Crystallochemical characterization of magnetic spinels prepared from aqueous solution

Mann, Stephen; Sparks, Nicholas; Couling, Suzanne B.; Larcombe, Miranda C.; Frankel, Richard B.

doi:10.1039/f19898503033

Cited by 59 publications

(65 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, this material may provide a source for finely divided maghemites in nature, independent of magnetite oxidation. At Fe(II)/Fe(III) -< 0.5, ferrihydrite converts to spinel without green rust intermediates, contrary to what is observed at higher Fe(II) levels (Mann et al, 1989).…”

Section: Discussioncontrasting

confidence: 43%

“…Divalent transition metal cations (M = Fe, Mn, Cu, Ni, Co, Zn) at sufficiently high ratios (M(II)/Fe(III) > 0.2, roughly) are known to interact with the least ordered variety of ferrihydrite to produce phases with the spinel structure (Cornell andGiovanoli, 1987, 1988;Cornell, 1988;Mann et al, 1989). This generally proceeds by dissolution and reprecipitation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Fe(II) on the Formation of the Spinel Iron Oxide in Alkaline Medium

Jolivet

Belleville

Tronc

et al. 1992

Clays and clay miner.

132

View full text Add to dashboard Cite

Fe(II) and Fe(III) in various proportions were coprecipitated by NH3 at pH ≈ 11. The Fe(II)/Fe(III) ratio (x) was varied from 0.10 to 0.50. After stabilization by aging at pH ≃ 8 in anaerobic conditions, hydrous precipitates were characterized by electron microscopy, Mössbauer spectroscopy, and kinetics of dissolution in acidic medium. At any x value, all stable products exhibited the structure of (oxidized) magnetite. For x ≤ 0.30, two distinct species were coexisting: the one (“m”) was made up of ca. 4nm-sized particles with a low Fe(II) content (Fe(II)/Fe(III) ≈ 0.07), and the other (“M”) consisted of particles of larger, more or less distributed sizes, and composition Fe(II)/Fe(III) ≈ 0.33; “M” increased relative amount with increasing x. For x ≥ 0.35, “M” was the only constituent and its Fe(II)/Fe(III) ratio was equal to x. “M” is identified with (nonstoichiometric) magnetite, whereas “m” is likely to be an oxyhydroxide. Mechanisms of formation are discussed, and a phase diagram is proposed which schematizes the evolution of the coprecipitation products with x and with time. Addition of Fe(II) after the precipitation of Fe(III), instead of coprecipitation, yielded very similar results.

show abstract

Section: Discussioncontrasting

confidence: 43%

Section: Introductionmentioning

confidence: 99%

Influence of Fe(II) on the Formation of the Spinel Iron Oxide in Alkaline Medium

Jolivet

Belleville

Tronc

et al. 1992

Clays and clay miner.

132

View full text Add to dashboard Cite

show abstract

“…This was not unexpected, given the minimal changes in bulk structure and surface chemistry imbued by vacuum annealing and a concurrent decrease in surface area (by 22.1%). [19][20][21]. A second minor peak centred at 11.8 ∘ 2 was also recorded for both nanomaterials, which is ascribed to akaganéite ( -FeOOH), with a lattice reflection of (110) [22].…”

Section: Changes In Aqueous Fe Concentrationmentioning

confidence: 92%

The Effect of Vacuum Annealing of Magnetite and Zero-Valent Iron Nanoparticles on the Removal of Aqueous Uranium

