NICA-Donnan
Non-Ideal Competitive Adsorption + Donnan model. Describes metal binding to dissolved organic matter across pH, ionic strength, and concentration ranges. Generic parameters available for humic substances.
Acid-Base Data
Units: mol/L, mL, mL, -, g/L, mol/L
Constraints
Acid-Base Results
Carboxylic
Qmax1--
logK1--
p1--
Phenolic
Qmax2--
logK2--
p2--
Donnan
b--
Fit Quality
RMSE--
R²--
Theoretical Basis
- NICA: Non-Ideal Competitive Adsorption — describes heterogeneous binding on two site types (carboxylic, phenolic)
- Donnan: Electrostatic partitioning of ions between bulk solution and the DOM volume; parameterized by ion strength and b value
- Acid-base mode: Fits charge vs pH curves to derive intrinsic site parameters (Qmax, logK, p, b)
Key References
- Kinniburgh et al. (1999) NICA-Donnan model for metal-DOM binding.
- Milne et al. (2003) Generic NICA-Donnan parameters for humic substances.
- Tipping (1998) WHAM/Model VI — background for NICA development.