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Redox and adsorption processes of hydrolyzed uranyl species on a mercury electrode from sodium chloride solutios
Author(s) -
Djogić Renata,
Krznarić Damir,
Branica Marko
Publication year - 1997
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140091214
Subject(s) - uranyl , chemistry , inorganic chemistry , cyclic voltammetry , chronoamperometry , adsorption , hanging mercury drop electrode , electrochemistry , dropping mercury electrode , chloride , redox , voltammetry , electrode , ion , organic chemistry
Reduction and adsorption processes of hydrolyzed uranyl species on the mercury drop electrode, from 0.55 mol L −1 NaCl, were studied by electrochemical cathodic stripping techniques: cyclic voltammetry, alternating current voltammetry, chronoamperometry and double potential step chronocoulometry. The only uranyl species adsorbed on the Hg electrode (between pH 5 and 7) was found to be uncharged uranyl dihydroxide, as well as its reduction product. At bulk concentrations between 3 and 5 μmol L −1 that reactant forms an adsorbed compact film as a result of surface polymerization, nucleation or other condensation processes. The adsorption isotherm at pH 6.2 and −0.2 V was measured. It was fitted with a Frumkin type isotherm. At the plateau. a reduction current corresponding to 6.7 × 10 −9 mol cm −2 of uranyl ions was measured. This represents on the average 7 adsorbed layers of UO 2 (OH) 2 0 , presuming an orthorhombic crystal cell structure. Multilayer adsorption is certain even if a polymeric form of uranyl dihydroxide was considered.