Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems.

Erla Hafsteinsdóttir, Duanne White, Damian Gore, Scott Stark

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Orthophosphate �xation of metal contaminated soils in environments that undergo freezeethaw cycles is understudied. Freezeethaw cycling potentially in�uences the reaction rate, mineral chemical stability and physical breakdown of particles during �xation. This study determines what products form when phosphate (triple superphosphate [Ca(H2PO4)2] or sodium phosphate [Na3PO4]) reacts with lead (PbSO4 or PbCl2) in simple chemical systems in vitro, and assesses potential changes in formation during freezee thaw cycles. Systems were subjected to multiple freezeethaw cycles from �10 C to �20 C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freezeethaw cycles. Low temperature lead orthophosphate reaction ef�ciency varied according to both phosphate and lead source; the most time-ef�cient pyromorphite formation was observed when PbSO4 and Na3PO4 were present together. These �ndings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate.
Original languageEnglish
Pages (from-to)3496-3503
Number of pages8
JournalEnvironmental Pollution
Volume159
Issue number2
DOIs
Publication statusPublished - 2011

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Phosphates
Lead
Metals
Chemical stability
Freezing
X ray diffraction analysis
Reaction rates
Minerals
Soil
Sodium
X-Rays
Soils
Temperature
pyromorphite

Cite this

Hafsteinsdóttir, Erla ; White, Duanne ; Gore, Damian ; Stark, Scott. / Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems. In: Environmental Pollution. 2011 ; Vol. 159, No. 2. pp. 3496-3503.
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Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems. / Hafsteinsdóttir, Erla; White, Duanne; Gore, Damian; Stark, Scott.

In: Environmental Pollution, Vol. 159, No. 2, 2011, p. 3496-3503.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems.

AU - Hafsteinsdóttir, Erla

AU - White, Duanne

AU - Gore, Damian

AU - Stark, Scott

PY - 2011

Y1 - 2011

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AB - Orthophosphate �xation of metal contaminated soils in environments that undergo freezeethaw cycles is understudied. Freezeethaw cycling potentially in�uences the reaction rate, mineral chemical stability and physical breakdown of particles during �xation. This study determines what products form when phosphate (triple superphosphate [Ca(H2PO4)2] or sodium phosphate [Na3PO4]) reacts with lead (PbSO4 or PbCl2) in simple chemical systems in vitro, and assesses potential changes in formation during freezee thaw cycles. Systems were subjected to multiple freezeethaw cycles from �10 C to �20 C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freezeethaw cycles. Low temperature lead orthophosphate reaction ef�ciency varied according to both phosphate and lead source; the most time-ef�cient pyromorphite formation was observed when PbSO4 and Na3PO4 were present together. These �ndings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate.

KW - Metal fixation

KW - Freeze thaw

KW - Lead minerals

KW - Phosphate

KW - Pyromorphite

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DO - 10.1016/j.envpol.2011.08.026

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JO - Environmental Pollution

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SN - 0269-7491

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