Effect of the degree of oxidation of graphene oxide on As(III) adsorption

• Published in: Journal of hazardous materials 2020-02, Vol.384, p.121440-121440, Article 121440
• Main Authors: Reynosa-Martínez, A.C., Tovar, G. Navarro, Gallegos, W.R., Rodríguez-Meléndez, H., Torres-Cadena, R., Mondragón-Solórzano, G., Barroso-Flores, J., Alvarez-Lemus, M.A., Montalvo, V. García, López-Honorato, E.
• Format: Article
• Language: English
• Subjects: Adsorption capacity; Arsenic; Oxidation degree; Oxygenated functional groups
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121440

[Display omitted] •Three types of graphene oxide were produced with different degree of oxidation.•Structural and compositional changes affect graphene oxide-As(III) adsorption.•A higher As(III) adsorption capacity is reached with a higher degree of oxidation.•Interaction energies of graphene oxide-arsenic were calculated by computer modeling.•The cytotoxicity of graphene oxide is not dependent on its degree of oxidation. The study of the interaction between graphene oxide (GO) and arsenic is of great relevance not only in the design of adsorbent materials to remove this contaminant but also in the understanding of its combined nanotoxicity. In this work, we show that As(III) adsorption, primarily H3AsO3, by graphene oxide is affected by its degree of oxidation. Three types of GO with C/O ratios between 1.35 and 1.98 were produced, resulting in important variations in the concentration of COH and COC functional groups. The less oxidized material reached a maximum As(III) adsorption capacity of 123 mg/g, whereas the GO with the highest degree of oxidation reached a value of 288 mg/g at pH 7, the highest reported in the literature. We also show that sulfates and carbonates present in water strongly inhibit As(III) adsorption. The interaction between graphene oxide and As(III) was also studied by Density Functional Theory (DFT) computer models showing that graphene oxide interacts with As(III) primarily through hydrogen bonds, having interaction energies with the hydroxyl and epoxide groups of 1508.6 and 1583.6 kJ/mol, respectively. Finally, cytotoxicity tests showed that the graphene oxide maintained cellular viability of 57% with 50 μg/ml, regardless of its degree of oxidation.