Dataset of surface reactions for gwb programs Dataset format: sep22 Surface type: Goethite Model type: three-layer Surface potential: n/a Surface capacitance: 0.60 0.20 (Specify values of C1 and C2 in F/m2) Thermo dataset: thermo.tdat * * Example of a triple-layer reaction dataset: NaCl sorption onto goethite. * * Based on data of Sahai and Sverjensky (1997). * * Reference: Sahai, N. and Sverjensky, D.A., 1997. Evaluation of internally consistent parameters * for the triple-layer model by the systematic analysis of oxide surface * titration data. Geochimica et Cosmochimica Acta, 61(14), pp.2801-2826. * * This dataset includes triple-layer model parameters for the goethite-NaCl system. * Reactions in GWB datasets are written in terms of dissociation reactions. The values of association reactions logKs are * therefore negated from their corresponding literature values. * * GWB releases 14.0 and later support bidentate and polydentate reactions according to * the stoichiometric, Davis-Leckie, Hiemstra-Van Riemsdijk, and Appelo-Postma conventions. * Refer to section "Polydentate sorption" in the GWB Essentials Guide. * * GWB releases 14.0 and later accept site density values in units of either "mol/mol mineral" * or "sites/nm2". -end- 1 basis species >FeOH charge= 0 mole wt.= 72.8543 g 3 elements in species 1.000 Fe 1.000 H 1.000 O -end- 1 sorbing minerals Goethite surface area= 86.0000 m2/g 1 sorption sites >FeOH site density= 16.4000 sites/nm2 -end- 4 surface species >FeOH2+ charge0= 1 chargeb= 0 mole wt.= 73.8622 g 2 species in reaction 1.000 >FeOH 1.000 H+ log K a= -6.3000 b= 0.0 >FeO- charge0= -1 chargeb= 0 mole wt.= 71.8464 g 2 species in reaction 1.000 >FeOH -1.000 H+ log K a= 11.9000 b= 0.0 >FeO-:Na+ charge0= -1 chargeb= 1 mole wt.= 94.8362 g 3 species in reaction 1.000 >FeOH 1.000 Na+ -1.000 H+ log K a= 9.5000 b= 0.0 >FeOH2+:Cl- charge0= 1 chargeb= -1 mole wt.= 109.3152 g 3 species in reaction 1.000 >FeOH 1.000 Cl- 1.000 H+ log K a= -8.7000 b= 0.0 -end-