Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto graphene

Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26 mg/g at the conditions of initial phenol concentration of 50 mg/L, pH 6.3 and 285 K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous.

The effect of temperature on phenol adsorbed by graphene shows that the equilibrium adsorption capacity of phenol increases with the increase in temperature from 285 to 333 K. Increasing adsorption capacities with temperature indicates that the adsorption of phenol is controlled by an endothermic reaction.Figure optionsDownload as PowerPoint slideHighlights
► The graphene has high phenol adsorption capacity.
► The graphene has a high specific surface area of 305 m2/g.
► The adsorption capacity is high at acidic pH range.
► The graphene has rapid phenol adsorption rate.
► Phenol adsorption is a spontaneous and endothermic process.