The interaction of silicic acid with iron(III) and uranyl ions in dilute aqueous solution

Porter, Richard A.; Weber, Walter J.

doi:10.1016/0022-1902(71)80219-1

Cited by 48 publications

(27 citation statements)

References 14 publications

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“…3). The largest relative differences in the optical density of solutions containing Si(OH) 4 and free of it were observed at l = 322 nm, in agreement with the data of [1]. The experimental As the dissociation of Si(OH) 4 under these conditions is negligible, its concentration is virtually equal to the total concentration of the silicate in solution minus the concentration of uranyl silicate complexes.…”

Section: Hydrolysis Of Uo 2 2+supporting

confidence: 88%

“…An increase in the optical density of the solution with an increase in pH to 3.75 in [1] was appreciably weaker than in our run no. 5 (Table 2) performed under similar conditions.…”

Section: Possible Causes Of Inconsistency Of Published Datacontrasting

confidence: 70%

“…We performed the spectrophotometric measurements and calculations by almost the same procedure as in [1], but the silicate in [1] was a fortiori polymeric. An increase in the optical density of the solution with an increase in pH to 3.75 in [1] was appreciably weaker than in our run no.…”

Section: Possible Causes Of Inconsistency Of Published Datamentioning

confidence: 99%

“…(1) What is the cause of major disagreement between the published values of the constant K (without understanding these causes, the choice of the constant recommended in [9] seems rather arbitrary)? (2) How does the polymerization of Si(OH) 4 …”

mentioning

confidence: 99%

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A Spectrophotometric Study of the Interaction of Uranyl Ions with Orthosilicic Acid and Polymeric Silicic Acids in Aqueous Solutions

Yusov

Федосеев

2005

Radiochemistry

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The interaction of UO 2 2+ ions with orthosilicic acid Si(OH) 4 and polymeric silicic acids (PSAs) was studied spectrophotometrically. The equilibrium constant of the reaction UO 2 2+ + Si(OH) 4 = UO 2 OSi(OH) 3 + + H + in solutions with the ionic strength I = 0.13 0.2 is log K = 32.56 + 0.09 (log K 0 = 32.29 + 0.09 recalculated to I = 0); the stability constant of the complex UO 2 OSi(OH) 3 + (I = 0) is log b 0 = 7.52 + 0.09. Formation of small oligomers (degree of polymerization n < 4) has virtually no effect on the apparent constant K. When high polymers are formed (n > 100), the apparent equilibrium constant decreases by a factor of 233, and the [true] equilibrium constant recalculated to the actual concentration of silanol groups increases by a factor of 33 4. The absorption spectrum of the complex UO 2 OSi(OH) 3 + was obtained by treatment of the experimental spectra; it has an absorption maximum in the visible range at 422.5 nm, e 422.5 = 35 + 2 l mol !1 cm !1 . At pH higher than 53 6, complexes of UO 2 2+ with PSAs of the composition UO 2 (=SiO) 2 (=SiOH) m !2 are formed. The absorption spectrum of such a complex was obtained.Much attention is given today to the interaction of f-element ions with orthosilicic acid Si(OH) 4 and other silicate species. It has been shown that silicate ions appreciably affect the state and behavior of UO 2 2+ and other actinide ions under widely varied conditions [138]. The interaction of uranyl ions with orthosilicic acid at pH 33 4.5 is described by the equation [13 6, 9] UO 2 2+ + Si(OH) 4 = UO 2 OSi(OH) 3 + + H + (1) with the equilibrium constant [UO 2 OSi(OH) 3 + ][H + ] K = ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ. (2) [UO 2 2+ ][Si(OH) 4 ] The values given in the literature for log K range from 31.37 [5] to 32.92 [3] in 0.13 0.2 M NaClO 4 . Jensen and Choppin [3] believe that the major cause of this inconsistency is the polymerization of Si(OH) 4 , which took place in some studies. Polymeric silicic acids (PSAs) were believed, without due proof, to interact with the UO 2 2+ ion more strongly. The value recommended by the thermodynamic database of the year 2003 [9] is log K = 32.11 + 0.10 at the ionic strength I = 0.13 0.2, whence log K 0 = 31.84 + 0.10 at I = 0 (T = 293.15 K). The interaction of Si(OH) 4 with the PuO 2 2+ ion [10] appeared to be considerably weaker: log K = 33.91 + 0.17 at I = 0.2. Relevant data for the NpO 2 2+ ion are lacking.Thus, the following questions concerning the interaction of hexavalent actinides with Si(OH) 4 remain to be answered. (1) What is the cause of major disagreement between the published values of the constant K (without understanding these causes, the choice of the constant recommended in [9] seems rather arbitrary)?(2) How does the polymerization of Si(OH) 4 affect K?(3) What is the trend in variation of K in the series U(VI)3Np(VI)3Pu(VI)?Here and in the subsequent paper [11] we report on a direct spectrophotometric study of the interaction of Si(OH) 4 and PSAs with the UO 2 2+ and NpO 2 2+ ions.EXPERIMENTAL Uranyl solutions were prepared by dilution of...

