Adsorption of Gadolinium (Gd3+) Ions on the Dibenzo Crown Ether (DBCE) and Dicyclo Hexano Crown Ether (DCHCE) Grafted on the Polystyrene Surface: Insights from All Atom Molecular Dynamics Simulations and Experiments

Abstract

All atom molecular dynamics simulations and experiments were performed to understand the adsorption behavior of gadolinium (Gd3+) ion on the crown ethers grafted polystyrene (PS) surface. Two different types of crown ethers, viz., dibenzo crown ether (DBCE) and dicyclo hexano crown ether (DCHCE), were grafted separately on the PS surface to understand the adsorption behavior. We investigate the roles of Gd3+ ion concentration and grafting density (ρs) of the crown ether on the adsorption behavior of Gd3+ ion on the PS surface. The adsorption of Gd3+shows an increasing trend with increasing salt concentration, for all cases of crown ether grafting densities. The adsorption behavior follows the Langmuir isotherm model. The maximum amount of Gd3+ ion adsorption was observed to be 1.83 mg/g for DBCE and 2.02 mg/g for DCHCE at ρs = 2.07 mol/nm2. The maximum amount of Gd3+ ion adsorption on DBCE coated PS beads, in batch experiments, was found to be 1.76 mg/g, which is in good agreement with the theoretical res...