N-doped and Se incorporated reduced graphene oxide nanocomposite as a new adsorbent for efficient Ni(II) ion removal from aqueous sample

In this study, nitrogen-doped and selenium-incorporated reduced graphene oxide nanocomposite (N-rGO/Se) was synthesized through a simple hydrothermal technique, and its potential for removing Ni (II) ions from water temperature was tested at room temperature. The synthesized nanocomposite was well-characterized using various techniques such as X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Raman, and dynamic light scattering (DLS). The N-rGO/Se (G4) nanocomposite exhibits higher adsorption capacity among various options ((G1 (GO), G2 (GO/Se), and G3 (rGO/Se)). The adsorption capacity of G1, G2, G3, and G4 was found to be 7.96, 12.26, 14.13, and 19.57 mmol/g, respectively. Moreover, kinetics studies show that the (G4) nanocomposite removed 100% of Ni²⁺ within 15–20 min. Mathematical models such as pseudo-first- and second-order kinetics, Langmuir, Freundlich, and Sips isotherm were used to predict the efficiency of the nanocomposites. The results indicate that N-rGO/Se (G4) nanocomposite is an efficient and convenient adsorbent for removing Ni²⁺ from aqueous solutions.