Studying the Adsorption Process of Cadmium Ions by Fe3O4/Lmethionine/ graphene Oxide and Graphene Aerogel Nanocomposites from Aqueous Environments

Background: In recent years, graphene oxide (GO) and its nanocomposites have shown effective performance in wastewater treatment. Moreover, graphene aerogels (GAs) have excellent properties, such as high surface area, high porosity, low density, high electrical conductivity, and good mechanical properties, due to the combination of three-dimensional porous structures and excellent properties of graphene. Methods: In this study, synthesis of Fe3O4/L-methionine and graphene oxide and graphene aerogel nanocomposites (Fe3O4/L-Met, Fe3O4/L-Met/GO, Fe3O4/L-Met/GA) was performed. Then, the synthesized nanocomposites were confirmed by FT-IR, SEM and BET analyses. The adsorption capacity of cadmium ion by methionine nanocomposites and the effect of various experimental parameters, such as contact time, initial metal ion concentration, and initial pH, on the adsorption process were investigated. Results: The results showed that Fe3O4/L-Met at pH 7 was suitable for Cd (II) removal with 90% removal efficiency. In addition, adsorption capacity experiments at a constant concentration of 50 ppm Cd²⁺ showed that more than 50% of Cd²⁺ ions could be adsorbed by Fe3O4/L-Met and reach equilibrium within 2 hours. Conclusion: Thus, Fe3O4/L-Met/GA showed high adsorption capacity towards Cd²⁺ (212.31 mg/g), which was significantly higher than Fe3O4/L-Met (201.23 mg/g). Finally, adsorption kinetics and isotherm studies were investigated. Adsorption data showed excellent fit with quasi-second order models (R²> 0.99) and Freundlich isotherm models.