RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

Show Detailed Complexation Query Results


Surface Complex Formation Data:

Mineral: Goethite
Reference: S79
SCM Type: CC - Constant Capacitance
Ligand: PO4<3-> - phosphate
Site Type: »Fe-OH
Equation: »Fe-OH + PO4<3-> + 2 H<1+>  ⇔  »Fe-HPO4<1-> + H2O
LogK: 26.802        LogK°I=0 (Conversion to I = 0):   27.98         LogK2.31 nm−2 (SSD-normalized):   32.07
Experiment: Potentiometric Titration
Ionic Strength: 0.1 mol/L NaClO4
Temperature: 295.15 K
Solid/Liquid Ratio: 6.0 g/L
pH Range: 3.5-10
Ligand Concentration Range: 2E-4. 5E-4. 8E-4. 1E-3 mol/L
Fit Method: graphic extrapolation
Comment: cited in [SKS80], [SS87] and [SS80], SCM named \"ligand exchange model\", dependence on charge e^(F psi/R T); original reaction equation in the study: »Fe-OH + H3PO4 = »Fe-HPO4<1-> + H<1+> + H2O with logK = 5.1, formation constant in aqueous solution: PO4<3-> + 3H<1+> = H3PO4 logK = 21.702 [GFFGN03]
 
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