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amnk

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About amnk

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  1. Dear Brian, How are you? I hope that you are doing very well. I am writing to you because I need your help with GWB. First of all, let me briefly describe my experiment. I have done column percolation tests using natural contaminated soil. I packed the contaminated soil (mainly with heavy metals) in a 5 cm diameter and 30 cm height acrylic column and permeated it with CaCl2 solution 1 mM at a flow rate of 12 mL/h (the flow direction is from bottom to top). I collected around 15 samples (leachate) within 3-month period and analyzed them by ICP and IC (ion chromatography). I input all leachate results in the GSS datasheet and would like to make solubility, speciation and transport modeling. I have the following questions: 1. In the GSS datasheet is there any place where I can input the TOC (total organic carbon) or DOC (dissolved organic carbon)? 2. In the GSS, how can I input Mo concentration? I know that there is no Mo information in the "thermo.dat", so, I changed it to "thermo.com.v8.r6t", but I am still not able to add Mo (I can't find it in "+analyte" > "basic species"). Did I do something wrong? 3. Do I have to know the specie of elements in advance? For example, from ICP analysis, I got the results of total Fe. In GSS, can I choose for example "Fe+++" and then choose the unit "mg/L (as Fe)" and solve the problem of choosing between "Fe++" and "Fe+++"? Another example is regarding B concentration, can I choose the specie "B(OH)3" and then select the unit "mg/L (as B)". One more example is "AsO4--", I think this is the only specie included in "thermo.dat", so I chose it and set as "mg/L (as As)". Is that the correct way to input the data in GSS or should I know the accurate specie since the beginning? 4. Regarding Xt1 transport, I would like to simulate/model the release of elements such as As, Pb, B, etc. and then plot or add the results I obtained from experiments. I have the following questions about what to input in each section: a. "Initial" section: should I input the mineral composition or elemental composition of the soil and the concentration of the permeating solution (CaCl2)? b. "Reactants" section: Should I input the mineral composition of the soil? c. "Inlet" section: Should I input the concentration of the permeating solution (CaCl2)? d. "Domain" section: Do you recommend me to use "linear" type or "spherical" (r1 = r2)? e. "Medium" section: Do I input the diffusion coefficient of the element, the porosity of the soil and the dispersivity of the element I am monitoring? I am very sorry for asking so many questions. Thank you very much in advance for your help. Angelica
  2. Dear Brian, I am writing to you to get some suggestions regarding a fitting that I would like to do. I have performed column tests and measured change of pH, EC, ORP, TOC, cation and anion concentrations with time. I would also like to plot metal results in pH-Eh graphs. I would like to know which applications I should use to do so. First of all, I think that I have to input the results I obtained from column experiments in the GSS sheet? In the handouts I received during the course (page 112) there is a fitting of column test results. I would like to do something similar so, I would be very grateful if you could give me some suggestions. Thank you very much for your kind attention. Angelica
  3. amnk

    Mercury Eh-pH diagram

    Hi Brian, Thank you very much for your assistance. I will try it and report in this forum whether I could adjust the figure or not. Thank you, Angelica
  4. amnk

    Mercury Eh-pH diagram

    Dear Brian, Thank you very much for your guidance. You can't imagine how much you are helping me. I downloaded the file without any problem (thank you for editing the data-file for me) and then added the H2(aq) and H2(g) from Thermo.tdat. It worked very well and now I have the figure almost done. The only small thing that I noticed different from the original is the Hg(aq) section. In the original data, there are two sections with Hg(aq), the big one (in the center) and the small one (in the left south). However, in the figure I got from GWB I can only see the one in the center. I think it is probably because of the difference in thermodynamic data between the minteq database and the data in the Table. All the best, Angelica
  5. amnk

    Mercury Eh-pH diagram

    Dear Brian, Thank you very much for your reply. I could successfully add ethanol in the database. Besides, I could add the reaction Hg(l) = Hg(aq) thanks to your suggestion. I have a question regarding the addition of H2(aq) and H2(g) reactions from thermo.tdat to thermo_minteq.tdat. I copied and pasted both reactions, for H2(aq) and then for H2(g). However, when I go to Act2 > File > Open > Thermo Data > thermo_minteq_Hg (the one that contains the H2(aq) and H2(g)) a series of errors appear: "reaction mass imbalance for Hg(OH)2 = -235 Reaction = Hg(OH)2" "reaction mass imbalance for Sn(OH)2 = -153 Reaction = Sn(OH)2" "reaction mass imbalance for Tl(OH)3 = -255 Reaction = Tl(OH)3" "reaction mass imbalance for Hg(OH)2 = -235 Reaction = Hg(OH)2" "Exit: Act2 stop: couple_rxns: bad rxn Act2 is ending" Then, the software closes. I was checking the data for Hg(OH)2, Sn(OH)2, etc., but I couldn't find the mistake. I hope that you can give me some suggestions to solve this. Thank you very much in advance. Angelica
  6. amnk

