The Adsorption of Methylene Blue on Eco-Friendly Reduced Graphene Oxide

• Published in: Nanomaterials (Basel, Switzerland) Vol. 10; no. 4; p. 681
• Main Authors: Arias Arias, Fabian, Guevara, Marco, Tene, Talia, Angamarca, Paola, Molina, Raul, Valarezo, Andrea, Salguero, Orlando, Vacacela Gomez, Cristian, Arias, Melvin, Caputi, Lorenzo S
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04-04-2020; MDPI
• Subjects: Adsorption; Cationic dyes; Chemisorption; citric acid; Dyes; Efficiency; Electrostatic properties; Factorial experiments; Graphene; Graphite; Isotherms; Kinetics; Membrane separation; Methylene blue; Nanomaterials; Pollutants; Purification; reduced graphene oxide; Spectrum analysis; Textile industry; Wastewater treatment; Water purification; United States > US; Japan; citric acid; methylene blue; adsorption; reduced graphene oxide
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10040681

Recently, green-prepared oxidized graphenes have attracted huge interest in water purification and wastewater treatment. Herein, reduced graphene oxide (rGO) was prepared by a scalable and eco-friendly method, and its potential use for the removal of methylene blue (MB) from water systems, was explored. The present work includes the green protocol to produce rGO and respective spectroscopical and morphological characterizations, as well as several kinetics, isotherms, and thermodynamic analyses to successfully demonstrate the adsorption of MB. The pseudo-second-order model was appropriated to describe the adsorption kinetics of MB onto rGO, suggesting an equilibrium time of 30 min. Otherwise, the Langmuir model was more suitable to describe the adsorption isotherms, indicating a maximum adsorption capacity of 121.95 mg g
at 298 K. In addition, kinetics and thermodynamic analyses demonstrated that the adsorption of MB onto rGO can be treated as a mixed physisorption-chemisorption process described by H-bonding, electrostatic, and π - π interactions. These results show the potential of green-prepared rGO to remove cationic dyes from wastewater systems.