N-doped reduced graphene oxide aerogel for the selective adsorption of oil pollutants from water: Isotherm and kinetic study

Abstract

N-doped graphene aerogel with a 3D inter-connected network was synthesized using graphene oxide and pyrrole in an aqueous medium with ammonia. Hydrothermal and thermal annealing methods were employed to do it so. The structure and surface properties of the synthesized aerogel were characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), XPS, and nitrogen adsorption/desorption measurements. The prepared n-doped aerogel exhibited elevated specific surface area (340m2/g), hydrophobic nature, and excellent adsorption capacity (210g/g for crude oil removal). Adsorbent recyclability was also investigated; it is worth noting that after ten subsequent cycles, only just a negligible decrement in adsorption capacity was observed. Furthermore, the effect of salts and temperature on adsorption capacity was studied. Isotherm and kinetic studies were last examined. The conformity of various adsorption models, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D–R) to the equilibrium data was evaluated among which Langmuir isotherm model gave the best fitting result. The sorption kinetics data were well described by the pseudo-second-order kinetic model. As a consequence, oil spills adsorption using n-doped graphene aerogel is a relatively cost-effective method which can be scaled up, and it could be a promising material for removal of organic contaminants from water.