Adsorption of nitrate from water by core-shell chitosan wrinkled microspheres @LDH composite: Electrostatic interaction, hydrogen bonding and surface complexation

Over the years, nitrate pollution has always been one of the key issues of global concern. In this study, a new core-shell composite (GCS@LDH) was prepared by in-situ growth of MgAl layered double hydroxide (MgAl LDH) plates on the wrinkled surface of crosslinked chitosan (CS) microsphere (GCS), which applied for nitrate removal. The wrinkles and LDH plates of GCS surface provide a larger specific surface area, which can avoid the aggregation of LDH and conducive to adsorption. The hydroxyl groups and metal hydroxide of LDH and numerous active groups of GCS improved the adsorption effect by synergistic effect. The GCS@LDH were synthesized successfully proved by various characterization analyses. In addition, the adsorption mechanism of nitrate on GCS@LDH were investigated and confirmed by experiment and characterization analysis. The adsorption kinetics, isotherm, thermodynamics and reusability of GCS@LDH were also discussed. This paper aims to provide a new core-shell chitosan microspheres @LDH adsorbent for nitrate adsorption.