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Journal of Environmental Quality Abstract - Ground Water Quality

A Transport Model with Coupled Ternary Exchange and Chemisorption Retention for Hydrazinium Cations


This article in JEQ

  1. Vol. 30 No. 5, p. 1540-1548
    Received: Oct 27, 2000

    * Corresponding author(s): rsm@gnv.ifas.ufl.edu
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  1. R. S. Mansell *a,
  2. S. A. Blooma and
  3. W. C. Downsb
  1. a Soil & Water Science, P.O. Box 110290, 2169 McCarty Hall, Univ. of Florida, Gainesville, FL 32611-0290
    b Civil and Environmental Engineering, Brigham Young Univ., 368 Clyde Building, Provo, UT 84602


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.

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Copyright © 2001. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.30:1540–1548.