KDanny

Hello, I'm trying to model the kinetic diffuse double layer sorption of uranium to geothite. I'm unsure on how to create the V.10 REACT model. I have followed the tutorial "How do I simulate sorption kinetics?" on the GWB website and still have questions. The following error messages pops up for various inputs: 1. Kinetic -> Sorbed species: >Fe-OH -- Error: Kinetic reactant >Fe-OH is a surface site, not a complex. 2. Kinetic -> All other sorbed species [Model freezes and I have to kill it] What can I do to correct the errors? Do I need to add each individual sorbed species in the "reactants" tab to accurately model sorption kinetics? I have attached the REACT file and the Sorption file. I would like to attach the thermodynamic database, but it exceeds the max single file size. Thank you, KDanny W-812-01_29Sep2000_KD08182015.rea DDL_U_Goethite.sdat

Hello, I’m trying to model precipitation of the uranium-bearing mineral, Swartzite (CaMg(UO2)(CO3)3•12(H2O)), from solution. When I equilibrate my ground water chemistry of interest using REACT and X1T, Swartzite is the only uranium-bearing mineral to be supersaturated (SI>0 [sI=0.45]). I’m using an updated thermodynamic database, that includes uranium data determined after the discovery of Ca2UO2(CO3)30 CaUO2(CO3)3-2and MgUO2(CO3)3-2 complexes by Bernhard in 1996. I can’t find appropriate kinetic rate constants for the precipitation and dissolution of Swartzite to include in my REACT and X1T models. I plan to include rate constants of an alternate uranium-bearing mineral in place of Swartzite, such as Schoepite or Rutherfordine if no data are available. However, such substitution will render my output a gross approximation. Has anyone determined or located reliable kinetic rate constants for Swartzite while modeling uranium mineral saturation? Has anyone been unable to find kinetic rate constants for a mineral, and ended up substituting in a similar mineral? Any help would be useful. Thanks. GWB_U_02172012.dat