Organic and inorganic ligands

In Section 8, the material on solubility constants has been doubled to 550 entries. Sections on proton transfer reactions, including some at various temperatures, formation constants of metal complexes with organic and inorganic ligands, buffer solutions of all types, reference electrodes, indicators, and electrode potentials are retained with some revisions. The material on conductances has been revised and expanded, particularly in the table on limiting equivalent ionic conductances. 

Both organic and inorganic ligands such as Cl and dissolved organic carbon (fulvie acid and carboxylic acids) decrease metal adsorption. In the arid soils with higher pH, folic acids increase the solubility of metals such as Cu and Zn. The interaction between the transition of heavy metals and silicate surfaces was reviewed by McBride (1991). 

Complexes of metals with organic and inorganic ligands which absorb in the visible region of the spectrum are of importance in quantitative analysis. Transitions giving rise to coloured complexes are of three types ... 

Since discovery of MCM-41 materials [1,2] many researchers have been concentrated on the improvement of their quality and properties by incorporating heteroatoms such as titanium [3-5], boron [6,7], vanadium [8], gallium [9], and recently lanthanides (mainly La and Ce) [10-13]. Incorporation of these elements into the MCM-41 structure influences its stability as well as adsorption and catalytic properties [13]. The presence of silanol groups on the surface of these mesoporous materials allows for bonding of organic and inorganic ligands [14-16]. 

After a brief introduction on terminology, this overview summarizes the experimental and theoretical modelling methods applied in trace metal speciation studies, emphasizing the dissolved fraction as defined by 0.95 pm filtration. The experimental approach comprises interactions with organic - and inorganic ligands, speciation schemes, biological experiments and interactions with particles and colloids. 

In aquatic ecosystems, complexation to organic and inorganic ligands and competition between toxic metals and Ca or Mg ions for biological adsorption sites reduce the actual amount of metal available for uptake by organisms. Chemical equilibrium models applicable to natural systems include RANDOM (Murray and Linder 1983 ... 

The protection of ecosystems, upon which our health and lives depend (J ), requires that we understand natural processes and develop the capability to predict the effect of changes, such as the addition of pollutants, on these ecosystems. The prediction of trace-element behavior in ecosystems requires a multicomponent model by which one can 1) calculate aqueous speciation of the trace elements among both natural organic and inorganic ligands ... 

A9.7.2.1.2.3 Complexation of metals to organic and inorganic ligands in test media and natural... 

Neutral organoarsenic compounds of the type R3ASO are widely used for extraction of uranium and other valuable elements from aqueous solutions The photoluminescence method has been applied to study the kinetics of formation of complexes of uranyl cations with organic and inorganic ligands ... 

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