Occurrence and Constitution of Natural and Synthetic Ferrihydrite, a Widespread Iron Oxyhydroxide

Jambor, John L.; Dutrizac, J. E.

doi:10.1021/cr970105t

Cited by 829 publications

(714 citation statements)

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“…However, Fh frequently contains aggregates of which the internal surfaces may not be entirely accessible to N 2 , and the BET surface area calculated here would be lower than the real one. The PZC of Fh estimated from zeta potentials under different pH was 7.9, which was also similar to that of the previous studies (Jambor and Dutrizac, 1998).…”

Section: Structural Characterization Of Fhsupporting

confidence: 89%

“…1). The original Fh showed two broad reflections at 2θ of 35 and 62°, consisting with previous studies (Jambor and Dutrizac, 1998), and it confirmed the presence of two-line Fh particles. As the XRD patterns of Fh before and after adsorption were almost the same, the adsorption of phosphate and/or Zn(II) should have no evident impact on the crystal structure of Fh.…”

Section: Structural Characterization Of Fhsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

“…In the family of iron (oxyhydr)oxides, ferrihydrite (Fh) is considered as one of the most distinct minerals, as it is a precursor to other iron minerals such as goethite and hematite (Jambor and Dutrizac, 1998;Meng et al, 2014). Due to its extremely large surface area and chemically active surface groups, Fh shows strong capacity in the adsorption of heavy-metal cations and oxyanions and therefore has a close relationship with the geochemical cycling of these contaminants (Jambor and Dutrizac, 1998;Moon and Peacock, 2013). Furthermore, its abundance in the environment as well as easy availability and small toxicity also make it an excellent candidate in contaminant removal strategies (Hiemstra et al, 2009 interactions of Fh with heavy-metal cations and oxyanions have drawn significant concerns (Trivedi et al, 2004;Mallet et al, 2013), and the adsorption mechanisms of heavy-metal cations/oxyanions on Fh have been well studied, including ligand exchange (Mustafa et al, 2004;Das et al, 2013), electrostatic interactions , surface precipitation (Michael et al, 2013), etc.…”

Section: Introductionmentioning

confidence: 99%

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Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

et al. 2016

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h i g h l i g h t s• Phosphate and Zn(II) exhibited a synergistic adsorption on Ferrihydrite.• The effects of pH on the adsorption of the two contaminants were investigated.• XPS and ATR-FTIR demonstrated ternary complexes were formed on Ferrihydrite.• A phosphate-bridged ternary complexes model was proposed. a r t i c l e i n f o b s t r a c tFerrihydrite (Fh) is of great importance in affecting the migration and transformation of heavy-metal cations and oxyanions. To advance the understanding of co-adsorption reactions on Fh surface, the coadsorption of phosphate and Zn(II) from aqueous solution to a synthesized Fh was determined. The batch experiments demonstrated a synergistic adsorption of phosphate and Zn(II) on Fh. In the pH range of 3.5-6, the adsorption of the two contaminants showed strong pH dependence in the single solute adsorption systems, but the dependence alleviated in the simultaneous adsorption system. X-ray photoelectron spectroscopy (XPS) revealed that the chemical shifts of Zn 2p 1/2 and Zn 2p 3/2 binding energies were more significant than that of P 2p in the single and simultaneous adsorption systems. On the other side, in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) observed increased formation of outer-and inner-sphere complexes of phosphate in the simultaneous system. Thus, the synergistic adsorption of the two contaminants could be attributed to the formation of ternary complexes as well as electrostatic interactions, while surface precipitation could not be completely ruled out. On the basis of the results from both the batch adsorption experiments and structural characterization, these two contaminants were likely to form phosphate-bridged ternary complexes (≡Fe-P-Zn) in the simultaneous adsorption system.

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Section: Structural Characterization Of Fhsupporting

confidence: 89%

Section: Structural Characterization Of Fhsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

et al. 2016

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“…However, the precipitates do not have the composition Fe(OH) 3 , and they are not amorphous although their X-ray diffracting properties are poor. It was recognized that many of these precipitates are actually ferrihydrite [9].…”

Section: Introductionmentioning

confidence: 99%

Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS)

Li¹,

Wang

et al. 2012

Desalination and Water Treatment

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(2012) Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS), Desalination and Water Treatment, 49:1-3, 157-164, DOI: 10.1080/19443994.2012.708222 To link to this article: http://dx.doi.org/10. 1080/19443994.2012.708222 PLEASE SCROLL DOWN FOR ARTICLETaylor & Francis makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Ferrihydrite is effective in arsenic removal because of the considerable amount of active hydroxyl groups. Solid-liquid separation of the arsenic adsorbed ferrihydrite from aqueous solution is important for the arsenic treatment technology. Coagulation is a promising process for ferrihydrite separation. Effects of different coagulants on arsenic adsorbed ferrihydrite settlement were investigated. Surface charge significantly decreased after arsenic was adsorbed on ferrihydrite. Turbidity, iron and arsenic removal efficiencies were used to characterize the ferrihydrite settling process. Turbidity removal efficiency with polyferric sulfate (PFS) added was 98.2% when pH was 5.0. Meanwhile, the turbidity removal rate with polyaluminium chloride (PAC) added was 96.3-97.3% when the pH of colloidal suspensions was 7.0-9.0. Arsenic or iron removal rate after 30 min settling was improved from about 40 to 80% with coagulants added. The mean size of flocs after coagulation process was 61.8 lm after PFS was added, or 71.6 lm after PAC was added when the pH was 6.5. The floc structure of ferrihydrite became more compact and stable with PAC or PFS added.

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Detailed magnetic monitoring of the enhanced magnetism of ferrihydrite along its progressive transformation into hematite

et al. 2016

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Under certain aging conditions, ferrihydrite evolves into hematite through intermediate products of enhanced magnetism. Although the magnetic properties of the end product, hematite, are to date satisfactorily known, those of ferrihydrite (and especially the products of its progressive aging) are not sufficiently explored. To this end, magnetic experiments, conducted mostly by using alternating magnetic fields, have been performed. The results reveal that two‐line ferrihydrite exhibits conspicuous low‐temperature spin glass behavior, a new finding that, on the other hand, could be expected given the previous microstructural observations that described this mineral as a very disordered gel. Upon aging, a progressive increase of the effective magnetic moment per iron ion is detected, in agreement with previous observations that ascribed ferrimagnetic character to an intermediate crystalline phase (sometime called ferriferrihydrite) that disappears just before the full transformation into hematite. Transmission electron microscopy observations suggest that this intermediate crystalline phase nucleates at the expense of the primordial gel, remaining physically attached to it until complete transformation into hematite. This microstructural picture appears well supported as, upon aging, the glassy magnetic dynamics found in ferrihydrite persists for the aged products even when dispersed in a nonmagnetic matrix, very likely because part of the so grown ferrimagnetic nanoparticles form aggregates within remains of the nontransformed gel. We propose a coherent model of ferrihydrite aging, based on integrated microstructural and magnetic observations, which is useful for the identification of aging products in geological and biological environments.

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Occurrence and Constitution of Natural and Synthetic Ferrihydrite, a Widespread Iron Oxyhydroxide

Abstract: face sites are highly amenable to the adsorption of foreign species and, combined with the large surface area, may account for the high adsorptive capacity of ferrihydrite. The adsorption of various ions generally retards the transformation of ferrihydrite to goethite or hematite.

Cited by 829 publications

References 281 publications

Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

Co-adsorption of phosphate and zinc(II) on the surface of ferrihydrite

Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS)

Detailed magnetic monitoring of the enhanced magnetism of ferrihydrite along its progressive transformation into hematite

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