Adsorption of selenate onto ferrihydrite, goethite, and lepidocrocite under neutral pH conditions

Das, Soumya; Hendry, M. Jim; Essilfie-Dughan, Joseph

doi:10.1016/j.apgeochem.2012.10.026

Cited by 98 publications

(88 citation statements)

References 37 publications

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“…The Gibbs free energy change (ΔG<0) and experimental results both shows that iron oxides containing Fe(II) such as green rust, ferrous hydroxide, mackinawite, siderite and magnetite could also achieve the transition from selenate/selenite to Se 0 [40–41, 46–48]. Additionally, iron oxides such as ferrihydrite have been considered as good adsorbents for selenium removal, forming inner- and/or outer-sphere surface complexes [49–50]. Therefore, selenium removal by iron nanoparticles involves both reduction and adsorption mechanism.…”

Section: Resultsmentioning

confidence: 99%

Engineered iron/iron oxide functionalized membranes for selenium and other toxic metal removal from power plant scrubber water

Gui

Papp

Colburn

et al. 2015

Journal of Membrane Science

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The remediation of toxic metals from water with high concentrations of salt has been an emerging area for membrane separation. Cost-effective nanomaterials such as iron and iron oxide nanoparticles have been widely used in reductive and oxidative degradation of toxic organics. Similar procedures can be used for redox transformations of metal species (e.g. metal oxyanions to elemental metal), and/or adsorption of species on iron oxide surface. In this study, iron-functionalized membranes were developed for reduction and adsorption of selenium from coal-fired power plant scrubber water. Iron-functionalized membranes have advantages over iron suspension as the membrane prevents particle aggregation and dissolution. Both lab-scale and full-scale membranes were prepared first by coating polyvinylidene fluoride (PVDF) membranes with polyacrylic acid (PAA), followed by ion exchange of ferrous ions and subsequent reduction to zero-valent iron nanoparticles. Water permeability of membrane decreased as the percent PAA functionalization increased, and the highest ion exchange capacity (IEC) was obtained at 20% PAA with highly pH responsive pores. Although high concentrations of sulfate and chloride in scrubber water decreased the reaction rate of selenium reduction, this was shown to be overcome by integration of nanofiltration (NF) and iron-functionalized membranes, and selenium concentration below 10 μg/L was achieved.

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Section: Resultsmentioning

confidence: 99%

Engineered iron/iron oxide functionalized membranes for selenium and other toxic metal removal from power plant scrubber water

Gui

Papp

Colburn

et al. 2015

Journal of Membrane Science

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“…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%

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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“…Thus, it is imperative to develop novel, efficient and friendly materials and technologies to remove these contaminants. A number of iron oxides including goethite [2,3], hematite [4,5], magnetite [6,7], ferrihydrite [8,9] and lepidocrocite [10,11] were applied to adsorb heavy metal species and initiate the advanced oxidation processes (AOPs) as heterogeneous catalysts for organic degradation.…”

Section: Introductionmentioning

confidence: 99%

The distinct effects of Mn substitution on the reactivity of magnetite in heterogeneous Fenton reaction and Pb(II) adsorption

Liang

Zhu

Wei

et al. 2014

Journal of Colloid and Interface Science

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Adsorption of selenate onto ferrihydrite, goethite, and lepidocrocite under neutral pH conditions

Cited by 98 publications

References 37 publications

Engineered iron/iron oxide functionalized membranes for selenium and other toxic metal removal from power plant scrubber water

Engineered iron/iron oxide functionalized membranes for selenium and other toxic metal removal from power plant scrubber water

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

The distinct effects of Mn substitution on the reactivity of magnetite in heterogeneous Fenton reaction and Pb(II) adsorption

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