Synthesis, characterization and study of arsenate adsorption from aqueous solution by {alpha}- and {delta}-phase manganese dioxide nanoadsorbents

Journal Article · Wed Dec 15 00:00:00 EST 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.09.023· OSTI ID:21494155

Singh, Mandeep ^[1]; Ulbrich, Pavel ^[2]; Strnadova, Nina ^[3]; Stepanek, Frantisek ^[1]

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1. Laboratory of Chemical Robotics, Department of Chemical Engineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic)
2. Department of Biochemistry and Microbiology, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic)
3. Department of Water Technology and Environmental Engineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6 (Czech Republic)

Single-phase {alpha}-MnO{sub 2} nanorods and {delta}-MnO{sub 2} nano-fiber clumps were synthesized using manganese pentahydrate in an aqueous solution. These nanomaterials were characterized using the Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Powder X-ray diffraction (XRD) and the Brunauer-Elmet-Teller nitrogen adsorption technique (BET-N{sub 2} adsorption). The structural analysis shows that {alpha}-MnO{sub 2} (2x2 tunnel structure) has the form of needle-shaped nanorods and {delta}-MnO{sub 2} (2D-layered structure) consists of fine needle-like fibers arranged in ball-like aggregates. Batch adsorption experiments were carried out to determine the effect of pH on adsorption kinetics and adsorption capacity for the removal of As(V) from aqueous solution onto these two types of nanoadsorbents. The adsorption capacity of As(V) was found to be highly pH dependent. The adsorption of As(V) onto {alpha}-MnO{sub 2} reached equilibrium more rapidly with higher adsorption capacity compared to {delta}-MnO{sub 2}. -- Graphical abstract: {alpha}-MnO{sub 2} (2x2 tunnel structure) nanorods and {delta}-MnO{sub 2} (2-D layered structure) nano-fiber clumps were synthesized in a facile way in an aqueous solution and characterized by TEM, FE-SEM, XRD and BET-N{sub 2} adsorption techniques. The structural analysis shows that {alpha}-MnO{sub 2} is needle shaped nanorods and {delta}-MnO{sub 2} consists of 2-D platelets of fine needle-like fibers arranged in ball-like aggregates. Further batch experiments confirmed that both nanoadsorbents are potential candidates for the adsorption of As(V) with a capacity of 19.41 and 15.33 mg g{sup -1} for {alpha}-MnO{sub 2} and {delta}-MnO{sub 2}, respectively. The presence of As3d peak in XPS study indicates that arsenic on the surface of nanoadsorbents is in the stable form of As(V) with a percentage of arsenate onto {alpha}-MnO{sub 2} is 0.099% as compared to 0.021% onto {delta}-MnO{sub 2}, clearly indicating the higher adsorption of As(V) in case of {alpha}-MnO{sub 2} as compared to {delta}-MnO{sub 2}, which is in good agreement with the adsorption studies results. Display Omitted

• OSTI ID: 21494155
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 12; Other Information: DOI: 10.1016/j.jssc.2010.09.023; PII: S0022-4596(10)00422-6; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ADSORPTION
ADSORPTION ISOTHERMS
AQUEOUS SOLUTIONS
ARSENATES
ARSENIC
KINETICS
MANGANESE OXIDES
NANOSTRUCTURES
NITROGEN
SCANNING ELECTRON MICROSCOPY
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
WATER TREATMENT
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY
ARSENIC COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
HOMOGENEOUS MIXTURES
ISOTHERMS
MANGANESE COMPOUNDS
MICROSCOPY
MIXTURES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SCATTERING
SEMIMETALS
SOLUTIONS
SORPTION
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS