Chromium Team
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Transcript of Chromium Team
CHROMIUM TEAM
Ken AndrzejewskiYe Eun Oh
Jasmine Podell
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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
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Chrome Plating Bath Samples from
Portage, IN, North and South baths
Chrome Plating Bath Sample from Beaver
Dam, KY
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Wash Pit Waste SamplePortage, IN plant
Wash Pit Waste SampleBeaver Dam, KY plant
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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
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ICP-OES
[Cr] ppm max min Int
50 101295 120 101175
20 41010 101.5 40908.5
10 22600 95.5 22504.5
5 10611.5 92 10519.5
2.5 5311 89.5 5221.5
1 2347 91.5 2255.5
0 179 78.5 100.5
Example: Calibration Test 1
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0 10 20 30 40 50 600
20000
40000
60000
80000
100000
120000
f(x) = 2017.50698099825 x + 590.804597379327R² = 0.999529064524506
Calibration Curve 1
Concentration (ppm)
Intensity
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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 acidCheck if they are acidicAdd 100µL of DI waterWait for 10 minutesRecord
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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
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DPC Cont. Problem
If the concentration is too high, the color will disappear very quickly
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DPC Cont.
Concentration (ppm) λ A λ max A
1 540 0.375 541 0.377
2.5 540 0.865 542 0.866
5 540 0.994 542 0.996
10 540 0.624 540 0.624
15 540 0.869 540 0.869
20 540 0.696 542 0.698
UV-Vis result (DPC on standards 1:3 dilution)
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Starch Indicator This process uses 0.5M Sulfuric acid, Potassium
iodide, starch indicator, DI water, and our chromium solutions.
Take 25mL volumetric flaskTake 20mL of the Chromium standard or
sample 3 drops of sulfuric acidA small spatula of Potassium iodide3 drops of starch indicatorDI water
Swirl the solution
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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
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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
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Starch Indicator Cont.
Concentration (ppm) λ A λ max A
1 540 0.198 550 0.210
2.5 540 0.539 500 0.558
5 540 0.553 572 0.594
10 540 1.564 557 1.623
15 540 Out of Range
20 540 “
UV-Vis result (Starch indicator on standards)
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X-Ray Fluorescence Spectrometry of Wash Pit Solids
Element %
Cr 19.29 +/- 1.04
Fe 58.92 +/- 1.56
Pb 16.17 +/- 0.524
Zr 1.45 +/- 0.10
Mo 4.17 +/- 0.18
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Pictures
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Pictures
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Bibliography http://neoindustriesllc.com/index.php