Activated Graphene Oxide for Removal of Methylene Blue from Aqueous Solutions

Activated graphene oxide (AGO) synthesized via the alkali activation of graphene oxide (GO) was evaluated for its efficacy in removing methylene blue (MB) from aqueous solutions. AGO samples were prepared with varying activation times $(0.5 \mathrm{~h}, 1.0 \mathrm{~h}, 1.5 \mathrm{~h})$ and characterized using SEM and FTIR analysis. The AGO-1.0 sample showed a highly exfoliated structure and the highest degree of reduction. The synthesized AGO was used as an adsorbent for MB removal from aqueous solutions. Adsorption studies revealed that the AGO-1.0 sample to have the highest removal efficiency and adsorption capacity (123.45 mg/g), attributed to its mesoporous and microporous structure. The adsorption behavior was analyzed using both Freundlich and Langmuir isotherm models, with the Langmuir model providing the better fit. Further, decreasing temperature results in an increase of adsorption capacity, indicating an exothermic nature of the adsorption process. These findings emphasize the potential of economically viable AGO as an effective adsorbent for the removal of cationic dyes from wastewater systems.