EES 6208 University of Washington Principles of Water Chemistry Paper

I’m studying and scarcity acceleration delay a Chemistry inquiry to acceleration me gather.

We are doing titrations and feeblenesss using the program denominated Minteq. My bigot has so dedicated the steps on how to work-out it.


Initial Step - Using MINTEQ, individualize the compound of the large stream soak by particularizeing the dedicated ALK and pH and exoteric the program to furnish that TOTCO3 and TOTH from the output below the “EQUILIBRATED MASS DISTRIBUTION” discretion. To do so:

1. Open MINTEQ

2. Set pH at agricultural at and penetrate 7.5

3. Go to the top bar and picked "PARAMETERS" and then "SPECIFY ALKALINITY". Here, picked the aces (meq/L) and penetrate the rate dedicated in the collection proposition. Note the disagreement in aces though! Finally, click OK


Second step

  1. Use Visual MINTEQ citeedly, and representing the individualized large stream chemical compound as the ‘baseline’ separation, ponder different additions of the wastesoak to the large stream soak to demonstrate the mixing narration that causes the pH to be 6.0. Use Visual MINTEQ titration instrument. Steps are as follows:
  • Start a new MINTEQ separation, and construct believing to delete the alkalinity rate penetrateed prior, as polite as the pH of 7.5
  • Now, set up the pH to fitted installed on majority balance
  • In the ingredient window, penetrate the tensions of TOTCO3 (as CO3-2) and TOTH (as H+) individualized overhead. That is:
  • Next, go to “Multi-Problem sweep” on the top bar of MINTEQ
  • Select titration / mixing delay a titrant delay defined compound and then set up the state of titration steps to some calculate (e.g. 41)
  • Going down the fence, below ingredient/species, picked H+
  • For the fashion (which fashion?) – picked activity
  • Then click ADD.
  • Go end on the top minority of the fence, and on the proper of the “titration/mixing” discretion pickeded prior, click on “Go to Titration Manager
  • On this fence, do the subjoined
    1. Volume (mL) of separation to titrate (e.g. 1000)
    2. Volume (mL) of titrant (e.g. 0.2)
    3. Concentration ace of titrant: mol/L
    4. Check the box for titration not to initiate plow remedy addition
    5. Define titrant compound by penetrateing the subjoined:
      • Enter molar conc. (e.g. mol/L), and then the ingredient (e.g. H+) and click on hinder and next.
      • Enter the remedy ingredient (e.g. SO4-2), cite the steps overhead as for H+, but pickeding sulfate as ingredient. For this collection, you get plug near.
    6. Click on “Save and go end to multi/sweep menu
    7. Then click on “Save and end
    8. Now end to the ocean menu – RUN MINTEQ
    9. From the output, picked “SELECTED SWEEP RESULTS” and in the consultation, the titration calculate selfsame to pH 6.0 or the closest to 6.0, if the exact pH is not shown
    10. Determine the body of titrant borrowed to earn the pH of 6
    11. Determine the feebleness factor


  • The dose of OH- that must be borrowed to induce the pH to 5.5 can be equated delay the extricate in TOTH betwixt the primal stipulation and the neutralized separation.
    1. Knowing TOTSO4, TOTFe, and pH, we can particularize the inputs
    2. Next, use the “Solid phases and exceptd kind” menu to except importance of the kind we desire to repudiate installed on recommendations in the collection proposition
    3. Run MINTEQ.
    4. The results should concede bigwig like
      • TOTH = 0.529M at pH 0.8 and
      • TOTH = -198M at pH 5.5
    5. The disagreement betwixt these two TOTH rates corresponds to the molar tension of OH- to be borrowed.
    6. Since 1 rampart of lime (Ca(OH)2) contributes 2 ramparts of OH-, the required lime dose to afford the scarcityed [OH-] would be equiponderant to half of the fitted tension in step-X
  • The titration deflexion can be generated using Visual MINTEQ by instructing the program to appraise the pH as a office of lime dose, resulting in the subjoined deflexion
      • Inputs: (SO4-2 = 0.4M, Fe+2 = 0.1M, Ca+2 = 0.
      • Excluded kind: CaSO4 and FeSO4
      • Ionic power agricultural at 0.1M