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Section: Hydrolysis Of Uo 2 2+supporting

confidence: 88%

“…An increase in the optical density of the solution with an increase in pH to 3.75 in [1] was appreciably weaker than in our run no. 5 (Table 2) performed under similar conditions.…”

Section: Possible Causes Of Inconsistency Of Published Datacontrasting

confidence: 70%

Section: Possible Causes Of Inconsistency Of Published Datamentioning

confidence: 99%

mentioning

confidence: 99%

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A Spectrophotometric Study of the Interaction of Uranyl Ions with Orthosilicic Acid and Polymeric Silicic Acids in Aqueous Solutions

Yusov

Федосеев

2005

Radiochemistry

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“…The formation of Fe-hydroxide reduced the active surface area of pyrite by surface coating as well as the Porter and Weber (1971), and Weber and Stumm (1965). The Fe 3+ -monomeric silicic acid complex was reported as a chemically inert species in solution (Olson and Omelia, 1973).…”

Section: Chemical Composition Determined With Xrfmentioning

confidence: 99%

Suppression of Pyrite Oxidation by Formation of Iron Hydroxide and Fe(III)-silicate Complex under Highly Oxidizing Condition

Lee¹,

Chon²,

Kim³

2011

Korean Journal of Soil Science and Fertilizer

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Acid drainage generated by pyrite oxidation has caused the acidification of soil and surface water, the heavy metal contamination and the corrosion of structures in abandoned mine and construction sites. The applicability of Na-acetate (Na-OAc) buffer and/or Na-silicate solution was tested for suppressing pyrite oxidation by reacting pyrite containing rock and treating solution and by analyzing solution chemistry after the reaction. A finely ground Mesozoic andesite containing 10.99% of pyrite and four types of reacting solutions were used in the applicability test: 1) H 2 O 2 , 2) H 2 O 2 and Na-silicate, 3) H 2 O 2 and 0.01M Na-OAc buffer at pH 6.0, and 4) H 2 O 2 , Na-silicate and 0.01M Na-OAc buffer at pH 6.0. The pH in the solution after the reaction with the andesite sample and the solutions was decreased with increasing the initial H 2 O 2 concentration but the concentrations of Fe and SO 4 2-were increased 10 -20 times. However, the pH of the solution after the reaction increased and the concentrations of Fe and SO 4 2-decreased in the presence of Na-acetate buffer and with increasing Na-silicate concentration at the same H 2 O 2 concentration. The solution chemistry indicates that Na-OAc buffer and Na-silicate suppress the oxidation of pyrite due to the formation of Fe-hydroxide and Fe-silicate complex and their coating on the pyrite surface. The effect of Na-OAc buffer and Na-silicate on reduction of pyrite oxidation was also confirmed with the surface examination of pyrite using scanning electron microscopy (SEM). The result of this study implies that the treatment of pyrite containing material with the Na-OAc buffer and Na-silicate solution reduces the generation of acid drainage.

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The behavior of asbestos–cement pipe under various water quality conditions: Part 2, theoretical considerations

Schock¹,

Buelow²

1981

Journal AWWA

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A water chemical model involving the complexation and solubility equilibria of calcium, magnesium, zinc, iron, manganese, silica, chloride, orthophosphate, and carbonate has been developed and applied to laboratory pipe‐loop‐coupon and field data on asbestos–cement pipe. Calculation of the saturation states of the relevant solids enables graphic guides to be prepared for the prediction of dosage levels for in‐situ pipe coating by zinc compounds as well as protection afforded by coatings formed by natural inhibitory constituents of the water.

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The interaction of silicic acid with iron(III) and uranyl ions in dilute aqueous solution

Cited by 48 publications

References 14 publications

A Spectrophotometric Study of the Interaction of Uranyl Ions with Orthosilicic Acid and Polymeric Silicic Acids in Aqueous Solutions

A Spectrophotometric Study of the Interaction of Uranyl Ions with Orthosilicic Acid and Polymeric Silicic Acids in Aqueous Solutions

Suppression of Pyrite Oxidation by Formation of Iron Hydroxide and Fe(III)-silicate Complex under Highly Oxidizing Condition

The behavior of asbestos–cement pipe under various water quality conditions: Part 2, theoretical considerations

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