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

The MnO2 nanowires-deposited diatomite samples were prepared using the hydrothermal method with KMnO4 and (NH4)(2)S2O8. 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 degrees 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. (C) 2014 Elsevier Inc. All rights reserved.