1. Chromium Team Ken Andrzejewski Ye Eun Oh Jasmine Podell
4/24/2017
Ken Andrzejewski
Ye Eun Oh
Jasmine Podell
Chromium Team

3. Goals
True classification of 7 chrome plating baths at various NEO Industries plants – What are the similarities and differences, and does it make a difference
Find alternatives for wash and soak tank disposal to save money and reduce toxicity

4. Chrome Plating Bath Samples from Portage, IN, North and South baths
Chrome Plating Bath Sample from Beaver Dam, KY

5. Wash Pit Waste Sample Portage, IN plant
Wash Pit Waste Sample Beaver Dam, KY plant

6. ICP-OES Inductively Coupled Plasma - Optical Emission Spectrometry
Sample is nebulized to micro-droplet particles which are passed through a plasma stream
Particles are excited and emit light
Emission spectra are determined to identify specified element

7. ICP-OES Example: Calibration Test 1 [Cr] ppm max min Int 50 101295 120
101175 20
41010
101.5 10
22600
95.5 5 92
2.5
5311
89.5
5221.5 1
2347
91.5
2255.5
179
78.5
100.5

9. Diphenylcarbazide (DPC)
This includes use of 3M Sulfuric acid, DI water, and DPC dissolved in Ethanol.
Procedure
Take 3mL of each standard
Add 200µL of Sulfuric acid
Check if they are acidic
Add 100µL of DI water
Wait for 10 minutes
Record

10. Chromium Team
4/24/2017
DPC Cont.
The result
In presence of hexavalent Chromium, the solution turns magenta to red color
The higher the concentration, the darker the color
Make a 1:3 dilution of acidified standards with DI water and perform the DPC test
After the color appears, test them in UV-Vis

11. DPC Cont.
Problem
If the concentration is too high, the color will disappear very quickly

12. DPC Cont. UV-Vis result (DPC on standards 1:3 dilution)
Concentration (ppm) λ A
λ max 1
540
0.375
541
0.377
2.5
0.865
542
0.866 5
0.994
0.996 10
0.624 15
0.869 20
0.696
0.698

13. Starch Indicator
This process uses 0.5M Sulfuric acid, Potassium iodide, starch indicator, DI water, and our chromium solutions.
Take 25mL volumetric flask
Take 20mL of the Chromium standard or sample
3 drops of sulfuric acid
A small spatula of Potassium iodide
3 drops of starch indicator
DI water
Swirl the solution

14. Starch Indicator Cont. The color produced by this process is purple.
A lighter purple indicates less Chromium VI
A darker purple indicates more Chromium VI

15. Starch Indicator Cont. The solutions are put into the UV-Vis
Material absorbs at a certain wavelength
Recorded the absorption at 540 nm and the max wavelength and its absorbance
Concentration of the samples can be determined based on the absorbance and wavelengths of the standards

16. Starch Indicator Cont. UV-Vis result (Starch indicator on standards)
Concentration (ppm) λ A
λ max 1
540
0.198
550
0.210
2.5
0.539
500
0.558 5
0.553
572
0.594 10
1.564
557
1.623 15
Out of Range 20 “

17. X-Ray Fluorescence Spectrometry of Wash Pit Solids
Element % Cr
/- 1.04 Fe
/- 1.56 Pb / Zr
1.45 +/- 0.10 Mo
4.17 +/- 0.18

18. Pictures

19. Pictures

20. Bibliography