Properties of the solid phase

Equation 1 implies that solubility is independent of solvent type, and is only a function of the equilibrium temperature and characteristic properties of the solid phase. In real systems the effect of non-ideality in the liquid phase can significantly impact the solubility. This effect can be correlated using an activity coefficient (y) to account for the non-ideal liquid phase interactions between the dissolved solute and solvent molecules. Eq. 1. then becomes [7,8] ... 

There is evidence that mixed Fe(II)-Fe(III) hydroxides are formed. These can be produced easily in vitro by partial oxidation of pure Fe(II) hydroxy salts and they have some of the observed properties of the solid phase Fe(II) found in reduced soils, including the grayish-green colours characteristic of reducing conditions in soils. This material is green rust and has the general formula Fe(II)6Fe(III)2(OH)i8 with Al + partly substituted for Fe + and Cl, S04 and C03 substituted for OH . 

The solid phase of the subsurface is a porous medium composed of a mixture of inorganic and organic natural materials in various stages of development. The surface area and the surface (chemical) properties of the solid phase are major factors that control the behavior of chemicals. 

Soil organic matter is found wherever organic matter is decomposed, mainly in the near surface. However soil organic matter may also be transported as suspended particles into deeper layers of the vadose zone or via surface- and groundwaterforming sediments. Although these components form a minor part of the total solid phase, they are of major importance in defining the surface properties of the solid phase and have a great impact on the chemical behavior. 

Dissolution and precipitation in the subsurface are controlled by the properties of the solid phases, by the chemistry of infiltrating water, by the presence of a gas phase, and by environmental conditions (e.g., temperature, pressure, microbiological activity). Rainwater, for example, may affect mineral dissolution paths differently than groundwater, due to different solution chemistry. When water comes in contact with a solid surface, a simultaneous process of weathering and dissolution may occur under favorable conditions. Dissolution of a mineral continues until equilibrium concentrations are reached in the solution (between solid and liquid phases) or until all the minerals are consumed. 

In the subsurface, kerosene volatilization is controlled by the physical and chemical properties of the solid phase and by the water content. Porosity is a major factor in defining the volatilization process. Galin et al. (1990) reported an experiment where neat kerosene at the saturation retention value was recovered from coarse, medium, and fine sands after 1, 5, and 14 days of incubation. The porosity of the sands decreased from coarse to fine. Figure 8.9 presents gas chromatographs obtained after kerosene volatilization. Note the loss of the more volatile hydrocarbons by evaporation in all sands 14 days after application and the lack of resemblance to the original kerosene. It is clear that the pore size of the sands affected the chemical composition of the remaining kerosene. For example, the fractions disap-... 

As mentioned previously, the retention of contaminants on geosorbents may occur by surface adsorption on or into the coUoid fraction of the solid phase and by physical retention as hquid ganglia or as precipitates into the porous media. The type of retention is defined by the properties of the solid phase and the contaminants as well as by the composition of the subsurface water solution and the ambient temperature. 

Using an analysis similar to that for the energy balance of the gas and after assuming constant physical properties of the solid phase,... 

The depression of the Na20/Al203 ratio during aging to proximately unity (probably caused by the loss of hydroxyl groups) was found only in the calculated composition of the solid phase. This was not found analytically after washing the solid phase with water (the result of experiment Gz, Table I, was the only exception). It seems, therefore, that the composition of washed solid phase does not correspond to the properties of the solid phase in the hydrogel. 

When the gas-solid flow in a multiphase system is dominated by the interparticle collisions, the stresses and other dynamic properties of the solid phase can be postulated to be analogous to those of gas molecules. Thus, the kinetic theory of gases is adopted in the modeling of dense gas-solid flows. In this model, it is assumed that collision among particles is the only mechanism for the transport of mass, momentum, and energy of the particles. The energy dissipation due to inelastic collisions is included in the model despite the elastic collision condition dictated by the theory. 

It would have been difficult to find these kinds of relations with inorganic materials proper. The organic molecule is unique in that its physical properties may be changed in a continuous way by small modifications in its structure or by complexation with different metal ions. Another advantage is the fact that solid state effects are of smaller importance, and catalytic properties of the solid phase may be compared with physical properties in solution. In particular an extended jr-electron system works as a catalytic entity in itself, irrespective of whether it is surrounded by other molecules of its kind (solid phase) or solvating molecules (solutions). 

