A general and programmable preparation of α-MnO2/GO/CS aerogels used for efficient degradation of MB in wastewater

Abstract

Heterogeneous Fenton reaction, as an efficient advanced oxidation process (AOP), has been proved as a promising method to treat organic wastewater. In this study, combining the outstanding adsorption capacity of aerogels and the excellent catalytic ability of α-MnO2, various composite aerogels functionalized by α-MnO2 through double cross-linking structures were developed to degrade methylene blue (MB) in a heterogeneous Fenton process. Herein, a series of α-MnO2/GO/CS composite aerogels with different amount of graphene oxide (GO) were prepared, and detailed characterizations were made to evaluate the structures of aerogels. Finally, aerogel-5 with the most amount of GO was proved to be the optimal catalyst, which could degrade 99.7 % MB in 50 min under an optimal condition (50 mL 30 mg/L MB, 0.05 g aerogels, 2 mL 30 % H2O2, pH = 10). Especially, aerogel-5 also displayed excellent degradation efficiency (D%) when used in higher concentration MB solution in 15 min (98.4 % for 100 mg/L MB, 98.1 % for 150 mg/L MB, 97.4 % for 200 mg/L MB). In addition, the D% still reached 92.7 % after the 5th reuse. Therefore, this work developed a high active composite catalyst, which would be promising for highly efficient treatment of dye wastewater.