Spectrophotometric determination of zirconium and hafnium with 4-(2-pyridylazo)resorcinol

Abstract

Reaction behavior of zirconium and hafnium with 4-(2pyrldylazo)resorcinol Is established under various conditions. Optimum conditions for a very sensitive spectrophotometric procedure are outlined for the determination of zirconium and hafnium. Zirconium and hafnium react quantitatively with the reagent In alkaline pH from 8 to 9.2 and 8 to 9.8, respectively, to form 1:2 water-soluble complexes. The molar absorptivity for zirconium and hafnium Is 66 000 and 77 400, respectively. The order of addition of the reagent, metal Ion, and buffer solution Is evaluated. It Is concluded that both zirconium and hafnium solutions must be maintained at higher acidities to react quantitatively with the reagent. A number of foreign Ions are tested for their Interference and the use of masking agents and selective extractive agents Is outlined. The relative standard deviations are ±0.5 % and ±0.7 for the determination of 30 pq of zirconium and 40 pg of hafnium, respectively.

Novel approach for the determination of zirconium by solid-phase spectrophotometry

“…UV-Vis spectrophotometric methods have been widely used due to simplicity, rapidity, low costs and wide applications [23][24][25][26]. For this purpose, widely-used chromogenic reagents are pyrocatechol violet [27], alizarin red S [28][29][30], arsenazo I and III [27][28][29][30][31], xylenol orange [21,[34][35][36][37], Janus Green dye [38], 2,4-dinitrophenol-(6-azo-2)-1-napthol-3,8-disulphonic acid (picramine <epsilon>) [39], 2-(6-bromo-2-benothiaoylazo) 5-diethylaminophenol and sodium lauryl sulphate [40], 4-(2-pyridiylazo) resorcinol (PAR) [41,42], 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol [43], 5,7-dibromo-8-hydroxylquinoline [44], chorme azurol S [45], for determination of Zr(IV) by spectrophotometry was reported. Some methods have low sensitivity and selectivity and others have high sensitivity but low selectivity.…”

Development of a simple and rapid EDXRF method for quantification of ZrO2 and HfO2 in aqueous and organic process stream solutions generated from a zirconium extraction facility

“…Various techniques are available in the literature for the determination of zirconium covering a wide range of concentrations. They include gravimetry, 3 wavelength dispersive X-ray fluorescence (WDXRF) spectrometry, 4,5 total reflection X-ray fluorescence (TXRF), 6 spectrophotometry, 7,8 ICP-AES, 9 AAS 10 etc. Among the available techniques, gravimetry and spectrophotometry methods are cumbersome and time-consuming methods and, therefore, are not preferred choices for reporting the results of process stream solutions where they are to be reported rapidly for taking decisions on downstream processing and also monitoring the zirconium extraction process on a real-time basis.…”