Graphene oxide/chitosan/potassium copper hexacyanoferrate(II) composite aerogel for efficient removal of cesium

Efficient removal of 137Cs from various radioactive wastewater and contaminated environment is much meaningful for nuclear energy sustainable development and public health. Herein we used chitosan (CS) to induce the self-assembly of graphene oxide (GO) into a hydrogel (GO/CS) possessing a three-dimensional macroporous structure and produced a type of ternary composite hydrogel/aerogel named GO/CS/Cu-PBA by in situ growing potassium copper hexacyanoferrate(II) (Cu-PBA) nanoparticles onto the GO/CS via simple leaching. The adsorption behaviors of Cs+ by GO, Cu-PBA, and GO/CS/Cu-PBA in various matrice was systematically studied and compared. It was found that the GO/CS/Cu-PBA exhibited satisfactory sorption capacity for Cs+ (64.7 mg/g) and ultrafast kinetics. In addition, a fixed-bed column system could be employed for the cleanup of Cs+ from contaminated groundwater. Further FT-IR, XRD, XPS, and EXAFS analyses clarified the interaction mechanism between Cs+ and GO/CS/Cu-PBA. Highly selective fixation of Cs+ by Cu-PBA was accompanied by the release of K+/Cu2+ and a crystalline phase transition. The adsorption of Cs+ by GO was mainly correlated with the electrostatic attraction by –COO− and C-OH groups. The confinement of Cu-PBA by GO/CS aerogel is of much potential for the practical treatment of cesium-containing radioactive wastewater.