A Transport Model with Coupled Ternary Exchange and Chemisorption Retention for Hydrazinium Cations
- R. S. Mansell *a,
- S. A. Blooma and
- W. C. Downsb
A numerical model was developed to describe the fate and transport of hydrazinium N2H+ 5 and competing Ca2+ and H+ cations applied in acidic solutions to columns of Ca2+/H+–saturated sandy soil during steady saturated flow conditions. Instantaneous ternary H+–Ca2+–N2H+ 5 cation exchange using the Gaines–Thomas approach was combined with second-order, irreversible, kinetic chemisorption of exchange-phase N2H+ 5 ions as major retention mechanisms for N2H+ 5 Exchange-mediated chemisorption is assumed to occur as chemical binding of N2H+ 5 ions located on carboxyl-group exchange sites to nearby carbonyl groups, consequently decreasing the effective soil cation exchange capacity (CEC). Comparison of simulated and observed breakthrough curves (BTCs) for concentrations of N2H+ 5 and Ca2+ ions in column effluent was used in model evaluation. The cation transport model with cation exchange coupled with exchange-mediated chemisorption provided a valid first approximation for N2H+ 5 transport.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2001. Published in J. Environ. Qual.30:1540–1548.