    Mercury Eh-pH diagram

    Hi Brian, Thank you very much for all the information you provided. I reverted to the original datasets, thank you for the link. You are right, this time, I should just consider the species involved. I added methanol in the "Basis species" section of the "Thermo_Hg.tdat" dataset that I created. After writing the name (CH3OH), charge (0), Ion size (4.4 A) and mole weight (32.04) and pressing Apply, an error saying "Mole weight is not balanced. / Entered: 32.04 Calculated:0 / Would you like to use the calculated value?" Is it OK to choose "No", right? It will not affect further results? I have another question. I could not include the following reactions into the "Thermo_Hg.tdat" dataset: a. Hg (l) = Hg(aq) b. HgS + S-- = HgS2-- c. CH3HgCl (l) = CH3HgCl (aq) d. CH3HgCl = CH3Hg+ + Cl- Do I have to look for the formation equation of these species? Do you have any recommendation/hint on how to add them? Also, I would like to try input H2(g) data into Thermo _minteq.tdat I tried copying from the Thermo.tdat, but it was not possible (an error message appeared). I think I have to manually input the following reactions, right? 2H2O + 2e- = H2(g) + 2 OH- 2H+ + 2e- = H2(g) Thank you very much in advance for your help. Angelica
  7. amnk

    Mercury Eh-pH diagram

    Hi Brian, Thank you very much for your help. I followed your suggestions and I am getting closer to the diagram. I have some questions about the addition of reaction into the Thermo Data. I tried to add the reactions showed in Table 19 (please refer to the USGS document) into the thermo.tdat, but I got some error messages: 1) For instance, I could not input the following reaction: Hg(CH3)2 + H2O = CH4 + CH3(OH) + Hg I could not find CH3OH or methanol in the list. Is there any place where I can add CH3OH, maybe typing it? Or do I add CO + 2H2, instead? I had the same problem writing the following reaction: C6H5Hg+ + OH- = C6H5HgOH I had also an inconvenience with the reaction: Hg(NH3)4++ = Hg++ + 4NH3 The software automatically changed this equation to: Hg(NH3)4++ + 4H+ = Hg++ + 4HN4+ Of course the K was also automatically recalculated by the software. But then, a message saying "Reaction is not charge balanced. Verify species coefficients and charge of entry" appeared. 2) TEdit gives the option to complete Log K's at different temperatures. Table 19 shows only K values at 25 degree. If there is no information about K's at other temperatures, should I leave the space empty? By default, the software introduces the number 999984... I deleted all of these values. 3) In Act2, when I used the modified thermo.tdat, a warning saying "reaction charge imbalance for Hg(NH3)4++ = Reaction = Hg(NH3)4++ + 4*H+ + 4*NH4+" appears. After pressing OK several times, the applications closes. I assume there are problems with the equations I input. Please find two documents attached in the following link regarding the input of reactions and the error message in Act2: http://tinyurl.com/px4mqd4 Thank you very much in advance for your assistance. Angelica
  8. Hi, I would like to reproduce Figure 5 (page 22, Eh-pH graph of Hg) of the file that you can find in the link below: http://pubs.usgs.gov/pp/0713/report.pdf Briefly, I would like to tell about my communication with Brian by e-mail before joining this Forum. To draw the Eh-pH graph, I input the concentration of Hg++, Cl- and SO4-- using Act2 (see the document attached Trial1). The figures only showed 3 phases. To solve the problem and, thanks to Brian's help, first, I modified the units from ppm to molal using GSS (see the document attached Unit conversion). In GSS, I input the ppm values reported in the USGS file in mg/L because I assumed that it was the aqueous concentration... mg/kg input gives a slightly different results... In this part, I would like to know if I should have added other analytes in the system because there are no cations that can balance the anions? Moving into Act2, I input the new concentrations (see the document attached Trial2). Also, as suggested by Brian, I switched to different Thermo Data to see which one was better for this case. It appears that thermo_minteq has the largest amount of Hg species, so I chose it. In the Basis (diagram species section) of Act2, I chose Hg(OH)2, but I do not know whether I should have done Hg(aq) <> Hg(OH)2? Once I input the new values into an Act2 sheet, I got an error message saying "Reaction for H2(g) is missing; can not plot water limit". I do not know how to solve this problem. Is it related to the water activity? I left water activity in 1, but I am not sure about it. How do I input H2 in the system? Is it in the "in the presence of" section? I am very sorry for the basic questions I am making. Thank you very much for your attention. Angelica Trial1.ac2 Unit conversion.gss Trial2.ac2 Error message.docx
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