User:Andrew K Farag/Notebook/CHEM-581/2014/10/01

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Objective

Alicia and Madeleine and Becky, Eleni and Melvin's group worked on determining fluorophore concentration. My group and Jake, James and Mary worked on diffusion. The groups working on diffusion were given priority to use the UV Vis because the diffusion results were time sensitive. The diffusion results will determine the speed in which the polymer films can clean the malachite green out of the water. My group (AMT) set up an experiment using the PVA film, while MJJ's group used the PVA with Clay film for their experiment.

Description

Diffusion

  1. One group will use a PVA film
  2. The other group will use a PVA/clay film
  3. Set the film between the two chambers
  4. Add liquid to each chamber
    1. One chamber gets water
    2. The other chamber gets 20ppm Malachite green
  5. Withdraw 200uL from each chamber at the 5 minute mark and place in their own eppy tube
    1. NOTE: I want the groups to coordinate so that their 5 minutes don't overlap with one another.
    2. NOTE: You'll want to use a small volume cuvette
    3. NOTE: You'll also want a 0minute measurement for each.
    4. NOTE: You'll likely have to dilute the sample from your chamber with the 20ppm. So, when you return the sample, only return the non-diluted sample.
  6. Measure the UV-Vis spectrum for both samples. Return each to the chamber it originally came from
  7. Take measurements at the following times
    1. 15 minutes
    2. 30 minutes
    3. 1 hour
    4. 2 hours
    5. right before you leave lab
    6. It would be great if someone could stop by on Thursday to take a measurement then.
    7. You'll be taking measurements on Friday too.
  8. During each of this, it would be best to start working up the data right away.

The description is from Dr. Hartings' Notebook

Notes

The thickness of the film was measured using a Promas Sylvae System. The measures were taken on the negative portion of the film after the film was cut to size to fit the diffusion tube. Three measurements were taken resulting in 0.52mm, 0.55mm, and 0.58mm. The film thickness was calculated using the average of the measurements. The film thickness is 0.55mm. The film mass was also recorded weighing 0.2350g.

Table 1. Shows the times of when the UV vis measurements were taken from each side of the diffusion tube. The undiluted portions of each solution was returned back to the chamber. It is important to note that the 15 minute measurement was taken before the 5 minute aliquots could be returned; and the aliquots of the 15 minutes were not returned at all.


Table 1. Image:time stamps.png

After all UV Vis measurements were completed. The diffusion tube was disassembled and the film weight was recorded. After the experiment the film weight was 0.2125g the loss of mass is assumed to be because of the evaporation of water on the exposed outer edges of the film.

Image:UV-Vis.MG.and.water.chambers.png Image:UV-Vis.MG.chamber.png Image:UV-Vis.water.chamber.png Image:Concentration.vs.time.png


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