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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
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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 SamplePortage, IN plant Wash Pit Waste SampleBeaver Dam, KY plant
ICP-OES • Inductively Coupled Plasma - Optical Emission Spectrometry • Sample is nebulizedto 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
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
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)
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)
Bibliography • http://neoindustriesllc.com/index.php