Facile synthesis of reduced-graphene-oxide/rare-earth-metal-oxide aerogels as a highly efficient adsorbent for Rhodamine-B

The multifunctional reduced-graphene-oxide/rare-earth-metal-oxide (RGO/REMO) aerogels with three-dimensional (3D) interconnected networks were fabricated through a facile one-step hydrothermal method and freeze-drying process. It was proved that REMO nanoparticles could be easily deposited on graphene sheets in gentle conditions. To further investigate the effect of REMO on the adsorption of dyes, RGO/Nd2O3, RGO/Pr2O3 and RGO/Ce2O3 aerogels were used to adsorb the Rhodamine-B (RhB). The RGO/REMO aerogels all exhibited high adsorption capacity for RhB and the maximal adsorption capacity was as high as 243.4 mg.g(-1). In particular, RGO/Ce2O3 aerogel had a significant adsorption efficiency for RhB, and the adsorption capacity of RGO/Ce2O3 aerogel for RhB reached 130.1 mg.g(-1) only in one hour. Furthermore, as for RGO/Ce2O3 aerogel, the removalrate of RhB was still more than 92% after nine repeated regeneration. The excellent adsorption capacity and high repeated utilization rate of RGO/REMO aerogels indicated that the composite adsorbent possessed potential practical application in the treatment of wastewater containing RhB.