Magnetite Reduced Graphene Oxide/Ordered Mesoporous Carbon Nanocomposite as Effective Adsorbent for Removal of 2-Naphthol in Wastewater

Background: The wastewater released from various industries contains substantial amounts of organic compounds such as dyes and naphthols. However, naphthols are toxic to the environment and human health. So, it is essential to eliminate them, which will contribute to manufacturing and environmental management. Methods: In the work, an eco-friendly method is adapted to synthesize reduced graphene oxide (rGO) using Equisetum arvense plant extract as a strong reducing and stabilizing agent. Then, a hybrid nano adsorbent based on rGO and ordered mesoporous carbon (CMK-3) decorated with iron oxide nanoparticles (Fe3O4@rGO/CMK-3) was prepared as an adsorbent. We investigate the performance of Fe3O4@rGO/CMK-3 to remove 2-naphthol (2-NP). Results: The FE-SEM images exhibited spherical magnetite nanoparticles with sizes ranging from 31 to 47 nm on composite. Efficient removal (90%) of 2-NP from aqueous solution is demonstrated using high surface area Fe3O4@rGO/CMK-3 (initial concentration of 2-NP: 10 mg mL-1, pH: 5.0, time: 30 min, and amount of adsorbent dosage: 3 mg mL-1). The high surface area of Fe3O4@rGO/CMK-3, hydrogen binding, π-π stacking interaction between the benzene rings of 2-NP and graphitic skeleton of hybrid adsorbent facilitate the adsorption of 2-NP on the Fe3O4@rGO/CMK-3. The 2NP removal capacity by Fe3O4@rGO/CMK-3 showed a significant decrease during five successive cycles. Conclusions: These results promise the potential of high surface area Fe3O4@rGO/CMK-3 for efficient removal of 2-NP for wastewater treatment.