Transformations of Synthetic Birnessite as Affected by pH and Manganese Concentration

Tu, Shuangshuang

doi:10.1346/ccmn.1994.0420310

Cited by 88 publications

(71 citation statements)

References 20 publications

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“…Partial dehydration of buserite leads to the formation of 7 Å birnessite with a single layer of H 2 O molecules and various interlayer cations Burns 1977, 1978;Chukhrov et al 1978Chukhrov et al , 1989Cornell and Giovanoli 1988). Buserite and birnessite have remarkable cation exchange (Healy et al 1966;Murray 1974;Balistrieri and Murray 1982;Stumm 1992;Le Goff et al 1996), sorption (Gray and Malati 1979;Catts and Langmuir 1986;Paterson et al 1994;Tu et al 1994;Appelo and Postma 1999), and redox properties (Oscarson et al 1983;Stone and Morgan 1984;Stone and Ulrich 1989;Manceau and Charlet 1992;Bidoglio et al 1993;Silvester et al 1995;Manceau et al 1997;Pizzigallo et al 1998;Daus et al 2000;Nico and Zasoski 2000;Chorover and Amistadi 2001).…”

Section: Introductionmentioning

confidence: 99%

Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Lanson

Drits

Gaillot

et al. 2002

American Mineralogist

124

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The structure of heavy-metal sorbed synthetic birnessites (MeBi) was studied by powder X-ray diffraction (XRD) using a trial-and-error fitting procedure to improve our understanding of the interactions between buserite/birnessite and environmentally important heavy metals (Me) including Pb, Cd, and Zn. MeBi samples were prepared at different surface coverages by equilibrating at pH 4 a Na-rich buserite (NaBu) suspension in the presence of the desired aqueous metal.

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Section: Introductionmentioning

confidence: 99%

Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Lanson

Drits

Gaillot

et al. 2002

American Mineralogist

124

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“…The remaining unoxidized Co 2+ is adsorbed above or below the vacant sites . As Mn 2+ is easily oxidized by birnessite (Tu et al 1994) and as the radius of Mn 3+ (0.066 nm) is close to that of Co 3+ (0.063 nm; Pauling 1960), it is reasonable to suggest that the oxidation of Mn 2+ to Mn 3+ on birnessite is similar to the oxidation of Co 2+ adsorbed on buserite. Therefore, the first and third mechanisms are both possible.…”

Section: Discussionmentioning

confidence: 99%

“…Mn 2+ can be oxidized to Mn 3+ by birnessite (Tu et al 1994), and the radius of Mn 3+ (0.066 nm) is close to that of Co 3+ (0.063 nm; Pauling 1960), suggesting that the oxidation of Mn 2+ to Mn 3+ on birnessite is similar to that of Co 2+ oxidation to Co 3+ on buserite, leading to a decrease in vacant Mn sites in birnessite.…”

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confidence: 91%

“…The interlayer water molecules and cations that compensate the charges created by defects in the Mn octahedral layers have a profound influence on the resulting structure (Webb et al 2005). Many Mn oxides can be synthesized by direct or indirect transformation of birnessite (Golden et al 1987;Tu et al 1994). Birnessite synthesis can be achieved by the reduction of potassium permanganate in a strong acidic medium (McKenzie 1971), which is termed "acid-birnessite" (Villalobos et al 2003).…”

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confidence: 99%

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Pb2+ adsorption on birnessite affected by Zn2+ and Mn2+ pretreatments

