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Proceedings Paper

Absorption spectroscopy of trivalent chromium in distilled water and in buffers at different pH values in the visible spectral range
Author(s): Anna Grazia Mignani; Andrea Romolini
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Paper Abstract

Chromium is frequently used in industrial processes. However, its residue is rarely discharged directly into the sewers, because of the high pollution level. There are several companies that deal with sewage collection and recycling processes. Since absorption spectroscopy during the recycling process is supposed, high concentration solutions in the 2.6 - 520 mg/l range have been considered. Trivalent chromium (Cr(III) solutions in distilled water and in buffers at pH values 2, 3, 4 and 6 were analyzed by means of a dual beam spectrophotometer in the 250 - 850 nm spectral range, using a 100 mm path length. The spectra showed two absorption peaks, around 400 nm and 580 nm, respectively. The measurements indicated that only Cr(III) concentrations higher than 26 mg/l can be detected, and that the spectral position of the absorption peaks and the absorbance relative to each peak are different for solutions in distilled water or in buffers, and are pH-dependent. The behavior of absorbance as a function of pH for all the concentrations considered was investigated for the two peaks. The value of absorbance increased with the pH. All the measurements carried out demonstrated the possibility of performing on-line absorption spectroscopy of water samples using current optical fiber technology.

Paper Details

Date Published: 31 August 2000
PDF: 8 pages
Proc. SPIE 4074, Applications of Optical Fiber Sensors, (31 August 2000); doi: 10.1117/12.397908
Show Author Affiliations
Anna Grazia Mignani, Istituto di Ricerca sulle Onde Elettromagnetiche (Italy)
Andrea Romolini, Istituto di Ricerca sulle Onde Elettromagnetiche (Italy)


Published in SPIE Proceedings Vol. 4074:
Applications of Optical Fiber Sensors
Alan J. Rogers, Editor(s)

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