A novel 3D adsorbent of reduced graphene oxide-Β-cyclodextrin aerogel coupled hardness with softness for efficient removal of bisphenol A

A novel three-dimensional (3D)adsorbent of reduced graphene oxide-β-cyclodextrin (r-GO-CD)aerogel was firstly synthesized through a one-step hydrothermal reaction. Various physicochemical characterization results demonstrated that the cross-linking of “soft” β-cyclodextrin among the “hard” graphene oxide nanosheets, simultaneously combining with self-assembly process of aerogel, contributed to the formation of superior structural and stable r-GO-CD aerogel. The adsorption of bisphenol A (BPA)onto r-GO-CD was chemisorption and endothermic, which fitted well with the pseudo-second-order kinetic and Langmuir isotherm. The saturated adsorption capacity of r-GO-CD towards BPA was 346.0 mg g⁻¹ at 298 K, which was ∼11 times to that of conventional activated carbon. The r-GO-CD displayed a promising environmental application potential as revealed from the stable BPA adsorption efficiency in diverse interferences (H⁺/OH⁻, NaCl), presence of trace BPA and repeated cycling tests. The long-term dynamic filtration experiment conducted with raw surface water showed that the effective treated volume of r-GO-CD towards BPA (100 μg L⁻¹)was 270 mL which was ∼30 times to that of r-GO due to the excellent selectivity and adsorptivity of β-cyclodextrin for BPA. The distinct adsorption mechanism of r-GO-CD aerogel was demonstrated as synergistic effects of graphene oxide nanosheets and β-cyclodextrin, along with π-π interaction and hydrogen bonding.