Chemical Speciation of Environmentally Significant Metals: An IUPAC contribution to reliable and rigorous computer modelling

2015 ◽  
Vol 37 (1) ◽  
Author(s):  
Kipton J. Powell ◽  
Paul L. Brown ◽  
Robert H. Byrne ◽  
Tamas Gajda ◽  
Glenn Hefter ◽  
...  
Keyword(s):  
Metal Ions ◽  
Natural Waters ◽  
Chemical Speciation ◽  
Computer Modelling ◽  
Adsorbed Species ◽  
Mineral Phases ◽  
Organic Complexes ◽  
Anionic Ligands ◽  
Ligand Species ◽  
Metal Ligand

The mobility and bioavailability of metal ions in natural waters depend on their chemical speciation, which involves a distribution of the metal ions between different complex (metal-ligand) species, colloid-adsorbed species and insoluble phases, each of which may be kinetically labile or inert. For example, in fresh water the metal ions are distributed among organic complexes (e.g., humates), colloids (e.g., as surface-adsorbed species on colloidal phases such as FeOOH), solid phases (e.g., hydroxide, oxide, carbonate mineral phases), and labile complexes with the simple inorganic anionic ligands commonly present in natural waters (e.g., for Zn

Rates of Reaction of Dissolved Oxygen With Scavengers in Sweet and Sour Brines

CORROSION ◽  
1969 ◽  
Vol 25 (10) ◽  
pp. 397-404 ◽  
Author(s):  
E. S. SNAVELY ◽  
F. E. BLOUNT
Keyword(s):  
Transition Metal ◽  
Dissolved Oxygen ◽  
Metal Ions ◽  
Induction Period ◽  
Natural Waters ◽  
Reaction Rate ◽  
Transition Metal Ions ◽  
Zero Order ◽  
Laboratory Apparatus ◽  
High Ph

Abstract Rates of reaction of dissolved oxygen with H2S were measured in a laboratory apparatus using a polarographic type instrument for the measurement of oxygen concentrations. Results show that oxidation occurs only at high pH in the absence of catalytic species. The reaction is catalyzed by transition metal ions in the order Ni++>Co ++>Mn++>Cu++>Fe++. In all cases, the reaction rate increases with pH and is at first complex but becomes zero-order with respect to oxygen after a brief induction period. Some natural waters contain sufficient catalysts that additional amounts are not required for scavenging O2 with SO2 or Na2SO3. Sour waters cannot be scavenged with SO2 or Na2SO3 because of ineffectiveness of catalysts.

scholarly journals Mixed Ligand Complexes of Transition Metal Ions with Selective Bio-Ligands in Surfactant-Water Mixtures

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3182-3190
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Metal Ions ◽  
Chemical Speciation ◽  
Transition Metal Ions ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Stacking Interactions ◽  
Micellar Media ◽  
Chelate Effect

Chemical speciation of ternary complexes of L-arginine and L-aspartic acid with essential transition metal ions was studied pH metrically. The following MLX, MLXH and ML2X ternary species are detected and reported in this paper. The existence of different ternary species is established from modeling studies using the computer program MINIQUAD75. The relative concentrations (M: L: X=1:2:2, 1:2:4, 1:4:2) and stabilities of the ternary species are compared with those of binary species. The extra stability associated with the ternary complexes is attributed to factors such as charge neutralization, chelate effect, stacking interactions and hydrogen bonding. Trend in variation of stability constants with the change in the mole fraction of the surfactant in various micellar media is explained on the basis of electrostatic and non-electrostatic forces. Distribution diagrams in relation to pH and plausible structures were presented.

Complexation of Dissolved Organic Matter with Trace Metal Ions in Natural Waters

2012 ◽  
pp. 769-849 ◽  
Author(s):  
Khan M. G. Mostofa ◽  
Cong-qiang Liu ◽  
Xinbin Feng ◽  
Takahito Yoshioka ◽  
Davide Vione ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Trace Metal ◽  
Metal Ions ◽  
Natural Waters ◽  
Trace Metal Ions

Organic complexes of iron and aluminium in natural waters

Nature ◽  
1976 ◽  
Vol 260 (5550) ◽  
pp. 418-420 ◽  
Author(s):  
EDWARD M. PERDUE ◽  
KEVIN C. BECK ◽  
J. HELMUT REUTER
Keyword(s):  
Natural Waters ◽  
Organic Complexes

Comparative Calorimetric and 1H N.M.R. Studies of the Interaction of Ag(I) With a Series of Mixed-Donor Macrocycles Incorporating Nitrogen, Oxygen and or Sulfur Donor Atoms

