User:Karlena L. Brown/Notebook/PVOH Research/2012/10/09

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OBJECTIVES

  • Remake CuSO4 standard solutions for atomic absorption
  • Use the ion selective electrode to measure all CuSO4 solutions established
  • Prepare PVOH samples for DSC testing and analysis
  • Collect all data and experimental results from DSC testing and analysis

Ion Selective Electrode Procedures

  1. Plug the Na+ electrode into the SympHony meter and turn on instrument
  2. Then press the arrows until ISE (ion selective electrode) and mV (millivolts) appear on the screen
  3. Remove the electrode from the storage solution
  4. Rinse the electrode with distilled H2O and thoroughly dry it with a KimWipe
  5. Place the electrode directly into the 1ppm CuSO4 solution for analysis
  6. Let the solution and electrode equilibrate for a set period of time (between 2-5 minutes) and then press measure
  7. Once the measurement is finalized, record the value observed
  8. Create a standard ISE calibration curve

REPEAT ABOVE PROCEDURES FOR ALL CuSO4 STANDARD SOLUTIONS:2 ppm, 5 ppm, 10 ppm, AND 15 ppm

REPEAT ABOVE PROCEDURES FOR ALL Na2SO4 STANDARD SOLUTIONS:1 ppm, 2 ppm, 5 ppm, 10 ppm, 15 ppm, AND 20 ppm

REPEAT PROCEDURES FOR INTERVAL AQUEOUS FILTRATE CuSO4 EXCHANGED CLAY SOLUTIONS: 7.4 ppm AND 10 ppm

Ion Selective Electrode Standard Dilutions & Calculations

Na2SO4 Dilution Standards

5mL 1 ppm Na2SO4 requires:
 (1000 ppm Na2SO4)V1 = (1 ppm Na2SO4)(5mL)
   V1 = 0.005mL
5mL 5 ppm Na2SO4 requires:
 (1000 ppm Na2SO4)V1 = (5 ppm Na2SO4)(5mL)
   V1 = 0.025mL
5mL 10 ppm Na2SO4 requires:
 (1000 ppm Na2SO4)V1 = (10 ppm Na2SO4)(5mL)
   V1 = 0.05mL
5mL 15 ppm Na2SO4 requires:
 (1000ppm Na2SO4)V1 = (15 ppm Na2SO4)(5mL)
   V1 = 0.075mL
5mL 20 ppm Na2SO4 requires:
 (1000 ppm Na2SO4)V1 = (20 ppm Na2SO4)(5mL)
   V1 = 0.100mL

CuSO4 Dilution Standards

12mL 1 ppm CuSO4 requires:
 (20ppm CuSO4)V1 = (1ppm CuSO4)(12mL)
   V1 = 0.6mL
12mL 2 ppm CuSO4 requires:
 (20ppm CuSO4)V1 = (2ppm CuSO4)(12mL)
   V1 = 1.2mL
12mL 5 ppm CuSO4 requires:
 (20ppm CuSO4)V1 = (5ppm CuSO4)(12mL)
   V1 = 3mL
12mL 10 ppm CuSO4 requires:
 (20ppm CuSO4)V1 = (10ppm CuSO4)(12mL)
   V1 = 6mL
12mL 15 ppm CuSO4 requires:
 (20ppm CuSO4)V1 = (15ppm CuSO4)(12mL)
   V1 = 9mL


Image:CuSO4_ISE_Standards.JPG

Ion Selective Electrode Sample Preparations & Results

Before collecting sample measurements from the ion selective electrode instrument:

  • Upon testing the pH of the standard solutions, it was concluded that the pH was too low (~7.8)
  • Therefore, pH adjustments made for each solution: 0.1mL of ionic strength adjuster (4M pH adjuster containing NaOH) + 3mL of sample solution
  • The ionic strength pH adjuster adjusted the pH of the solutions between 8 and 10
  • The solvent used to dilute each solution was distilled H2O


ISE and pH measurements

Solution Tested pH of solution with adjustment ISE values with adjustment[mV]
1ppm CuSO49.52-215.5
2ppm CuSO49.48-207.5
5ppm CuSO49.47-207.9
10ppm CuSO49.43-211.7
15ppm CuSO49.45-151.1
7.4ppm Cu2+ 100%CEC 1min filtrate9.53-201.2
10ppm Cu2+ 100%CEC 1min filtrate8.47-174.1
7.4ppm Cu2+ 100%CEC 5min filtrate9.52-200.5
10ppm Cu2+ 100%CEC 5min filtrate8.45-172.5
10ppm Cu2+ 100%CEC 10min filtrate8.51-172.3
7.4ppm Cu2+ 100%CEC 10min filtrate9.53-199.0
7.4ppm Cu2+ unmodified Na-MT 1min8.37-128.2
10ppm Cu2+ unmodified Na-MT 1min8.45-142.1
7.4ppm Cu2+ unmodified Na-MT 5min8.47-112.7
10ppm Cu2+ unmodified Na-MT 5min8.50-99.2
7.4ppm Cu2+ unmodified Na-MT 10min8.44-138.0
10ppm Cu2+ unmodified Na-MT 10min8.44-134.5

DSC Sample Preparation

RECALL DSC PROCEDURES FROM 9/17/12

Film Type Sample Mass (mg) Pan / Lid Mass (mg)
Uncrosslinked Plain PVOH 130K2.8349.49
Uncrosslinked PVOH 22K, HCl2.8449.50
Uncrosslinked PVOH 130K, HCl2.6050.63
Uncrosslinked PVOH 130K, 10% succinic acid, HCl2.9950.36
Uncrosslinked PVOH 22K, H2SO43.0548.94
Uncrosslinked PVOH 22K, H3PO43.0148.43
Uncrosslinked PVOH 130K, H3PO42.9649.73
Uncrosslinked PVOH 130K, 15% maleic acid, H3PO42.8249.39
Uncrosslinked PVOH 130K, 15% succinic acid, H3PO42.8250.05

Notes

  • The 1 ppm Na+ solution provided an ISE value outside of the expected calibration curve due to the > 1 ppm LOD (limit of detection)
  • Recommendation: Make standards larger than 25 ppm Na+ to create more accurate calibration curve
  • The ISE values of the CuSO4 solutions are meaningless as they were obtained with a sodium electrode



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