Chromium Team Ken Andrzejewski Ye Eun Oh Jasmine Podell 4/24/2017 Ken Andrzejewski Ye Eun Oh Jasmine Podell Chromium Team
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
Chrome Plating Bath Samples from Portage, IN, North and South baths Chrome Plating Bath Sample from Beaver Dam, KY
Wash Pit Waste Sample Portage, IN plant Wash Pit Waste Sample Beaver Dam, KY plant
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
ICP-OES Example: Calibration Test 1 [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 2255.5 179 78.5 100.5
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
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
DPC Cont. Problem If the concentration is too high, the color will disappear very quickly
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
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
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
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
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 “
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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Bibliography http://neoindustriesllc.com/index.php