Isotherm Calculations


These data make sense; add more carbon to adsorb more dye and less is left in solution. We know the starting concentration of dye (1.768 from the assay that is not exactly the same as what was weighed out or 1.772, that is why we need controls). This is 1.768 g/L, but we had 100 ml. Thus 0.1768 g was added to each flask. Subtracting what was found at the end of the run from the amount at the start tells how much was adsorbed. This is divided by the grams of carbon to get the loading in grams of dye adsorbed per gram of carbon. Our calculations give this table:
Flask #    Grams of Carbon   Concentration of Dye  Loading on Carbon
  1                 0                     1.768 g/L            0    g/g
  2                 0.58                  1.416                0.0601
  3                 1.288                 1.062                0.0548
  4                 2.21                  0.711                0.0478
  5                 3.71                  0.419                0.0364
  6                 5.26                  0.178                0.0302
  7                 9.81                  0.042                0.0176
In our table we have the loading and the concentration of dye in equilibrium with that loading. These are the numbers needed to plot the isotherm.

Graph of Data

Home page for adsorption

Done

 Last update 10-Jan-95