Tunable assembly of porous three-dimensional graphene oxide-corn zein composites with strong mechanical properties for adsorption of rare earth elements

Three-dimensional (3D) graphene oxide (GO)-based porous composites with strong compressive mechanical properties were prepared by self-assembly of corn zein (CZ) and GO through a facile hydrothermal process, which were used for the adsorption of rare earth elements (REEs) from aqueous solutions. The adsorption equilibrium for REEs by GO-CZ composites could be achieved within 200 min. And the maximum adsorption capacities of GO-CZ(9:1) for yttrium (Y), lanthanum (La), erbium (Er), ytterbium (Yb) and neodymium (Nd) were 14.2, 17.29, 11.72, 10.08 and 9.68 mg g(-1), respectively. The relatively high desorption rate (85-95%) of 3D GO-CZ(9:1) composite represents a higher reproducibility. Moreover, the 3D GO-CZ composites obtained with a mass ratio of 3:1, 5:1 and 9:1 for GO and CZ could be compressed to 60% of their original volumes and gradually restored to their original morphologies under the corresponding stresses of 18, 16 and 11 KPa, respectively. The adsorption mechanism was also proposed. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.