RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

Show Detailed Complexation Query Results


Surface Complex Formation Data:

Mineral: Ferrihydrite
Reference: DPW02
SCM Type: DDL - Diffuse Double Layer
Ligand: UO2<2+> - uranyl(VI)
Site Type: »Fe(w)-OH
Equation: »Fe(w)-OH + UO2<2+> + CO3<2->  ⇔  »Fe(w)-O2-UO2CO3<2-> + 2 H<1+>
LogK: -0.417        LogK°I=0 (Conversion to I = 0):   0.23         LogK2.31 nm−2 (SSD-normalized):   1.31
Experiment: Mean of Different Sources
Ionic Strength: 0.1 mol/L
Fit Method: FITEQL
Comment: TAO extract of W1 sample dissolved 0.88 mg Fe/g sample [PSDW92], assumption that was derived from a poorly crystalline iron oxide phase similar to ferrihydrite, calculated U sorption less than the observed experimentally for W1 sample, although predicted adsorption by ferrihydrite near pH 6 was significant; original reaction equation in the study: »Fe(w)-(OH)2 + UO2<2+> + H2CO3 = »Fe(w)-O2-UO2CO3<2-> + 4 H<1+> with logK = -17.10, formation constant in aqueous solution: H2CO3 = CO3<2-> + 2H<1+> logK = 16.683 [DK01]
 
1 data sets were retrieved