MnO2 nanowires in situ grown on diatomite: Highly efficient absorbents for the removal of Cr(VI) and As(V)

• MnO2 nanowires are in situ grown on diatomite via the hydrothermal route.
• MnO2 nanowires/diatomite shows excellent performance for Cr(VI) or As(V) adsorption.
• Maximal Cr(VI) and As(V) adsorption capacities are 197.6 and 108.2 mg/g, respectively.
• Maximal Cr(VI) and As(V) removal efficiency is 100% and 99.9%, respectively.

The MnO2 nanowires-deposited diatomite samples were prepared using the hydrothermal method with KMnO4 and (NH4)2S2O8. Physicochemical properties of the samples were characterized by means of numerous techniques, and their efficiency for the removal of Cr(VI) and As(V) was determined. The parameters, such as pH value, adsorption time, adsorbent mass, and initial Cr(VI) or As(V) concentration, could influence the Cr(VI) and As(V) removal efficiency or adsorption capacity of the MnO2 nanowires/diatomite sample obtained after hydrothermal treatment at 90 °C for 12 h. These MnO2 nanowires/diatomite samples showed high surface areas and superb Cr(VI) and As(V) adsorption behaviors, with the maximum Cr(VI) and As(V) adsorption capacities being 197.6 and 108.2 mg/g, respectively. The Cr(VI) and As(V) adsorption mechanisms of the samples were also discussed.

The ordered MnO2/diatomite in situ grown on diatomite samples are prepared via a hydrothermal route. It is found that the MnO2 nanowires/diatomite sample obtained after hydrothermal treatment for 12 h shows the maximal Cr(VI) and As(V) adsorption capacities of 197.6 and 108.2 mg/g, respectively.Figure optionsDownload as PowerPoint slide