Kinetic Study of the Adsorption of Synthetic Dyes on Graphene Surfaces

Graphene (G) and Graphene oxide (GO) were employed in the present study in the removal of two toxic cationic dyes, Basic Red 12 (BR 12) and Basic Red 46 (BR 46), from aqueous solutions. Graphene oxide was synthesized according to the modified Hummers' method, and characterized by XRD and FTIR. The effect of various parameters such as contact time, solution pH, dye concentration and temperature, were studied. The kinetics and thermodynamics of the process of dye removal were investigated. The results indicate that the kinetics of the removal of BR 12 and BR 46 using G and GO as adsorbents follows a pseudosecond order model. G and GO exhibited high adsorption capacity for BR 12 and BR 46. The dye removal depends thereby on the initial pH of the solution with maximum uptake occurring at about pH=9.