Previous books in this area typically focus on selected aspects of the subject, such as the properties of the solid phase, or the interactions of selected substances with soil/rock. This book comprehensively treats the soil-liquid-interface system. Drawn chiefly from the authors years of research at the Isotope Laboratory in the Department of Colloid and Environmental Chemistry at the University of Debrecen in Hungary, this book discusses chemical reactions on the surfaces/interfaces of soils and rocks examines the role of these processes in environmental, colloid and geochemistry and explores the effects on agricultural, environmental and industrial applications. 

In this book, the processes at solid/liquid interfaces of soil and rock, in most cases under environmental conditions, will be discussed. A scientifically correct description of interfacial processes requires the study of the properties of solid and liquid phases and the interface, as well as the interactions of these phases. Previous books typically focused on selected aspects of the subject, such as, for example, the properties of the solid phase or the interactions of selected substances such as heavy metal ions with soil/rock. We intend to present a comprehensive treatment of the soil-liquid-interface system, emphasizing the importance of the chemical species produced in a geological material/solution/interface interaction. We recommend the book to all chemists, geologists, and soil scientists working in interfacial, environmental, and soil sciences. 

Internal motions are accounted for by Morse functions with parameters optimized to reproduce second virial coefficient and some properties of the solid phase. 

As cein be seen from the table, melting points of molecules with an even number of carbon atoms are relatively higher than those with odd ones. However, for the Increase of the surface tension with no even-odd irregularity is found. From this observation it can be inferred that the -irregularity must be a property of the solid phase (say, the packing of the parafim in a lattice). 

Authors indicated that as the descriptors in Eq.(36) refer to particular properties of the solutes, the coefficients in the equation will correspond to specific properties of the solid phase as follows r - refers to the ability of the phase to interact with solute ir- and n-electron pairs s to the phase dipolarity/polarisability a to the phase hydrogen-bond basicity b to the phase acidity, and 1 to the phase lipophilicity. Analysis of these coefficients lead authors to the statement that solute dipolarity/polarisability, hydrogen-bond acidity, and general dispersion interactions influenced adsorption. The examined fullerene was weakly polarisable and had some hydrogen-bond basicity. 

It is well known that the water content of the reaction medium (i.e., the solvent and solid enzyme-containing phase) has a strong impact on nonaqueous enzymology. Moreover, for a given reaction, enzyme preparation, and medium composition, there is an optimal water content for maximizing the enzyme activity, or the initial rate of reaction. The optimal value is a strong function of the presence and concentration of substrates, and properties of the solid phase. Moreover, the enzyme, immobilization matrix, and continuous phase all compete for adsorption/retention of water molecules. Polar solvents are known to strip away water molecules from solid-phase enzymes. ... 

As mentioned in Section 3.7.1.2, there is a considerable scatter of solubility product values obtained in the molten KCl-NaCl eutectic using different methods of solubility determination. This disagreement in the solubility parameters may be explained by differences in the sizes of oxide particles whose solubility is to be determined. The difference in size causes the scatter of the solubility data according to the Ostwald-Freundlich equation and the employment of the isothermal saturation method, which implies the use of commercial powders (often pressed and sintered), leads to values which are considerably lower than those obtained by the potentiometric titration technique where the metal-oxides are formed in situ. Owing to this fact, the regularities connected with the effect of physico-chemical parameters of the oxides or the oxide cations should be derived only from solubility data obtained under the same or similar experimental conditions. However, this does not concern the dissociation constants of the oxides, since homogeneous acid-base equilibria are not sensitive to the properties of the solid phase of... 

Perhaps the most varied combinations occur in solid-liquid systems because of the variety of properties possessed by the solid phase. The most obvious property of the solid phase to affect surfactant adsorption is the hydrophilic or hydrophobic... 

The variability in hydrophobicity and other properties of the solid phase and in concentration of the ionic species involved will make little sense for elucidations of more general validity. The heterogeneous nature of the adsorbing phase, most often Cg or Ci8 bonded silica, contributes to the complexity of the systems. Whatever approach is being used it must be emphasized that ion pairs are not fixed complexes in solution and even less on a surface. They represent a dynamic equilibrium in which the solute ion is transported or retained by the aid of the counterion, and electrostatic, hydrophobic, and other interaction provide overall electroneutrality. In this context it should be made clear that although the treatment so far has dealt with HA as solute ion and X as cormterion, the considerations made are as valid for the opposite system with X as ionic solute and HA as counterion in the mobile aqueous phase. 

The common characteristic of the various HPLC techniques is the reliance on small differences in the strength of interactions between species in the mobile (liquid) phase and the solid material that accomplishes phase transfer. Outside of extraction chromatography, few solid-liquid separation procedures for lanthanides derive their selectivity from the properties of the solid-phase material. For most HPLC separations of the lanthanides. 

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