FERRATE (VI) ANALYSIS BY SPECTROPHOTOMETRY AND VOLTAMMETRY [report]

A. S. Venkatadri, W. F. Wagner, H. H. Bauer
1970 unpublished
Spectrophotometrlc and voltaanetric methods were developed for the analysis of potassium ferrate(VI) in dilute solutions, where the standard chromite method is inapplicable. A direct proportionality prevails between the ferrate concentration and the absorbance on the one hand, And the ferrate concentration and the ferrate reduction current on the other. However, voltaasetry has greater precision than spectrophotometry in \ery dilute solutions. INTKoUUCTION Various aspects of ferrate(VI)
more » ... y such as its production (chemical e fa 7 8 and electrochemical ), stability * , oxidation properties and magnetic pro-9 perties have been explored for the past several decades. Any such study necessitates the development of a reliable analytical technique capable of reasonable accuracy at low concentrations of ferrate. The very low solubility of potassium ferrate in strongly basic solutions, and its instability, lead to difficulties in the standardization of analytical methods. Analytical Methods for Ferrate: Three types of methods for ferrate analysis will be discussed: (a) Chemical, (b) Spectrophotoaetri:, and (c) Electrorhemical. The most reliable of the chemical nn-thods is the chromite method developed by Schreyer and coworkers . This method, based on oxidation of chromiumUII) to chromate(VI) by ferrate in strongly alkaline solutions, was found to give low values in very dilute solutions, probably due to incomplete oxidation of chromite. However, consistent results arc obtainable for ferrate analysis in solid samples under controlled tltration conditions, and this information la necessary for the standardization of the spectrophotometric and the electrochemical methods. Spectrophotometry and voltamnetry appeared more promising Chan the chromite method for ferrate analysis in dilute solutions. EXPLKIMEMAL EQUIPMENT AND APPARATUS The last ruiru-nt.it 1 on employed for spfctrophotometry was a Uausch and Lomb Spectronlc 20; for vol tammetry, a Prlnrrton Applii-d Kosoarrh Model 170 Klfctru-lifmisi ry System was used. UNCLASSIFIED " Iccurlty CUaalflcation KIV momot NOLI WT KOLI mi MOL c NT ferrate analysis r' UNCLASSIFIED Security Oasairicalion
doi:10.21236/ad0710331 fatcat:ztotozfs3fapdpmjrcj7xx734q