Uranyl ions Subject

An interesting method, though limited in scope, for improving the sensitivity of conventional polarography makes use of catalytic eflFect of a desired ion on some component of the solution. Thus the catalytic eflFect of uranyl ions on nitrate reduction was used by Korkisch and coworkers (30) however, this method is subject to many interferences. 

In the absence of chemical quenching, uranyl compounds have long luminescent lifetimes and high luminescent quantum efficiency [21]. Often, however, the excited state reacts chemically. The photochemistry of the ion, the most famous example of which is the uranyl oxalate actinometer, has generated an enormous body of work and been the subject of comprehensive reviews [22,23]. It can occur both in solution and in the solid state. The most common reaction is the oxidation of organic substrates. Both the photochemistry and the remarkable properties of the covalent bond, demand a satisfactory interpretation in terms of the electronic structure. 

For our publication in this subject [14], we focused on elucidating the structure of cellulose acetate (CA)-U02[VI), because despite the importance of using cellulose derivatives as chelating resins for removing rare metal ions in waste- and sea-water, before year of publishing of this study, there was a lack of Information regarding the structure of cellulose acetate-U02 (VI) complexes. We had prepared cellulose acetate-U02[VI] complex samples from three degrees of substitution of viscose pulp with uranyl acetate. The role of acetyl content of CA on the amount of chelated uranium was also evaluated [Table 7.6]. 

The determination of U ions (as uranyl) using a macrocylic N-subsstituted amide (26) as the ionophore was reported by Shamsipiu et al. in 2002. The ISE in question was based on (26). It displayed a Nemstian response (29.2 mV per decade) with a DL of 3.5 x 10 M and was found to operate over a wide concentration range (from 5.0 x 10 to 1.5 X 10 M). Gratifyingly, this system displayed good selectivity for luanyl ions and was subject to almost negligible interference from other cations (e.g., alkali, alkaline earth, transition, and heavy metal ions). ... 

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