Solubility and speciation of plutonium(VI) with orthophosphate

Weger, Hans Thomas

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https://hdl.handle.net/2142/23058 Copy

Description

Title

Solubility and speciation of plutonium(VI) with orthophosphate

Author(s)

Weger, Hans Thomas

Issue Date

1994

Doctoral Committee Chair(s)

Landsberger, Sheldon

Department of Study

Nuclear, Plasma, and Radiological Engineering

Discipline

Nuclear, Plasma, and Radiological Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Engineering, Nuclear
• Geochemistry

Language

eng

Abstract

• Pu(VI) speciation and solubility with phosphate was examined at pH from 0.3 to 12.2, Pu(VI) concentrations from 5 $\times\ {\rm 10}\sp{-5}$ M to 1.3 $\times\ {\rm 10}\sp{-3}$ M and phosphate concentrations up to 0.6 M. Absorption spectroscopy, solubility experiments, scanning electron microscopy and photon correlation spectroscopy were utilized.
• The species PuO$\sb2{\rm H}\sb2{\rm PO}\sb4\sp{+}$ and PuO$\sb2{\rm (H}\sb2{\rm PO}\sb4{\rm )}\sb2$ formed at pH $$ 2.4. The aqueous plutonium concentration was 10$\sp{-5}$ M at pH from 3.5 to 6 and 10$\sp{-6}$ M at pH from 6 to 8. Plutonium(VI) favored complexation with phosphate only at Pu(VI) concentrations greater than 1.5 $\times\ {\rm 10}\sp{-4}$ M. Evidence exists that mixed phosphate-carbonate species were formed.
• The species (PuO$\sb2{\rm HPO}\sb4$)$\sb{\rm n}$ and (PuO$\sb2{\rm NaPO}\sb4$)$\sb{\rm n},$ characterized by absorption bands at 842.3 $\pm$ 0.05 nm and 846 $\pm$ 0.05 nm, are formed at pH between 2.4 and 9. The species (PuO$\sb2{\rm HPO}\sb4$)$\sb{\rm n}$ has $\varepsilon$ = 340 $\pm$ 20, log $\beta$ = $-$4.32 + 10.73n $\pm$ ($-$0.20 + 0.41n) and log $\beta\sp{T}$ = log $\beta$ + 1.2n $\pm$ ($-$0.10 + 0.41n). The species (PuO$\sb2{\rm NaPO}\sb4{\rm )}\sb{\rm n}$ has $\varepsilon$ = 380 $\pm$ 20 and log $\beta\sp{T}\sb{846}$ = log $\beta\sp{T}\sb{842}$ - (4.4 $\pm$ 0.3)n. At pH $>$ 9, Pu(VI)-phosphate species formed with absorption bands at 857 $\pm$ 1 nm ($\varepsilon$ = 200 $\pm$ 30) and 866 nm ($\varepsilon$ = 123 $\pm$ 15).

Type of Resource

text

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http://hdl.handle.net/2142/23058

Copyright and License Information

Copyright 1994 Weger, Hans Thomas

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