Preparation and characterization of spherical lignocellulose-based anion exchanger from sugarcane bagasse

Abstract

Biosorption is considered a promising technique for removing heavy metals from water. However, a biosorbent is usually prepared in the form of biomass powder that has drawbacks in stability and uniformity. Herein, a spherical lignocellulose-based anion exchanger (LCB-AE) was prepared from sugarcane bagasse through the method of dissolution-regeneration of biomass followed by quaternary ammonium modification. Dissolution-regeneration conditions of raw biomass were optimized, and the prepared materials were characterized by element composition analysis, pore-structure analysis (mercury intrusion porosimetry), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and carbon-13 nuclear magnetic resonance (13C-NMR) analyses. The LCB-AE has a macro-porous structure and a rough surface occupied mainly by quaternary ammonium and hydroxyl groups. Adsorption selectivity of LCB-AE follows the order of CrO42- > PO43- > SO42- > NO3-, and adsorption isotherms agree well with the Langmuir model, which suggests the experimental exchange abilities are approximately 0.8 to 0.9 mEq/g. These results show that LCB-AE as a new spherical biosorbent has the potential to be used for anions removal from water.