pH-Dependent Degradation of Methylene Blue via Rational-Designed MnO2 Nanosheet-Decorated Diatomites

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• 作者：Yu Xin Zhang ; Xiao Dong Hao ; Fei Li ; Zeng Peng Diao ; Zao Yang Guo ; Jing Li
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：April 30, 2014
• 年：2014
• 卷：53
• 期：17
• 页码：6966-6977
• 全文大小：865K
• 年卷期：v.53,no.17(April 30, 2014)
• ISSN：1520-5045

文摘

Hierarchical MnO₂-modified diatomite (MnO₂-D) nanostructures are synthesized through a one-pot hydrothermal method. By adjusting the preparative parameters, the morphology and surface pore size distribution of MnO₂-D composites can be well-controlled. Their nanostructures are examined by focused-ion-beam scanning electron microscopy (FIB/SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The results show that birnessite-type MnO₂ nanosheets are observed to grow vertically on the internal and external surfaces of purified diatomite, thus building a hierarchical architecture. Furthermore, the degradation ability of MnO₂-D composites toward MB solution is fully investigated. It was found that MnO₂-D composite degraded 97.7% of MB solution (0.02 g L^鈥?, 100 mL) by oxidation within only 5 min in acid solution (pH 2); moreover, in neutral solution (pH 6鈥?), this composite catalyzed the oxidation decomposition reaction of MB (0.02 g L^鈥?, 100 mL) by H₂O₂ with a high removal percentage of 92.4% in 2 h, and it also represented a high adsorption capacity of 714.3 mg g^鈥? for the removal of MB in alkaline solution (pH 11), respectively. In principle, these MnO₂-D composites provided an appropriate way for the degradation of complex and various dye wastewater in practical applications.