The Effect of Support on the Catalytic Efficiency of MnO₂/Activated Carbon for degradation of Methylene blue

Abstract

Methylene blue (MB) is a blue cationic thiazine dye which is widely used in cotton fiber, wood and textile industries, but has an adverse effect to environment and living organism. It is urgent to find an alternative and effective solution for this recalcitrant compound. The Fenton process-based advanced oxidation process is considered as an effective method for the degradation of organic contaminants such as dyes. In this study, the composite α-MnO2/activated carbon (AC) was first synthesized by a facile, one-pot synthesis using sol-gel method and characterized by X-ray diffraction (XRD) and BET surface areas. The XRD results indicated that the tunnel cryptomelane-type manganese oxide (α-MnO2) was successfully synthesized as the minor phase in the activated carbon support. The composite α-MnO2/AC has higher specific surface area than the single α-MnO2. The catalytic studies indicated that the α-MnO2/AC has a much higher catalytic efficiency over single α-MnO2 for degradation of MB. The presence of the support and the increase in surface area of α-MnO2/AC could be responsible for its higher catalytic efficiency compared to single α-MnO2. In the optimum condition, the α-MnO2/AC was able to degrade 98.48 % and 99.2 % of MB within 10 and 120 minute of reaction time, respectively.