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
- Plug the Na+ electrode into the SympHony meter and turn on instrument
- Then press the arrows until ISE (ion selective electrode) and mV (millivolts) appear on the screen
- Remove the electrode from the storage solution
- Rinse the electrode with distilled H2O and thoroughly dry it with a KimWipe
- Place the electrode directly into the 1ppm CuSO4 solution for analysis
- Let the solution and electrode equilibrate for a set period of time (between 2-5 minutes) and then press measure
- Once the measurement is finalized, record the value observed
- 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 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
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
ISE and pH measurements
| Solution Tested
|
pH of solution with adjustment
|
ISE values with adjustment[mV]
|
| 1ppm CuSO4 |
9.52 |
-215.5
|
| 2ppm CuSO4 |
9.48 |
-207.5
|
| 5ppm CuSO4 |
9.47 |
-207.9
|
| 10ppm CuSO4 |
9.43 |
-211.7
|
| 15ppm CuSO4 |
9.45 |
-151.1
|
| 7.4ppm Cu2+ 100%CEC 1min filtrate |
9.53 |
-201.2
|
| 10ppm Cu2+ 100%CEC 1min filtrate |
8.47 |
-174.1
|
| 7.4ppm Cu2+ 100%CEC 5min filtrate |
9.52 |
-200.5
|
| 10ppm Cu2+ 100%CEC 5min filtrate |
8.45 |
-172.5
|
| 10ppm Cu2+ 100%CEC 10min filtrate |
8.51 |
-172.3
|
| 7.4ppm Cu2+ 100%CEC 10min filtrate |
9.53 |
-199.0
|
| 7.4ppm Cu2+ unmodified Na-MT 1min |
8.37 |
-128.2
|
| 10ppm Cu2+ unmodified Na-MT 1min |
8.45 |
-142.1
|
| 7.4ppm Cu2+ unmodified Na-MT 5min |
8.47 |
-112.7
|
| 10ppm Cu2+ unmodified Na-MT 5min |
8.50 |
-99.2
|
| 7.4ppm Cu2+ unmodified Na-MT 10min |
8.44 |
-138.0
|
| 10ppm Cu2+ unmodified Na-MT 10min |
8.44 |
-134.5
|
DSC Sample Preparation
RECALL DSC PROCEDURES FROM 9/17/12
| Film Type
|
Sample Mass (mg)
|
Pan / Lid Mass (mg)
|
| Uncrosslinked Plain PVOH 130K |
2.83 |
49.49
|
| Uncrosslinked PVOH 22K, HCl |
2.84 |
49.50
|
| Uncrosslinked PVOH 130K, HCl |
2.60 |
50.63
|
| Uncrosslinked PVOH 130K, 10% succinic acid, HCl |
2.99 |
50.36
|
| Uncrosslinked PVOH 22K, H2SO4 |
3.05 |
48.94
|
| Uncrosslinked PVOH 22K, H3PO4 |
3.01 |
48.43
|
| Uncrosslinked PVOH 130K, H3PO4 |
2.96 |
49.73
|
| Uncrosslinked PVOH 130K, 15% maleic acid, H3PO4 |
2.82 |
49.39
|
| Uncrosslinked PVOH 130K, 15% succinic acid, H3PO4 |
2.82 |
50.05
|
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
|
PVOH Research
