TY - JOUR
T1 - Chemical Speciation of Hg(ii) with Environmental Inorganic Ligands
AU - Powell, Kipton J.
AU - Brown, Paul L.
AU - Byrne, Robert H.
AU - Gajda, Tamas
AU - Hefter, Glenn
AU - Sjöberg, Staffan
AU - Wanner, Hans
PY - 2004/1/1
Y1 - 2004/1/1
N2 - Complex formation between Hg(ii) and the common environmental ligands Cl − , OH − , CO 3 2− , SO 4 2− , and PO 4 3− can have profound effects on Hg(ii) speciation in natural waters with low concentrations of organic matter. Hg(ii) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log 10 β p,q,r ° and the associated reaction enthalpies, Δ r H m °, valid at I m = 0 mol kg −1 and 25°C, along with the equations and specific ion interaction coefficients required to calculate log 10 β p,q,r values at higher ionic strengths and other temperatures are also presented. Under typical environmental conditions Hg(ii) speciation is dominated by the reactions Hg 2+ + 2Cl − ↔ HgCl 2(aq) (log 10 β 2 ° = 14.00 ± 0.07), Hg 2+ + Cl − + H 2 O ↔ Hg(OH)Cl (aq) + H + (log 10 β ° = 4.27 ± 0.35), and Hg 2+ + 2H 2 O ↔ Hg(OH) 2(aq) + 2H + (log 10 * β 2 ° = −5.98 ± 0.06).
AB - Complex formation between Hg(ii) and the common environmental ligands Cl − , OH − , CO 3 2− , SO 4 2− , and PO 4 3− can have profound effects on Hg(ii) speciation in natural waters with low concentrations of organic matter. Hg(ii) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log 10 β p,q,r ° and the associated reaction enthalpies, Δ r H m °, valid at I m = 0 mol kg −1 and 25°C, along with the equations and specific ion interaction coefficients required to calculate log 10 β p,q,r values at higher ionic strengths and other temperatures are also presented. Under typical environmental conditions Hg(ii) speciation is dominated by the reactions Hg 2+ + 2Cl − ↔ HgCl 2(aq) (log 10 β 2 ° = 14.00 ± 0.07), Hg 2+ + Cl − + H 2 O ↔ Hg(OH)Cl (aq) + H + (log 10 β ° = 4.27 ± 0.35), and Hg 2+ + 2H 2 O ↔ Hg(OH) 2(aq) + 2H + (log 10 * β 2 ° = −5.98 ± 0.06).
UR - https://digitalcommons.usf.edu/msc_facpub/1632
UR - https://doi.org/10.1071/CH04063
U2 - 10.1071/CH04063
DO - 10.1071/CH04063
M3 - Article
VL - 57
JO - Australian Journal of Chemistry
JF - Australian Journal of Chemistry
ER -