Preparation of black-pearl reduced graphene oxide–sodium alginate hydrogel microspheres for adsorbing organic pollutants

Abstract The black-pearl reduced graphene oxide–sodium alginate (rGO–SA) hydrogel microspheres are prepared by the external emulsification and thermal reduction method, which are characterized by scanning electron microscope (SEM) and X-ray Diffraction (XRD). Sodium alginate (SA) serves as a template to form a 3D porous network structure, which can prevent the agglomeration and restacking of rGO sheets efficiently. The size of hydrogel microsphere can be controlled by adjusting the size of the liquid drop. The effects of rGO content (wt%), contact time, initial concentration of phenol, adsorption temperature and adsorption dose on the adsorption capacity of rGO–SA microspheres are investigated. The kinetics and isotherm data are well described by the pseudo-second-order kinetic model and the Langmuir equation, respectively. Thermodynamic results demonstrate the spontaneous and endothermic nature of adsorption. This rGO–SA microsphere exhibits the favorable adsorption performance for phenol, BPA and tetracycline. The rGO–SA microsphere might be a potential candidate for efficient adsorbents in water treatment.