Using a bio-inspired copper complex to investigate reactive mass transfer around an oxygen bubble rising freely in a thin-gap cell

• Published in: Chemical engineering science 2019-11, Vol.207, p.1256-1269
• Main Authors: Felis, Francisco, Strassl, Florian, Laurini, Larissa, Dietrich, Nicolas, Billet, Anne-Marie, Roig, Véronique, Herres-Pawlis, Sonja, Loubière, Karine
• Format: Article
• Language: English
• Subjects: Bioinspired copper complex; Chemical and Process Engineering; Chemical engineering; Chemical Sciences; Engineering Sciences; Experimental imaging; Mass transfer; Reactive bubbly flows; Thin-gap cell
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2019.07.045

[Display omitted] •Bio-inspired copper complexes are tailored to explore reactive gas-liquid mass transfer.•Single pure oxygen bubbles are generated in a thin-gap cell which gap is 1 mm.•Gap- and time-averaged oxygen concentration fields are measured in the far-field wake.•A representation Sherwood-Peclet enables to gather the results.•Intrinsic Sherwood numbers can be determined from the calculated enhancement factor. The present study describes an original colorimetric method to visualize and quantify the local oxygen mass transfer around a rising bubble in reactive media. This method is based on the use of a colorless bio-inspired copper complex, Cu(btmgp)I, specially tailored for the study, which, dissolved in acetonitrile, oxidizes into an orange copper-complex [Cu2O2(btmgp)2]I2. The latter complex, unstable at ambient temperature, decays quite fast into two Cu(II) complexes, leaving a permanent pale-green color as final products. The flow investigated consists in a pure oxygen single bubble rising freely in a confined thin-gap cell (400 × 200 × 1 mm). A wide range of motion regimes for the bubbles are observed as the Archimedes number ranges from 860