User:Alicia Rasines Mazo/Notebook/CHEM-581 Experimental Chemistry I/2014/09/05

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Tasks for 5 September 2014

  • Continuation from Dr. Hartings procedure
  • Calibration curves for malachite green absorbance were made using UV-Vis spectrometry. The ultimate purpose is to determine the equilibrium of the malachite green dye against bound MG.
  • New film synthesis was undertaken and film synthesis from Sept. 3 2014 was completed.

New Film synthesis

  • 1.0050 g of 22,000MW PVA was used to make the polymer film
  • 1.0004 g of PVA and 0.1077 g of sodium montmorillonite were used to make the 10% w/w polymer-clay film

UV-Vis analysis of MG leftover solutions

  • Dilutions of some of the MG solutions were made in order to be able to use the spectrometer
    • Diluted 200 ppm 100 times by adding 100μL to a 10 mL volumetric flask. This was done for both the polymer and polymer-clay in 200 ppm MG.
  • Also diluted 80 ppm 50 times by adding 200μL to a 10 mL volumetric flask. Done for both polymer and polymer-clay solutions.
  • Ran standards of MG solutions (0.2, 0.5, 1.1, 1.4, 1.7 and 2.0 ppm) in order to make calibration curves.

MG spectrum 050914.png <br.> From this, it can be seen that there are two major peaks at 425 nm and 615 nm. MG calibration 050914.png <br.> These calibrations curves show that the molar absorptivity at 425 nm is 0.0266 M-1cm-1 and 0.1293 M-1 cm-1 at 615 nm.

  • Ran UV-Vis on solutions left over after removing films from solution, to figure out the amount of dye not absorbed by films.

Absorbance of MG without PVA fil 050914.png Absorbance of MG post removal of polymer film.png <br.> Using Beer-Lambert's Law, the concentrations of leftover dye in solution were calculated:

  • At 425 nm,
    • PVA 2 ppm = 0.112 ppm
    • PVA 8 ppm = 0.639 ppm
    • PVA in diluted 80 ppm = 0.752. After accounting for dilution = 37.6 ppm
    • PVA in diluted 200 ppm = 0.714. After accounting for dilution = 71.4 ppm
    • PVA-clay 2 ppm = 0.112 ppm
    • PVA-clay 8 ppm = 0.226 ppm
    • PVA-Clay in diluted 80 ppm = 0.112. After accounting for dilution = 5.6 ppm
    • PVA-Clay in diluted 200 ppm = 0.188. After accounting for dilution = 18.8 ppm
  • At 615 nm,
    • PVA 2 ppm = 0.0696 ppm
    • PVA 8 ppm = 0.495 ppm
    • PVA in diluted 80 ppm =0.727. After accounting for dilution = 36.3 ppm
    • PVA in diluted 200 ppm = 0.712. After accounting for dilution = 71.2 ppm
    • PVA-clay 2 ppm = 0.031 ppm
    • PVA-clay 8 ppm = 0.093 ppm
    • PVA-Clay in diluted 80 ppm = 0.077. After accounting for dilution = 3.9 ppm
    • PVA-Clay in diluted 200 ppm = 0.147. After accounting for dilution = 14.7 ppm

Determining the amount of MG dye absorbed per mg of film

Note, the results were calculated using 615 nm values

  • PVA film in 2 ppm MG
    • 2 ppm - 0.0696 = 1.9304 ppm of MG absorbed
    • (1.9304 mg MG)/(L solution) × 0.010 L solution = 0.0193 mg MG/film
    • Since the clay film weighed 0.1286 g, the amount of MG dye absorbed in the polymer film into 2 ppm MG green solution is (0.0193 mg MG)/(0.1286)=0.00015 mg MG/mg polymer film.
  • PVA film in 8 ppm MG
    • 0.0013 mg MG/mg PVA film
  • PVA film in 80 ppm MG
    • 0.0049 mg MG/mg PVA film
  • PVA film in 200 ppm MG
    • 0.0121 mg MG/mg PVA film

<br.>

  • PVA-Clay film in 2 ppm MG
    • 0.00029 mg MG/mg PVA-Clay film
    • PVA-Clay film in 8 ppm MG
    • 0.0012 mg MG/mg PVA-Clay film
  • PVA-Clay film in 80 ppm MG
    • 0.0099 mg MG/mg PVA-Clay film
  • PVA-Clay film in 200 ppm MG
    • 0.0177 mg MG/mg PVA-Clay film

FTIR Analysis of Films with MG dye

FTIR 2 050914.jpeg

FTIR 1 050914.png