Ion exchange multicomponent

FIG. 16"44 Multicomponent ion-exchange process for chromate recovery from plating rinse water. Adaptedfrom Rhom Haas with peimission.)... 

In a multicomponent ion exchange system, the reactions between exchanging ions still can be expressed as in Eqs. 5.1 and 5.2, which are binary processes, but the description of exchanger composition in terms of mole or charge fractions requires a generalization of expressions like Eq. 5.12 ... 

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 ... 

W. J. Brignal, A. K. Gupta, and M. Streat, Representation and Interpretation of Multicomponent Ion Exchange Equilibrium , in... 

Frey, D. D., Prediction of Liquid Phase Mass Transfer Coefficients in Multicomponent Ion Exchange Comparison of Matrix, Film-Model, and Effective Diffusivity Methods, Chem. Eng. Commun., 41, 273-293 (1986). 

Klein, G., D. Tondeur, and T. Venneulen, Multicomponent ion exchange in fixed beds,... 

LL Homg. Reaction mechanisms and chromatographic behavior of polyprotic acid anions in multicomponent ion exchange, PhD dissertation. University of Houston, Houston, Texas, 1983. 

The theoretical treatment of multicomponent ion exchange is quite complex, especially if it involves species of different valency. The treatment of ion-exchange equilibria involving only ions of the same valence is quite straightforward since it can be assumed that the selectivity coefficient or separation factor is constant over the complete range of ionic concentration. 

Appelo, C.A.X (1996). Multicomponent ion exchange and chromatography in natural systems. In Reactive Transport m Porous Media, eds. lichtner, PC., Steefel, C.I. Mineralogical Society of America, Washington D.C., pp. 193-227. 

Yeh. Y.T.. and Yang, R.T.. Diffusion in zeolites containing mixed cations, AlChE J 35(10), 1659-1666 (1989). Yu, Q.. and Wang, N.H.L.. Computer simulations of dynamics of multicomponent ion exchange and adsorption in fixed beds Gradient-directed moving finite element method, Comput. Chem. Eng., 13(8), 915-926 (1989). 

---