et al. 2010

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Purpose Lead contamination is ubiquitous, and much attention has been paid due to its toxicity. The phyllomanganate birnessite is the most common Mn oxide in soils. The MnO 6 octahedral layers may have significant Mn vacancies in the hexagonal birnessites. Among heavy metal ions, birnessites possess the greatest adsorption affinity and capacity for Pb 2+ . The aim of this study was to understand the relationship between vacant Mn octahedral sites and Pb 2+ adsorption. Materials and methods Birnessite synthesis was achieved by the reduction of potassium permanganate in a strong acidic medium. Synthetic birnessite was then treated with Mn 2+ or Zn 2+ at different concentrations. Isothermal Pb 2+ adsorption on birnessite before and after treatments was measured at a solid-to-liquid ratio of approximately 1.67 g/L, and Pb 2+ concentrations ranged from 0 to 10 mmol/L with an ionic strength of 0.1 mol/L NaNO 3 . The amount of Pb 2+ adsorbed and the amount of Mn 2+ or Zn 2+ released during the whole adsorption process were obtained by comparison with a control group without adding Pb 2+ . The amount of H + released was determined from the recorded additions of standard HNO 3 /NaOH solutions. Results and discussion Mn average oxidation state (AOS) and d(110)-interplanar spacings of the birnessites remained almost unchanged as the concentration of the treating Zn 2+ increased, indicating an unchanged number of vacant Mn octahedral sites, whereas the maximum Pb 2+ adsorption decreased from 3,190 to 2,030 mmol/kg due to the presence of Zn 2+ on adsorption sites. The AOS's of the Mn 2+ -treated birnessites decreased and most of the Mn 2+ ions added were oxidized to Mn 3+ ions. The d(110)-interplanar spacing of Mn 2+ -treated birnessites increased from 0.14160 to 0.14196 nm, indicative of a decreased vacant Mn octahedral sites. Moreover, the maximum Pb 2+ adsorption of Mn 2+ -treated birnessites decreased from 3,190 to 1,332 mmol/kg, the decrease being greater than that for the corresponding Zn 2+ -treated birnessites. Conclusions Most Mn 2+ was oxidized to Mn 3+ by birnessite, with a portion of Mn 3+ located above or below vacant sites, which did not affect the number of vacant sites, and the remaining Mn 3+ migrating to occupy the vacant sites. In contrast, Zn 2+ ions are adsorbed only above or below vacant sites. Birnessite Pb 2+ adsorption capacity is determined largely by the number of vacant Mn sites.

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“…R-MnO 2 was formed with transformation of birnessite after adsorbing Mn 2＋ at pH 2.4, but XRD results identified that the product was a mixture of nsutite and ramsdellite. 17 Rietveld refinement technique and oriented single-crystal IR absorption spectra were used to characterize the ramsdellite, which was found to be easily distorted to groutite, α-MnOOH. 18,19 Rossouw et al prepared pure R-MnO 2 with digestion of spinel LiMn 2 O 4 or Li 2 Mn 4 O 9 in moderately concentrated sulfuric acid solution at 95 ℃ for 24 h. However, the preparation process was multistep, complicated and timeconsuming.…”

Section: Introductionmentioning

confidence: 99%

Shape‐controlled Synthesis of Nanostructure Ramsdellite‐type Manganese Oxide at Atmospheric Pressure

Qiu¹,

Wang²,

Zhao³

et al. 2010

Chin. J. Chem.

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Ramsdellite (R-MnO 2 ) was prepared by oxidizing bivalent manganese salts, such as MnCl 2 , MnSO 4 and Mn(NO 3 ) 2 , with NaClO solution using a refluxing process at atmospheric pressure. The products were characterized by X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and flame photometry. R-MnO 2 microstructure and morphology were controlled by adjusting reaction temperature, the amount of hydrochloric acid (HCl) and anions of bivalent manganese salts. Ramsdellite grain was formed with three different bivalent manganese salts oxidized by NaClO solution at 60 ℃, and increased with the increase of reflux temperature. R-MnO 2 nanorod and nanowire crystals were obtained when MnCl 2 and MnSO 4 were used as bivalent manganese salts at 100 ℃ respectively. Nanosized flake of R-MnO 2 came into being when Mn(NO 3 ) 2 was applied at 80 ℃. When 30 mmol MnCl 2 was oxidized by 60 mmol NaClO solution with adding 20 mmol HCl in refluxing solution, specific surface area of R-MnO 2 grain obtained at 60 ℃ was greater than 140 m 2 /g, and the self-assembly of nanorod bundles into interesting flowerlike architectures was achieved at 100 ℃.The process of dissolution-precipitation equilibrium might be the primary cause for the morphology transformation.

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Transformations of Synthetic Birnessite as Affected by pH and Manganese Concentration

Cited by 88 publications

References 20 publications

Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Pb2+ adsorption on birnessite affected by Zn2+ and Mn2+ pretreatments

Shape‐controlled Synthesis of Nanostructure Ramsdellite‐type Manganese Oxide at Atmospheric Pressure

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