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some question of React and X1T units


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Hi,everyone

I am making the model of Reactive transport model include desorbing Copper ions from Ferrihydrite in sediments. 

First, I made the sediments which contains Ferrihydrite in React, sorbing Copper ions and check the result amounts of adsorped Cu ions.

after pick up the result from entire (include the fluids),Copy to X1T's initial, or use the same as React's basis in it, after making reactive transport.

But I want to confirm.

1.  When pick up the data, the only unit is mol. I think that means the amounts of ions(Minerals) in the Bulk Volume of the React script, so I can't use that in X1T initial except when X1T's node volume is equal to React's bulk volume. I don't want change node volume, I made the model  use the same as React's basis. is it correct?

2. I make the model of React, first I use wt%. Wt% is not compare mineral weight but water weight,so there is less mineral than using Volume%, is it true?

3 When I check the result of React script, amounts of sorbed Copper is wrote  1.033e+04mg/kg. this kg means water,not mineral weight.

there is only 1.0701kg water, so sorbed all ions is almost 1.105e+04mg, this calculate is correct?

4 in X1t, I want to show the results of an experiment in which we put 20 millilitres of solution per day into a column with a base area of 7.55 square centimetres.

Flow fluid is (20/7.55=)2.649cm/day I setted. is it true? If I have to set something about diffusion, I want to know.

 

Best,wishes.

Arata

 

 

Column_Fh_0.5.x1t FhVol%.rea FeOH+thermodemn.sdat thermoddemV1.tdat

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Hello Arata,

Thank you for posting your input files along with your surface and thermo datasets. I couldn't run your input files exactly as they are because of two surface datasets (SO4.sdat and Shimazui.sdat) I don't have. Here are some answers that I hope are helpful:

1. You are correct that the pickup command only retrieves the component concentration in moles. Typically in React, you would set the initial composition of your fluid (as the Basis) and then set a desired reaction path to alter your initial composition (e.g. titrating in reactants, sliding temperature, kinetic reactions, etc). You can use then use pickup feature as an easy way to set up the result from a simulation as a new starting point or as a set of reactants. It seems like you already have the starting composition of your experiment, since no reaction was prescribed to change the composition in your React simulation. In that case you can just use the same constraints as your Initial composition in X1t. 

If you would like to use React to create a new fluid composition for your starting point with the same volume as a node in your Reactive transport model, you can scale the bulk volume of your React simulation in the Medium pane to the same as one node volume in X1t. You can calculate the volume for one node from the Medium pane in X1t. For more information on configuring React reaction paths, please refer to section 3 Tracing reaction paths in the GWB Reaction Modeling User Guide.

2. Weight percent is the mass of mineral per mass solution times 100. Volume percent is the volume of mineral per system's bulk volume times 100. 

3. In the React output text file, the sorbed concentration for each component is given in terms of milligram per kilogram solution. You can multiple the concentration by the solution mass given near the top of the output file to get the total mass sorbed. Alternatively, you can also render your result in Gtplot and change the unit to 'mg'. 

4. Yes, the flow is set as volumetric discharge in GWB reactive transport applications. The unit is volume per cross sectional area per time. You can set the diffusion coefficient in the Medium tab in X1t. By default, the diffusion coefficient is set to 1e-6 cm/s. Please see section 3.3 Mass Transport in the Reactive Transport Modeling User Guide for more details. 

Best regards,
Jia Wang
Aqueous Solutions LLC

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