Crane

Scott

2013

Journal of Nanotechnology

View full text Add to dashboard Cite

As-formed and vacuum annealed zero-valent iron nanoparticles (nano-Fe 0 ) and magnetite nanoparticles (nano-Fe 3 O 4 ) were tested for the removal of uranium from carbonate-rich mine water. Nanoparticles were introduced to batch systems containing the mine water under oxygen conditions representative of near-surface waters, with a uranyl solution studied as a simple comparator system. Despite the vacuum annealed nano-Fe 0 having a 64.6% lower surface area than the standard nano-Fe 0 , similar U removal (>98%) was recorded during the initial stages of reaction with the mine water. In contrast, ≤15% U removal was recorded for the mine water treated with both as-formed and vacuum annealed nano-Fe 3 O 4 . Over extended reaction periods (>1 week), appreciable U rerelease was recorded for the mine water solutions treated using nano-Fe 0 , whilst the vacuum annealed material maintained U at <50 g L −1 until 4 weeks reaction. XPS analysis of reacted nanoparticulate solids confirmed the partial chemical reduction of U VI to U IV in both nano-Fe 0 water treatment systems, but with a greater amount of U IV detected on the vacuum annealed particles. Results suggest that vacuum annealing can enhance the aqueous reactivity of nano-Fe 0 and, for waters of complex chemistry, can improve the longevity of aqueous U removal.

show abstract

“…Unlike BOB-type magnetite. particles produced by GS-15 have shape and size distributions very similar to parti cles of inorganic magnetite precipitated at low temperatures from aqueous solutions or during soil formation [21,26,27]. Hence, crystal morphol ogy alone is not a useful criterion for identifying 81M-type magnetite.…”

Section: Introductionmentioning

confidence: 98%

“…With few exceptions, all BOB-type magnetites have crystal morphologies that are distinct from fine-grained magnetite of inorganic origin [e.g., 15, 26,27]. Morphological analysis of magnetite particles with HRTEM, therefore, provides one way of identifying biogenic magnetite (i.e., mag netosomes) in sediments [6,7].…”

Section: Introductionmentioning

confidence: 99%

Rock magnetic criteria for the detection of biogenic magnetite

Moskowitz

Frankel

Bazylinski

1993

Earth and Planetary Science Letters

Self Cite

421

519

View full text Add to dashboard Cite

We rcpmt results on the magnetic properties of magnetites produced by magnetotaetie and dissimilatory iron-reducing bacteria. Magnetotactic bacterial (MTB) strains MS I. MV J and MV2 and dissimilatory iron-reducing bacterium ,train GS-15. grown in pure cultures, were used in this study, Our results suggest that a comhination of room tempnature coercivity analysis and low temperature remanence measurements provides a characteristic magnetic signature for intact chains of single domain (SD) particles of magnetite from MTBs. The most useful magnetic property measurements include: (1) acquisition and demagnetization of isothermal remanent magnetiza tion (IRM) using static, pulse and altcrnating fields: (2) acquisition of anhysteretie remanent magnetization (ARM); and (3) thermal dependence of low temperature (20 K) saturation IRM after cooling in zero field (ZFC) or in a 2.5 T field (Fe) lrom 300 K, Howcver, potentially the most diagnostic magnetic parameter for magnetosome chain identification in bulk sediment samples is related to the difference hetween low temperature zero-field and field cooled 51 RMs on warming through the Verwey transition (T z J00 K). Intact chains of unoxidized magnetite magnetoSl)ll1eS have ratios of D,.c/t5ZFC greater than 2, where the parameter D is a measure of the amount of remanenCl' lost by warming through the Verwey transition. Disruption of the chain structure or conversion of the magnetosuilles to maghemite reduces the.) FC/OLl-C ratio to around L similar to values observed for some inorganic magnetite. rnaghemitc. greigitc and GS-15 particles. Numerical simulations of t5,.c/Dzvc ratios for simple binary mixtures of magnctosome chains and inorganic magnetic fractions suggest that the 15 njD zFc parameter can he a sensitive indicator of biogenic magnetite in the form of intact chains of magnetite magnetosomcs and can he a useful magnetic technique for identifying them in whole-sediment samples. The strength of our approach lies in the comparati\e case and rapidity with which magnetic measurements can be madc, compared to techniques such as electron III ic roscopy.

show abstract

Crystallochemical characterization of magnetic spinels prepared from aqueous solution

Cited by 59 publications

References 1 publication

Influence of Fe(II) on the Formation of the Spinel Iron Oxide in Alkaline Medium

Influence of Fe(II) on the Formation of the Spinel Iron Oxide in Alkaline Medium

The Effect of Vacuum Annealing of Magnetite and Zero-Valent Iron Nanoparticles on the Removal of Aqueous Uranium

Rock magnetic criteria for the detection of biogenic magnetite

Contact Info

Product

Resources

About