 nanoparticles by covalent bonding exhibited better stability than free enzyme. Compared to the free enzyme, β-glucosidase immobilized on lignin/Fe3O4 nanoparticles achieved good digestibility performance of crystalline cellulose (∼ 21.9 g/L reducing sugars) and delignified GCF (∼ 6.4 g/L reducing sugars). In adsorption experiments, lignin/Fe3O4 nanoparticles exhibited low equilibration time and high adsorption capacity of Methylene blue (203.66 mg/g), Cibacron blue (112.36 mg/g) and Remazol red (96.46 mg/g) dyes. After four cycles, the adsorption of the Methylene blue dye on lignin/Fe3O4 nanoparticles reduced 43.68 % using 0.1 M HCl as eluent.