The presented ion chromatographic method is used for the simultaneous determination of HF, HNO 3 , H2SO4, short-chain organic acids and H2SiF6 in acidic texturing baths that are used in the wet chemical etching process of solar cell production. Fluoride, nitrate, sulphate and acetate are determined by conductivity detection after chemical suppression, while the silicon present in the form of hexafluorosilicate is detected spectrophotometrically as molybdosilicic acid after derivatization in the same analysis. The analytical results are validated by titration.
Energy production from renewable sources such as biomass, biogas, biofuels, water, wind and solar power is becoming increasingly important in our energy-hungry society. Particular interest is given to solar energy, which by human criteria is inexhaustible. Solar cells used in photovoltaic units convert the radiation energy in sunlight directly into electric energy.
This article describes an ion chromatographic method that separates all relevant components in the bath on an anion-exchange column and identifies them by dual detection in a single run. After suppressed conductivity detection of the acid anions, the undissociated silicic acid reacts in a post-column reaction (PCR) to form molybdosilicic acid, which is determined spectrophotometrically at 410 nm. The concentrations of fluoride and hexafluorosilicate are determined by way of a simple stoichiometric calculation that is performed by the chromatography software.
Instruments and Reagents
a) Instrument setup
b) Reagents and eluent