Cation exchanger selectivity

Exchange of organic ammonium cations. Exchange selectivity of monovalent alkyl ammonium cations in montmorillonites (40-41) and octahedrally substituted synthetic clay minerals (laponite) increases with their chain length (42) and along the series... 

Teppen, B. J., and Aggarwal, V. (2007).Thermodynamics of organic cation exchange selectivity in smectites. Clays Clay Min. 55,119-130. 

Based on Reaction 4.33, the cation-exchange selectivity coefficient (ATCa Mg or KG) can be expressed as... 

TABLE 4.3. Cation Exchange Selectivity Coefficients for Homovalent (K-Na) and Heterovalent(K-Ca) Exchange... 

F. W. E. Strelow and H. Sondorp, Distribution coefficients and cation-exchange selectivities of elements with AG50W-X8 resins in perchloric acid, Talanta, 19,1113,1972. 

Cation Exchange Selectivity Coefficients for Nafion Polymers... 

The present investigation contributes to a better knowledge of the cation exchange selectivity series of phillipsite and chabazite [5]. The collected results are consistent with those of previous investigations, in which good selectivity for large cations and unselectivity for smaller cations were demonstrated by both zeolites [8],... 

Treatment of liquid wastes with zeolites is a very promising technique, especially for removal of ammonium and heavy metal ions fi om boA municipal and industrial wastewater (Pansini, 1996 Colella, 1999). Indeed, many natural and synthetic zeolites exhibit good ion exchange properties in terms of cation exchange selectivity and capacity for the main toxic and noxious cations. In addition, natural zeolites are readily available in many areas of the world at relatively low costs (Colella, 1999). 

Teppen, B. J., and D. M. MiUer. 2006. Hydration energy determines isovalent cation exchange selectivity by clay minerals. Soil Science Society of America Journal 70, no. 1 31-40. 

Results of models for the Tournemire shales are reported in Table 4. These models were based upon the mineralogical and CEC data presented in Tables 1 and 2 the calculated cation exchange selectivity coefficients and the concentrations of leachable Cl present in the rocks. Preliminary selectivity coefficients (Ac(Mg/Na) and Kc Ca./ Na) close to 3 and 4 respectively) have been derived from aqueous extraction experiments. They are in rather good agreement with literature data (Baeyens Bradbury 1994), and are mainly related to the illite and inter-stratified illite/smectite contents. The leachable Cl has been extracted with pure water at a liquid/solid ratio of 10mlg. It is clear that the Tournemire porewater cannot be definitively described with the data available. The porewater is of Na-Cl-(HCO ) type, with a low salinity, equivalent to a total dissolved... 

Helfferich, R, Cation exchanger selective for potassium ions. Zeitschrift fur Phys Chem 1956, 8, 265-283 (d) Parsons, J. S., Permselective membrane electrodes. Analytical applications. Anal Chem 1958, 30, 1262-1265. 

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