Adsorption and Precipitation of Aqueous Zn(II) on Alumina Powders

Trainor, Thomas P.; Brown, Gordon E.; Parks, George S.

doi:10.1006/jcis.2000.7111

Cited by 169 publications

(182 citation statements)

References 66 publications

Supporting

Mentioning

147

Contrasting

Order By: Relevance

“…For example, Trainor et al (2000) observed the formation of (Zn,Al)-hydrotalcite upon Zn sorption on alumina in conditions of undersaturation with respect to the homogeneous precipitation of Zn solids, and similar results were obtained with nickel and cobalt on the same or other Alcontaining substrates (Espinose De La Caillerie et al, 1995;Scheidegger et al, 1997;Scheckel et al, 2000;Elzinga and Sparks, 2001). This phenomenon can be rationalized by considering that the activity of Al is higher in the immediate vicinity of an aluminous solid and,…”

Section: Thermodynamic Stability Ofsupporting

confidence: 60%

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

Panfili

Manceau

Sarret

et al. 2005

Geochimica et Cosmochimica Acta

122

129

View full text Add to dashboard Cite

Running Title: Effect of phytostabilzation on Zn speciation in dredged sediment 2 ABSTRACTThe maintenance of waterways generates large amounts of dredged sediments, which are deposited on adjacent land surfaces. These sediments are often rich in metal contaminants and present a risk to the local environment. Understanding how the metals are immobilized at the molecular level is critical for formulating effective metal containment strategies, such as phytoremediation. In the present work, the mineralogical transformations of Zn Seven Zn species were identified at the micrometer-scale : sphalerite, gahnite, franklinite, Zncontaining ferrihydrite and phosphate, (Zn-Al)-hydrotalcite, and Zn-substituted, kerolite-like, trioctahedral phyllosilicate. Bulk fractions of each species were quantified by LSF of the powder EXAFS spectra to linear combinations of the identified Zn species spectra.In the untreated and unvegetated sediment, Zn was distributed as ~50 % (mole ratio of total Zn) sphalerite, ~40 % Zn-ferrihydrite, and ~10-20 % (Zn-Al)-hydrotalcite plus Znphyllosilicate. In unvegetated but amended sediments (AP and TS), ZnS and Zn-ferrihydrite each decreased by 10 to 20 % and were replaced by Zn-phosphate (~30-40 %). In the presence of plants, ZnS was almost completely dissolved and the released Zn bound to phosphate (~40-60 %) and to Zn phyllosilicate plus (Zn,Al)-hydrotalcite (~20-40 %). Neither the plant species 3 nor the co-addition of mineral amendment affected the Zn speciation in the vegetated sediment.The sediment pore waters were supersaturated with respect to Zn-containing trioctahedral phyllosilicate, near-saturation with respect to Zn-phosphate, and strongly undersaturated with respect to (Zn,Al)-hydrotalcite. Therefore, the formation of (Zn,Al)-hydrotalcite in slightly alkaline conditions ought to result from heterogenous precipitation on mineral surface. 4

show abstract

Section: Thermodynamic Stability Ofsupporting

confidence: 60%

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

Panfili

Manceau

Sarret

et al. 2005

Geochimica et Cosmochimica Acta

122

129

View full text Add to dashboard Cite

show abstract

“…Therefore, Zn 2+ (aq) is sixfold coordinated with oxygen, whereas ZnO(s) is fourfold coordinated, which agrees with previous work [25,26,44]. It has been reported that the most common coordination geometries of hydrous Zn(II) are octahedron (i.e., Zn(H 2 O) 2+ 6 ) with a Zn-O bond length of 2.07-2.18 Å and tetrahedron (i.e., ZnO(s), Zn(OH) 2− 4 ) with a Zn-O bond length of 1.92-1.99 Å [45]. Zhu and Pan [46] reported that in acidic solutions (pH 6.9) Zn 2+ (aq) is present in the form of octahedron with an average Zn-O bond length of 2.08 Å.…”

