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

Abstract

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.