Methylene Blue Adsorption by Plasma Re-Activated Carbon

The effects of O2 plasma treatment on the adsorption capacity of activated carbon (AC) were investigated by varying the plasma treatment times. The surface properties of the AC were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Zeta potential. The carbon was then applied to remove methylene blue (MB). The adsorption kinetics and isotherm were also studied. Results showed that pseudo-second-order kinetics was the most suitable model for describing the adsorption of MB onto AC. Equilibrium data were well fitted to the Freundlich isotherm model. The highest adsorption capacity resulted from 4 minutes of O2 plasma treatment. The 4-minute plasma treated AC had the best adsorption capacity for MB at 0.467 mg/mg. This work shows that activation of AC by plasma can open the micropore and increase the effectiveness of chemical removal.