Van Deun, Rik

Van Hecke, Kristof

Verdonck, Tim

Verpoort, Philippe

English

Ghent University Academic Bibliography

c(LiCl)With support fromSpectroscopic Study of Cr(III) in  Water and Deep-Eutectic Solvents Using MCR-ALS 	T. Verdonck1,2,3, P. Verpoort2, R. Van Deun3, K. Van Hecke1 Tim.Verdonck@UGent.be 1XStruct, Ghent University, Krijgslaan 281-S3, B-9000 Gent, Belgium 2OCAS nv, Pres. J.F. Kennedylaan 3, B-9060 Zelzate 3L3, Luminescence Lanthanide Lab, Ghent University, Krijgslaan 281-S3, B-9000, Belgium Methods1. Abbott, A. P., Frisch, G. & Ryder, K. S. Electroplating Using Ionic Liquids. Annu. Rev. Mater. Res. 43, 335–358 (2013). 2. Jaumot, J., de Juan, A. & Tauler, R. MCR-ALS GUI 2.0: New features and applications. Chemom. Intell. Lab. Syst. 140, 1–12 (2015). 3. Elving, P. J. & Zemel, B. Absorption in the Ultraviolet and Visible Regions of Chloroaquochromium(III) Ions in Acid Media. J. Am. Chem. Soc. 79, 1281–1285 (1957).ReferencesSemi-industrial Pilot LineMol%	Ethylene	GlycolMol%	ChClMol%	EGSteel ProductionHard ChromeDuring the cold rolling of steel, the thickness of the steel strips is reduced by applying a high pressure with two rolling cylinders.These cylinders have to be protected from the harsh conditions. Hence, they are coated with a hard chromium layer.Chromium(VI)This layer is typically electro-deposited from an aqueous solution containing the toxic and carcinogenic Cr(VI). Chromium(III)Powered by the quest to a more sustainable production process, OCAS NV has already been working for six years on a patented Cr(VI)-free alternative, using a Cr(III)-based deep-eutectic solvent (DES) as electrolyte1. However, there still exists a lack of fundamental knowledge on the deposition mechanism.Research GoalThis project focuses on the elucidation of the coordination chemistry of the Cr(III) species in the DES as a function of composition and the presence of additives to predict the in-use properties of the eventual hard chromium layer.IntroductionSamplesSeveral series of samples containing Cr(III) were prepared (aqueous or DES), with a continuous variation of one constituent (e.g. concentration of LiCl, Ethylene Glycol, etc.)Coordination CompoundsEach sample contains an unknown mixture of the possible chromium(III) coordination compounds. It is expected that there exists a continuous variation of the species along each series of samples.SpectroscopyThis variation in coordination chemistry can be studied by means of several spectroscopic techniques such as UV/Vis spectroscopy, Extended X-ray Absorption Fine Structure (EXAFS), Raman spectroscopy, etc.MCR-ALSMulti-variate Curve Resolution - Alternating Least Squares (MCR-ALS)2 is a chemometrical technique based on similar principles as Principal Component Analysis (PCA), but specifically designed for the deconvolution of series of spectra to the pure spectra of the constituents and the corresponding concentration profiles.Sample SeriesCrCl3.6H2O dissolved in water results in hexaaquachromium(III) after equilibration (blue) ?Possible additives: - LiCl - Ethylene Glycol + Choline Chloride - Perchloric Acid - Etc.These addit ives generally result in a green-shiftPure UV/Vis SpectraHigher chlorinated chromium(III) speciesGreen-shift in UV/Vis spectra*Pure spectra obtained through Ion Exchange Chromatography (IEC) experiments of Cr(III) in waterDue to the promising features of this new electrodeposition solvent, a flexible semi-industrial pilot plant has been designed in OCAS NV. In this way, several set-ups, IL compositions, additives, etc. can be tested and evaluated on a large scale, and compared with lab scale experiments.MCR-ALS

Spectroscopic study of Cr(III) in water and deep-eutectic solvents fusing MCR-ALS

https://biblio.ugent.be/publication/8511685/file/8511686.pdf

Spectroscopic study of Cr(III) in water and deep-eutectic solvents fusing MCR-ALS

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