Jaxon Dii Horne Posted February 27 Share Posted February 27 Hi-- I am trying to find some guidance. I am trying to convert/add an organic metal ion complexation WHAM Model VII database to GWB, but I am having difficulty doing this. I have read the essential guides, the manual, the book, and tutorials on converting databases to GWB format. I think my problem is that I do not really want to enter in all the data by hand, but can not quite figure out the format in which I should have the txt/sdat/tdat file in to allow the tedit program to import the dataset. It doesn't extensively explain how I would build a new database from scratch. My thoughts were to look at the HFO database that comes with GWB and then edit the text file to add in my data but that does not seem to be working. I would appreciate any help with this. Jaxon Dii Horne Quote Link to comment Share on other sites More sharing options...
Jia Wang Posted February 28 Share Posted February 28 Hello Jaxon, The TEdit application current accepts PhreeqC and EQ3/6 datasets for conversion to the GWB format. Are you trying to create a surface dataset or a thermodynamic dataset? Surface datasets in the GWB loads its aqueous species from a thermodynamic dataset. You can see which thermodynamic dataset it is using from the header block located on top of the sdat file. In general, I would recommend editing and creating new datasets with TEdit, especially if you are unfamiliar with the text file format. If you are still running into issues with this, please post the .tdat or .sdat file that you are having issues with so that we can take a closer look. If you can provide additional information regarding the dataset that you are trying to create, that will be helpful too. I think you will find Thermo Datasets in the GWB Reference Guide and Using TEdit in the GWB Essentials Guide very useful. More information regarding the types of surface complexation models and sorption models are located in section 2.6 in the GWB Essentials User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC Quote Link to comment Share on other sites More sharing options...
Jaxon Dii Horne Posted October 5 Author Share Posted October 5 Hi Jia- I was able to make some progress finally on the database. I have attached the .sdat and .tdat files that I have created. These are the work in progress I have a fulvic acid and humic acid database converted from thermo and mineteq database, and the surface complexation model for the humic acids. The problem that I have encountered is that ~90% of the humic acids (HA) should complex with the surface of the mineral goethite, and I get really small values, so I think I don't have the reaction setup correctly. Cheers, Jaxon Ha_REE1v1.sdat thermo_YREE_HA-FA.tdat Quote Link to comment Share on other sites More sharing options...
Jia Wang Posted October 6 Share Posted October 6 Hello Jaxon, Thank you for attaching the files you have been compiling. I am not really familiar with the WHAM models and their datasets but can give a couple of suggestions for what to check when creating new GWB datasets. Surface datasets in the GWB use minerals and aqueous species from a corresponding thermo dataset. For a two-layer type surface model, the surface reactions are tied to a specific mineral surface. The sorbing mineral designated in your surface dataset is Ha(s). If this is a dataset intended for modeling reactions on the Goethite mineral surface, the sorbing mineral should be that instead of Ha(s), as well as the surface area (m^2) available for complexing per gram needs to be given correctly for the correct mineral. In the GWB modeling program (e.g. SpecE8), you will need to include the mineral with the sorbing surface in the simulation, either by swapping it and setting it in equilibrium with the initial system, or in a program like React/X1t/X2t, you can set a kinetic mineral with a zero reaction rate, which would set an inert(not dissolving or precipitating) mineral. You can refer to section 7.2 Equilibrium models for more information on swapping in the GWB Essentials Guide. Information regarding kinetic minerals can be found in section 4 of the GWB Reaction Modeling guide. The program also carries the elemental composition of all species in the GWB program. I am not sure what would be appropriate here but looking at the names of your species, the basis surface site might include Ha(aq)? For example, a typical hydrous ferric oxide surface site can be represented as FeOH with 0 charge composed of 1 Fe, 1 O, and 1 H. I also noticed that Log K for all principal temperatures for the mineral Ha(s) is entered as 0. Is this correct? I just wanted to note that a value of "500" entered would be considered no data within a GWB dataset. In general, it would be good to double check that your Log Ks are entered correctly. Other things to check is whether you are employing the same activity model for calculating the activity coefficients of various species. The thermo dataset you attached uses the b-dot model, one of the expanded forms of the Debye-Huckel equation. Does the other software also calculate activity coefficients of species in the same method? For more information on various activity models accepted in the GWB, please see section 7.4 Activity coefficients in the GWB Essentials Guide. Hope this helps, Jia Quote Link to comment Share on other sites More sharing options...
Jia Wang Posted October 10 Share Posted October 10 Hello, I would just like to follow up that if you would like for someone to take a closer look at the issue of mismatched results, please provide full details regarding the model in the original software and the GWB input files that you are using to try and replicate those results. Thanks, Jia Quote Link to comment Share on other sites More sharing options...
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