Aminosugar-Functionalized Microspheres with Superior Boron Selectivity and Reusability: Synthesis, Performance, and Chelation Mechanism

Abstract

Traditional adsorbents often face challenges such as low adsorption capacity, poor selectivity, difficulties in regeneration, and limited stability, rendering them inadequate for boron-containing wastewater treatment. In this study, glycerol methacrylate (GMA) is graft-copolymerized with divinylbenzene (DVB) using radical polymerization (RP) and modified with gluconic acid δ-lactone (GDL) to synthesize a P(GMA-g-DVB) (PGD-D) microsphere adsorbent containing glucosamine groups. Characterizations including SEM, FTIR, BET, and TGA confirm abundant polyhydroxy saccharide structures and quaternary ammonium moieties distributed on the material surface, which facilitate boron capture. Batch adsorption experiments demonstrate that boron adsorption onto PGD-D conforms to the Langmuir isotherm and pseudo-second-order kinetic models, with a saturated adsorption capacity of 49.26 mg/g. After ten consecutive adsorption–desorption cycles, the adsorbent only loses 1.65 mg/g of its uptake capacity. Moreover, coexisting competitive cations and anions exert slight interference on boron removal. XPS characterization verifies that boron is mainly immobilized through chelation interactions. This work provides a straightforward synthetic route to fabricate a novel boron adsorbent with acceptable adsorption performance for boron separation from aqueous wastewater.