Removal of methylene blue from water by graphene oxide aerogel: thermodynamic, kinetic, and equilibrium modeling

Existence of many functional groups on graphene oxide sheets offers potential applications for the removal of environmental pollutants such as heavy metals and dyes. Moreover, materials with aligned porosity in the micrometer range could further enhance the adsorption capability by providing more adsorption sites. In this paper, the performance of graphene oxide aerogel (GOA) prepared by ice segregation induced self-assembly method was investigated as an adsorbent to remove methylene blue (MB) from aqueous solutions. The adsorbent was characterized by XRD, FTIR, TEM, SEM, EDX, and BET. The results showed that GOA has extremely high adsorption capacity for removal of MB. The equilibrium of MB removal process by GOA was well described by the Langmuir isotherm model, with a maximum adsorption capacity of 416.6667 mg g(-1). The results of the thermodynamic investigations indicated that the adsorption reactions were spontaneous (Delta GA degrees A < 0), endothermic (Delta HA degrees A > 0) and the adsorption kinetics of MB on GOA was best fitted to the pseudo-second-order model.