User:Alicia Rasines Mazo/Notebook/CHEM-581 Experimental Chemistry I/2014/09/19

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Tasks for 19 September

  • To begin new synthesis of PVA and 10% w/w PVA-Clay films
  • To finish analysing PVA-Malachite green data
  • To start analysis on X-ray
  • To complete preparation of ionic liquid modified clay
  • To set up experiments for the measurement of absorbance of Mercury and Arsenic by films

New film synthesis

  • 1.0022 g 22,000 MW PVA were used to make the PVA polymer film
  • 1.0044 g 22,000 MW PVA and 0.1104 g Na Montmorillonite were used for the synthesis of 10% w/w PVA-Clay polymer film.

Completing preparation of ionic liquid modified clay

Continued from Set. 17 2014

  1. Ground with mortar
  2. Stored in dissecator

Measuring the Absorbance of Mercury and Arsenic

Film Solution Empty glass vial (g) Glass Vial + film (g) Film weight (g)
PVA 150 ppm As 13.0969 13.2069
100 ppm As 13.1262 13.2127
50 ppm As 13.1340 13.2340
150 ppm Hg 13.0145 13.1050
100 ppm Hg 13.0742 13.1521
50 ppm Hg 13.1254 13.2356
10% PVA-Clay 150 ppm As 13.1197 13.2435
100 ppm As 13.0765 13.1374
50 ppm As 13.1298 13.2529
150 ppm Hg 13.1706 13.2172
100 ppm Hg 13.1208 13.1908
50 ppm Hg 13.1493 13.2317
  • Note: in order to make up the specified dilutions (Table above) of As and Hg, dilutions of stock solutions were prepared.
  • Eleni prepared the arsenic dilutions
  • James and Madeleine prepared the mercury dilutions
  • Dilutions:
    • 0.0499 mol As/L × 74.921 g As/mol × 1000 mg/g = 3738.56 mg/L = 3738.56 ppm
    1. (3738.56 ppm)(V)=(150ppm)(50mL)
      • 2mL in 50mL volumetric
    2. (3738.56 ppm)(V)=(100ppm)(50mL)
      • 1.34mL in 50mL volumetric
    3. (3738.56 ppm)(V)=(50ppm)(50mL)
      • 0.668mL in 50mL volumetric
    • 268 ppm Hg (13.4 mM HgCl2)
    1. (268 ppm)(V)=(150 ppm)(50mL)
      • 27.98mL in 50mL volumetric
    2. (268 ppm)(V)=(100 ppm)(50mL)
      • 18.66mL in 50mL volumetric
    3. (268 ppm)(V)=(50 ppm)(50mL)
      • 9.33mL in 50mL volumetric

10 mL of each solution were poured into glass vials containing the PVA-polymer films

Second Analysis of UV-Vis MG data for PVA-polymer film

MGPVAUVVis 190914.png <br.> Used MG calibration curves obtained on Sept. 5 2014

  • ε615nm=0.1293 M-1cm-1
  • A=εbc.

Solving for concentration:

  • PVA in 2ppm = 0.031/(0.1291 M-1)= 0.240 ppm MG remain in solution (rest absorbed by film)
PVA in MG left in solution (ppm) MG absorbed by film (ppm)
2 ppm MG 0.240 1.760
8 ppm MG 0.913 7.087
80 ppm MG 31.70 48.30
200 ppm MG 92.00 108.0

Note that 10 of MG solution were added per vial, so that 2 ppm MG = (1.760 mg MG/L)×0.010L=0.0176 mg MG/film <-- absorbed amount <br.> The weight of the film submerged in 2 ppm MG solution was 0.1060 g. Refer to Sept. 12 2014 for further film weights.

  • (0.0176mg MG/0.01060g film)=0.0166 mg MG/g film
  • 8 ppm: 0.728 mg MG/g film
  • 80 ppm: 4.49 mg MG/g film
  • 200 ppm: 10.8 mg MG/g film

Measuring amount of MG absorbed onto glass vial

UVVIS Controls 190914.jpeg<br.> As in previous section, the molar absorptivity and calibration curve from Sept. 5 2014 were used. <br.> 80 ppm MG in glass vial control: 42.87 ppm were absorbed by glass (Calculations as show in previous section)

  • 0.429 mg MG/glass vial

200 ppm MG in glass vial control: 88.63 ppm were absorbed by glass

  • 0.886 mg MG/glass vial