Ternary Exchange Systems

Farmers often use NH4 and K salts as fertilizer sources. Even though applied NH4 has a short life span in agricultural soils (1-3 wk or more depending on rates of nitrification), the K-NH4-Ca exchange interaction controls the distribution of these 

In contrast to the PBCK for the K-NH4-Ca ternary exchange system (i.e., Equation 4.64) the PBCk for the K-Ca binary system, as CRK — CCRK, is described by Equation D in the previous boxed section Q/I Justification) which for convenience is shown below using KVI 

Equation 4.66 demonstrates that, when CRK approaches CCRK, PBCK will depend on the product of Kvl and CEC only. Assuming that CEC remains constant, the PBCK is dependent on KVI only. A high KVI indicates a high affinity for the K+ and manifests itself as an extremely high slope on the low portion (CRK — 0) of the Q/I plot. Furthermore, an increase in CRK would have a suppressing effect on PBCK (upper portion of Q/I plot) for a constant CEC and Kvl (Evangelou et ah, 1994). The same applies to the NH4-Ca exchange system. 

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Derive Eq. 5.37 and apply it to the experimental data in Table 5.3 for the ternary exchange system, Na-Ca-Mg-montmorillonite, to examine them for self-consistency. (Answer The mean value of the right side of Eq. 5.37 is 0.0029 + 0.0039.)... 

Na-K alloys are used in heat-exchange systems. Ternary alloy 10.1 at.% Na, 47.4 at.% K and 42.5 at.% Cs (L (Cs) + (K) + (CsNa2, KNa2)) probably has the lowest known melting point (—76°C) of all the metallic systems. Sodium amalgams, owing to their reducing properties, can be used in chemical synthesis processes. 

In the inter-alkali alloys, eutectic equilibria have been observed in a number of systems very low melting points have been determined for instance in the Rb-Na system (L (Rb) + (Na), at 82.5 at.% Rb and —4.5°C) and even lower melting temperatures have been observed in ternary systems. Binary sodium-potassium alloys, liquid at room temperature (at 25°C in a composition range of about 15-70 at.% Na, about 7-57 mass% Na), have a good thermal conductivity and a wide temperature range where they are liquid they may be used in heat-exchange systems. Their extremely high chemical reactivity must of course be taken into account. 

Few studies have appeared on ternary exchange kinetics, even though in most soil systems exchange processes involve three or more ions. Bajpai etal. (1974) studied Mn-Cs-Na, Ba-Mn-Na, and Sr-Mn-Cs exchange on a resin. Nernst-Planck equations were used to study the ternary systems, and when FD effects were included in the equations they described the data well. Other ternary kinetic studies were conducted by Wolfrum et al. (1983) and Plicka et al. (1984). 

Scheme 32 Reversible exchange of poly(butadien)yl chains (Ri and R2) between Nd and Al in the ternary catalyst systems NdV/DIBAH/EASC and NdV/TIBA/EASC (charge and ligands of Nd are omitted for clarity)...

As in Section 4.1, it is convenient to label exchanging ions with numerical indices in describing multicomponent ion exchange equilibria. The thermodynamic approach will be illustrated for a ternary cation exchange system (e.g., Na+, Mg2+, Ca2+), but the extension to an N-ary system is direct. This is evident, for example, in the Gibbs-Duhem equation for a ternary system ... 

It is important to emphasize that N-ary ion exchange relationships which do not enjoy thermodynamic status must be examined case by case to determine whether they can be built up from binary exchange data. For example, there is no reason to expect any conditional equilibrium constant Kijc to remain invariant under changes in the composition of an ion exchange system from binary to ternary. As another example, one can pose (he question as to whether binary exchange data for adsorbed species activity coefficients can be used, in... 

Michaels et al.50 53) reported the chemical and physical properties of the polyelectrolyte complex of NaSS-PVBMA. This complex is used as a membrane in various fields. Polyelectrolyte complexes prepared by casting homogeneous solutions of ternary-solvent systems mentioned above are transparent and amorphous. Dried polyelectrolyte complexes are hard materials whereas wetted ones are rubber-like or skin-like. The polyelectrolyte complex with an equimolar composition is neutral whereas that with a non-equimolar composition can display ion-exchange properties. The range of the water content depends on the excess of polycation or polyanion in the complex. 

Simple ternary reciprocal systems. The phase diagram of a simple ternary reciprocal system is schematically shown in Figure 3.35. In the systems of this type the exchange in the metathetical reaction between components takes place, for example p = q = r = s=l. 

Mirovsky Y, Tenne R, Cahen D, Sawatzky G, Polak M (1985) Ternary chalcogenide-based photoelectrochemical cells V. Surface Analyses of the CulnX2/aqueous polysulfide interface (X = S, Se) by X-ray photoelectron spectroscopy Absence of Se/S exchange in the CulnSe2/Sn system. J Electrochem Soc 132 1070-1076... 

As noted above, adsorption isotherms are largely derived empirically and give no information on the types of adsorption that may be involved. Scrivner and colleagues39 have developed an adsorption model for montmorillonite clay that can predict the exchange of binary and ternary ions in solution (two and three ions in the chemical system). This model would be more relevant for modeling the behavior of heavy metals that actively participate in ion-exchange reactions than for organics, in which physical adsorption is more important. 

Although the pure titanium-hydrogen system exhibits the normal isotope effect, many titanium alloys show the inverse effect. The exchange of pro-tium-tritium mixture with the hydrided phase of these alloys has demonstrated an inverse protium-tritium isotope effect in Ti-V, Ti-Mo, Ti-Cr, Ti-Mn, and the ternary alloy TiCrMn (1). On the other hand, Ti-Co, Ti-Fe, and Ti-Ni systems exhibit the normal isotope effect. Clearly much can be learned from a study of these systems. 

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