Solubility and transport

An important result of the concepts discussed in this section and the preceding one is that precipitation and complexation reactions exert joint control over metal ion solubility and transport. Whereas precipitation can limit the dissolved concentration of a specific species (Me ), complexation reactions can allow the total dissolved concentration of that metal to be much higher. The balance between these two competing processes, taking into account kinetic and equilibrium effects, often determines how much metal is transported in solution between two sites. 

Barne.s, H.L. and Czamanske, G.K. (1967) Solubilities and transport of ore minerals. In Barnes, H.L. (ed.). Geochemistry of Hydrothermal Ore Deposits. New York Holt, Rinehart and Win.ston, pp. 334-381. Berndt, M.E., Seyfried, W.E. Jr. and Janeckey, D.R. (1989) Plagiocla.se and epidote buffering of cation ratios in midocean ridge hydrothermal fluids Experimental results in and near the supercritical region. Geochim. Cosmochim. Acta, 53, 2283-2300. 

A mechanism Is proposed by which water-insoluble plant lipids (sterols etc.) may act as allelochemicals via micelle formation with long-chain fatty acids. By this process plant lipid solubility and transport In the aqueous medium are enhanced. This might suggest a reevaluation of water-insoluble plant constituents such as sterols as potential allelopathic agents. 

McGowen S.L., Basta N.T., Brown G.O. Use of diammonium phosphate to reduce heavy metal solubility and transport in smelter-contaminated soil. J Environ Qual 2001 30 493-500. 

Application of pollutant chemodynamic models, which neglect the DHS phase, may result in inaccurate estimations of apparent solubility and transport parameters. The impact of a DHS solubility enhancement is most pronounced for the least water-soluble solutes. The affinity of a solute for a DHS is a function of the same properties, which drive a complex organic mixture(s) to sorb onto the stationary solid phase, namely bonding interactions and hydrophobicity. 

The third section focuses on the behavior of trace metals, with an emphasis on processes that control their solubility and transport. It includes a chapter on mercury cycling in softwater lakes and two chapters that examine the solubility and transport of trace metals in two very different environ-... 

Depth of anesthesia is determined by the concentration of anesthetic agent that reaches the brain. Brain concentration, in turn, depends on the solubility and transport of the anesthetic agent in the bloodstream and on its partial pressure in inhaled air. Anesthetic potency is usually expressed as a minimum alveolar concentration (MAC), defined as the percent concentration of anesthetic in inhaled air that results in anesthesia in 50% of patients. As shown in Table 9.6, nitrous oxide, N2O, is the least potent of the common anesthetics. Fewer than 50% of patients are immobilized by breathing an 80 20 mix of nitrous oxide and oxygen. Methoxyflurane is the most potent agent a partial pressure of only 1.2 mm Hg is sufficient to anesthetize 50% of patients, and a partial pressure of 1.4 mm Hg will anesthetize 95%. 

Binding of hydrophobic molecules by specific protein carriers appears to be a very efficient mechanism to increase both solubility and transport of these molecular messengers in a hydrophilic medium. OBPs and CSPs may represent a successful application of this principle. In particular, the molecular mechanisms of transport of hydrophobic molecules may be more ancient than that most ancient of senses, olfaction. The olfactory system may have developed to extract the hydrophobic odorants from the air environment and optimize their transport and delivery to sensory cells. 

Microbes can control the local geochemical environment of actinides and alfect their solubility and transport. Francis et al. (1991) report that oxidation is the predominant mechanism of dissolution of UO2 from uranium ores. The dominant oxidant is not molecular oxygen but Fe(III) produced by oxidation of Fe(II) in pyrite in the ore by the bacteria Thiobacillus ferroxidans. The Fe(III) oxidizes the UO2 to UOl. The rate of bacterial catalysis is a function of a number of environmental parameters including temperature, pH, TDS, fo2, and other factors important to microbial ecology. The oxidation rate of pyrite may be increased by five to six orders of magnitude due to the catalytic activity of microbes such as Thiobacillus ferroxidans (Abdelouas et al., 1999). 

Riess, J.G. Le Blanc, M. Solubility and transport phenomena in perfluorochemicals relevant to blood substitution... 

In a quenchometric sensing scheme, the best description of luminophore quenching depends on how the luminophore molecules are distributed within the host matrix, the quencher (02, in this case) solubility and transport properties, and the efficiency with which the quencher molecules can interact with the luminophore molecules within the host matrix. In the simplest scenario, identical luminescent molecules are distributed within an analyte-permeable host matrix in such a way that they are each equally accessible to the quencher molecules and the microenvironment surrounding each luminophore molecule is largely similar, described as ... 

Baumgartner, C.E. Solubility and transport of nickel (II) oxide cathodes in molten carbonate... 

Sulfates are water-soluble and transported with the riverine discharge to the ocean. The 804 content in marine water is 2.7 g/L. Taking into account for the whole volume of the Ocean, 1.2 x 10 tons of S or 3.7 x 10 tons of sulfates has been accumulated duriug Earth s geological history in the oceanic waters. 

An important modification of the dual-mode sorption model has been made by Koros and coworkers ( ), who have extended it to binary mixtures. These investigators have shown that the predictions of their extended model were in satisfactory agreement with sorption (solubility) and transport measurements. 

Thermodynamics of Solubility Mathematics of Diffusion Factors Affecting Solubility and Transport Crystallinity, Fillers, and Morphology Temperature and Transitions Penetrant Size... 

Table II. Solubility and Transport of Argon at 30 C in Four Structurally Similar Polymers...

Fifth, in the four-or-more-ring aromatic compounds, the nonalkylated species were more abundant than the alkylated species. This observation indicates a high-temperature source for these substances. Other explanations for the data, however, such as preferential solubilities and transports or environmental modifications, must be considered before the sources of the larger PAHs can be unequivocally determined. 

How does clay and organic matter content influence metal solubility and transport ... 

Rivin D, Kendrick CE, Gibson PW, Schneider NS (2001) Solubility and transport behavior of water and alcohols in Nafion. Polymer 42 623-635... 

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