Section: The Microscopic Structure Of Adsorbed Zn(ii)mentioning

confidence: 99%

“…In recent years, the EXAFS technique has been increasingly employed for providing structural and compositional information of surface complexes [19,20], which often offers critical insights into the underlying adsorption/desorption mechanisms [21][22][23]. This facilitates our understanding of commonly observed phenomena such as sorption hysteresis and slow sorption/desorption processes.…”

Section: Introductionmentioning

confidence: 99%

EXAFS studies on adsorption irreversibility of Zn(II) on TiO2: Temperature dependence

Pan

Zhang

et al. 2008

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Adsorption irreversibility of Zn(II) on TiO 2 at various temperatures was studied using a combination of classical macroscopic methods and extended X-ray absorption fine structure (EXAFS) spectroscopy. When the temperature was increased from 5 to 40 • C, the Zn(II) adsorption capacity increased by 130%, and adsorbed Zn(II) became more reversible. The standard Gibbs free energy change ( G 0 ) of the adsorption reaction at 5, 20, and 40 • C was determined to be −19.58 ± 0.30, −22.28 ± 0.10, and −25.14 ± 0.21 kJ mol −1 , respectively. And the standard enthalpy ( H 0 ) and entropy ( S 0 ) were 24.55 ± 2.91 kJ mol −1 and 159.13 ± 0.53 J mol −1 K −1 , respectively. EXAFS spectra results showed that the hydrated Zn(II) was adsorbed through fourfold coordination with an average Zn-O bond distance of 1.98 ± 0.01 Å. Two Zn-Ti atomic distances of 3.25 ± 0.02 and 3.69 ± 0.03 Å were observed, which corresponded to an edge-sharing linkage mode (strong adsorption) and a cornersharing linkage mode (weak adsorption), respectively. As the temperature increased from 5 to 40 • C, the number of strong adsorption sites (N 1 ) remained relatively constant while the number for the weak adsorption sites (N 2 ) increased by 31%. These results indicate that the net gain in adsorption capacity and the decreased adsorption irreversibility at elevated temperatures were due to the increase in available weak adsorption sites (N 2 ) or the decrease in the ratio of N 1 /N 2 . Both the macroscopic sorption/desorption equilibrium data and the molecular level evidence of this study suggest that in a given environmental system (e.g., soils or natural waters) zinc and other similar heavy metals are likely more mobile at higher temperatures.

show abstract

“…More recently, LDHs have been shown to be important compounds in water oxidation catalysis 18 . Al-based LDHs occurring in soil environments have been identified for reactions with iron(II), cobalt, Ni and zinc 11,13,[19][20][21][22][23][24][25] .…”

mentioning

confidence: 99%

Real-time QEXAFS spectroscopy measures rapid precipitate formation at the mineral–water interface

Siebecker

Khalid

et al. 2014

Nat Commun

View full text Add to dashboard Cite

Reactions at the mineral-water interface are central to numerous geochemical processes and have consequences at local, regional and global scales. They are also important in materials science research. Kinetics greatly influences mineral-water interface reactions; however, there are few kinetic data in real-time and at the molecular scale. Here we report real-time data illustrating the rapid formation of nickel aluminium-layered double hydroxide precipitates at the mineral-water interface in a flow environment in as little as 31-40 min. Layered double hydroxides have a variety of applications in environmental remediation and materials science. The real-time data shown here enhance our fundamental understanding of the kinetics of mineral-water interface processes, such as adsorption, dissolution and precipitation, by illustrating their rapid and simultaneous occurrence in a dynamic environment. Both precipitation and adsorption can occur on the same rapid timescale.

show abstract

Adsorption and Precipitation of Aqueous Zn(II) on Alumina Powders

Cited by 169 publications

References 66 publications

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

EXAFS studies on adsorption irreversibility of Zn(II) on TiO2: Temperature dependence

Real-time QEXAFS spectroscopy measures rapid precipitate formation at the mineral–water interface

Contact Info

Product

Resources

About