1988 ◽  
Vol 41 (9) ◽  
pp. 1347 ◽  
Author(s):  
D Baldwin ◽  
LF Lindoy ◽  
DP Graddon
Keyword(s):  
Stability Constants ◽  
Macrocyclic Ligands ◽  
Enthalpies Of Formation ◽  
Calorimetric Titration ◽  
Ligand Ratio ◽  
Deuterated Derivative ◽  
Titration Data ◽  
Ligand Species ◽  
Metal Ligand ◽  
Sulfur Donor

The interaction of silver ion with a range of mixed-donor macrocyclic ligands incorporating nitrogen, oxygen and/or sulfur donors has been investigated. Complementary calorimetric and n.m.r. studies in acetonitrile (and its deuterated derivative) were used to investigate the nature of the equilibria present as the metal/ ligand ratio was varied. In all systems the formation of a 1 : 1 species was observed, with a 1:2 (metal/ ligand ) species also being formed in the presence of excess ligand in the majority of cases. Enthalpies of formation for the various complexes have been determined. Stepwise stability constants for the respective [ AgL ]+ + L ↔ [AgL2]+ equilibria have been estimated from the calorimetric titration data, and the factors promoting the formation of the 1:2 species are discussed. The studies confirm the enhanced affinity of AgI for thioether donors over ether donors.

scholarly journals Assessment of labilities of metal complexes with the dynamic ion exchange technique

2019 ◽  
Vol 16 (3) ◽  
pp. 151
Author(s):  
Federico Quattrini ◽  
Josep Galceran ◽  
Carlos Rey-Castro ◽  
Jaume Puy ◽  
Claude Fortin
Keyword(s):  
Ion Exchange ◽  
Natural Waters ◽  
Breakthrough Curves ◽  
Short Exposure ◽  
Metal Bioavailability ◽  
Operation Conditions ◽  
The Impact ◽  
Free Metal ◽  
Metal Ligand ◽  
Exchange Technique

Environmental contextIn natural waters, the impact of metals on biota is modulated by their binding with ligands. Ion-exchange techniques can provide information about metal-ligand complexes in solution, which can be linked to metal bioavailability in natural waters. We investigate modelling approaches to interpreting data from ion-exchange experiments to help elucidate the contribution of a particular complex to the overall metal uptake. AbstractThe dynamic ion exchange technique (DIET) is proposed to provide speciation information, which can be used to establish links with metal bioavailability in natural waters. The experimental setup consists of a few milligrams of a sulfonic acid type ion exchange resin packed in a plastic microcolumn that is coupled to a peristaltic pump for a sample to interact with the resin which is subsequently eluted. The evolution of both the accumulated number of moles in the resin and the concentration of the effluent can provide information on the dissociation of different metal-ligand complexes when compared with the transport properties. This information can be converted into the lability degree of a given complex or the DIET concentration cDIET, which accounts for the labile fraction contributing to the metal accumulation by the resin column at the operation conditions. cDIET can be extended to columns containing chelating resins (such as those with Chelex) or to chromatography. A comprehensive modelling of the involved phenomena (such as diffusion, advection, reaction kinetics and electrostatic partitioning) leads to the quantitative interpretation of the accumulation time series (accumulation curves) or effluent evolution (breakthrough curves). Particularly simple analytical expressions can be used for short exposure times, when a (quasi) steady-state is attained. These models have been checked against the results from complexes of Cu and Ni with ligands, such as ethylenediamine, and ethylenediaminetetraacetic, iminodiacetic, glutamic, salicylic, malonic and malic acids, which yield complexes with contrasting charges. Caution is advised when estimating the free metal fraction from DIET measurements, as cDIET and the free metal concentration can be considered to be equal only in the case of extremely inert complexes.

The State of Metal Ions in Natural Waters

1984 ◽  
Vol 12 (4) ◽  
pp. 335-361 ◽  
Author(s):  
P. N. Linnik ◽  
B. I. Nabivanets
Keyword(s):  
Metal Ions ◽  
Natural Waters ◽  
The State

Selenium chemical speciation in natural waters: Protonation and complexation behavior of selenite and selenate in the presence of environmentally relevant cations

2011 ◽  
Vol 288 (1-2) ◽  
pp. 32-38 ◽  
Author(s):  
J. Torres ◽  
V. Pintos ◽  
L. Gonzatto ◽  
S. Domínguez ◽  
C. Kremer ◽  
...  
Keyword(s):  
Natural Waters ◽  
Chemical Speciation
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