▎ 摘　　要

To date, existing methods for graphene functionalization entail complex procedures, hence efficient and facile methods are desired. In this study, alkylamine functionalization on reduced graphene hydrogel (rGH) was achieved via a facile two-step method involving hydrothermal treatment of graphene oxide (GO) to rGH followed by the immersion/agitation treatment of the rGH in octylamine (OA), decylamine (DA) and dodecylamine (DDA). It was found that the interactions of the alkylamine occurred via the epoxy ring-opening and amidation. To emphasize the advantage of this method, the adsorption kinetics on methylene blue (MB) and bisphenol-A (BPA) was further accessed. Shorter alkyl chain alkylamine (OA & DA) functionalized rGHs showed improvement in their adsorption capacity due to the increase in the specific surface area of the hydrogels. The highest specific surface area was obtained for rGH-DA at 47.80 m(2)/g followed by rGH-OA (47.37 m(2)/g), rGH-DDA (42.00 m(2)/g) and rGH (27.29 m(2)/g). However, longer chain alkyl chain alkylamine (DDA) functionalized rGHs showed lower adsorption capacity posited from the crowding of long alkyl chain which decreases the pi-pi interactions between the MB/BPA and the graphene sheets. rGH-DA exhibited the highest adsorption capacity for MB and BPA at 482 and 228 mg/g, respectively. In addition, the alkylamine functionalized hydrogels showed high regeneration behaviour after three cycles of adsorption-desorption: above 85% and 75% for MB and BPA, respectively. This proposed facile functionalization route will open interesting possibilities in the design of novel reduced graphene-based based hydrogels with improved adsorption performance that can bring ample benefits in wastewater remediation. (C) 2021 Elsevier B.V. All rights reserved.