User:Melissa Novy/Notebook/CHEM-572/2013/02/05

Objectives

• Analyze LMT-95Ag with X-ray diffraction.
• Analyze LMT-95Ag filtrate with silver ion-selective electrode.
  • Make AgNO₃ calibration solutions.
• Begin ion exchange reaction with AgNO₃ and LMT to obtain LMT-100Ag.

X-Ray Diffraction on LMT Samples

• Protocol
  1. Press a small amount of sample into a low-background X-ray disc. Ensure that the sample is completely flat.
  2. Verify that no X-rays are escaping the X-ray diffractor.
  3. Place the sample into the X-ray holder.
  4. Run the X-ray at 0.5°/min from 2° to 50°.

• The following samples were analyzed: LMT-95Ag and Laponite.
• XRD data will be posted on 2013/02/06.

Calculations for Ag-LMT

  MW AgNO3: 169.87 g/mol
  MW Ag+: 107.86 g/mol
  CEC Laponite: 55 meqv/100 g
  1.5 g LMT × (55 meqv/100 g LMT) × (1 mol Ag+/1000 meqv) × (107.86 g Ag+/1 mol Ag+) × (1 mol Ag+/1 mol AgNO3) × (1 mol AgNO3/169.87 g AgNO3) × 100% = 0.000524 g AgNO3

AgNO₃ Calibration Solutions

• Calculations

  50 mL 0.01 M AgNO3
  0.050 L × 0.01 M AgNO3 × (169.87 g AgNO3/1 mol AgNO3) = 0.084935 g AgNO3

  50 mL 0.001 M AgNO3 by serial dilution
  (0.01 M AgNO3)(V1) = (0.001 M AgNO3)(50 mL)
  V1 = 5 mL 0.01 M AgNO3

  50 mL 0.0001 M AgNO3 by serial dilution
  (0.001 M AgNO3)(V1) = (0.0001 M AgNO3)(50 mL)
  V1 = 5 mL 0.001 M AgNO3

• 50 mL 0.01 M AgNO₃
  • Actual mass AgNO₃: 0.08910 g
  • Actual molarity: 0.0105 M AgNO₃
  • Actual ppm Ag⁺: 1132 ppm Ag⁺

  0.08910 g AgNO3 × (1 mol AgNO3/169.87 g AgNO3) = 0.000525 mol AgNO3
  0.000525 mol AgNO3/0.050 L = 0.0105 M AgNO3
  0.000525 mol Ag+ × (107.87 g Ag+/1 mol Ag+) = 0.05658 g Ag+
  (0.05658 g Ag+/50 g H2O) × 106 = 1132 ppm Ag+

• 50 mL 0.001 M AgNO₃
  • Volume of 0.0105 M AgNO₃ used: 4.762 mL
  • Actual ppm Ag⁺: 107.9 ppm Ag⁺

  (0.0105 M AgNO3)(V1) = (0.001 M AgNO3)(50 mL)
  V1 = 4.762 mL 0.0105 M AgNO3
  0.050 L × 0.001 M Ag+ × (107.87 g Ag+/1 mol Ag+) = 0.005393 g Ag+
  0.005383 g Ag+/50 g H2O × 106 = 107.9 ppm Ag+

• 50 mL 0.0001 M AgNO₃
  • Volume of 0.001 M AgNO₃ used: 5 mL
  • Actual ppm Ag⁺: 10.78 ppm Ag⁺

Laponite-Ag⁺ Ion Exchange

• The protocol from 2013/01/29 was followed. However, the solution will be stirred for 1 week, instead of 24 hours.
• Theoretical mass Laponite: 1.5 g
  • Actual mass Laponite: 1.49711 g

• Theoretical mass AgNO₃: 0.000524 g
  • Actual mass AgNO₃: 0.00622 g

• Observations: The solution became opaque and white in color after all components were added.