Synthesis and Characterization of a Functionalized Graphene Oxide Hydrogel Nanocomposite for Efficient Lithium Ion Adsorption from Aqueous Solutions

In this study, a novel hydrogel-based nanocomposite was successfully synthesized by integrating polyvinyl alcohol (PVA) and graphene oxide (GO), aiming to develop an efficient, reusable adsorbent for lithium ion (Li⁺) removal from aqueous environments. Graphene oxide was synthesized using a modified Hummers’ method and incorporated into a hydrogel matrix to enhance surface area and provide functional groups for metal ion binding.The synthesized nanocomposite was structurally characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), which confirmed the successful formation of a porous, functionalized network with good structural stability and uniform dispersion of GO.Batch adsorption experiments were performed to investigate the effects of contact time, initial lithium concentration, solution pH, and temperature on adsorption performance. The kinetic data were best fitted to a pseudo-second-order model, indicating that chemisorption is the rate-limiting step. Isotherm studies revealed that the adsorption followed the Langmuir model, suggesting monolayer adsorption on a homogeneous surface. Thermodynamic parameters showed that the process was spontaneous and endothermic in nature.Moreover, the composite exhibited favorable reusability, maintaining high adsorption capacity over multiple adsorption–desorption cycles. These results highlight the potential of the PVA–GO hydrogel nanocomposite as a selective, efficient, and environmentally friendly material for lithium recovery from aqueous sources such as industrial brine, seawater, and battery wastewater. Its green synthesis, high performance, and reusability make it suitable for sustainable environmental remediation and resource recovery applications.