MnO2 aerogels for highly efficient oxidative degradation of Rhodamine B

Abstract

High-efficiency oxidative degradation of Rhodamine B (RhB) is demonstrated with manganese dioxide (MnO₂) aerogels. The MnO₂ aerogels are fabricated by an ice-templating approach from MnO₂ nanosheet colloids, which have been synthesized by redox reaction between MnCl₂ and KMnO₄ in sodium dodecyl sulfate (SDS) aqueous solution. The obtained self-standing MnO₂ aerogels show a three dimensional (3D) structure of a percolating network with open pores ranging from hundreds of nanometers to tens of micrometers. The oxidative degradation efficiency of MnO₂ aerogels is compared with ultrathin MnO₂ nanosheets and commercial MnO₂ powder, and the effects of concentration of MnO₂ aerogels as well as pH on the degradation efficiency are also investigated. Typically, the MnO₂ aerogels show an excellent oxidative degradation performance of RhB (97.6% removed within 10 min) in acidic solution (pH 2.5), which can be attributed to the large open pores and high surface areas of the aerogels. Furthermore, the MnO₂ aerogels also exhibit good capability in the degradation of methylene blue (MB) under acidic conditions. It is believed that MnO₂ aerogels hold great promise for future applications in organic pollutant removal with virtues of high efficiency, low cost and environmental friendliness.