Characterization and bisphenol A adsorption capacity of β-cyclodextrin-carboxymethylcellulose-based hydrogels

Novel hydrogel beads having molecular adsorption abilities were prepared from carboxymethylcellulose sodium salt (CMC) and beta-cyclodextrin (beta-CD) by suspension crosslinking, using ethylene glycol diglycidyl ether (EGDE) in basic medium as a crosslinking agent. FTIR and solid-state NMR spectroscopic analysis revealed that the amount of incorporated beta-CD and crosslinking densities within the hydrogel bead structures are strongly dependent on the molar feed ratio of beta-CD to CMC during preparation. The hydrogel beads showed water-swelling capacities of 70-200 mL/g-polymer, with decreases in capacity associated with increased amounts of beta-CD incorporated in the gel structure. The hydrogel beads also showed a high adsorption capacity toward bisphenol A (BPA) in water. Batch BPA-adsorption experiments were analyzed employing Langmuir isotherm models; hydrogel bead adsorption isotherms for BPA could be fitted to the Langmuir model. The maximum BPA-adsorption among the prepared series of hydrogel beads amounted to 167 mu mol g(-1). (C) 2013 Elsevier Ltd. All rights reserved.