Sorption behaviour of uranium on birnessite, a layered manganese oxide

Thorium Uptake on Synthetic Inorganic Ion Exchangers

“…The affinity of K-antimonysilicate resulted in K d exceeded 10 4 mL g À1 in the most dilute solution, 0.05 M KNO 3 , decreased to 2.2 Â 10 3 mL g À1 in 1 M KNO 3 ; the latter was ten-folds more than that recorded for Na-antimonysilicate in 1 M NaNO 3 , that is, 2.2 Â 10 2 mL g À1 . These results are in parallel to the findings of a previous work carried out by the author (15), in which the fission products 134 Cs and 85 Sr were the studied radioisotopes. However, the results herein are opposed to the data reported by Dyer and Jozefowicz (4) who investigated the interference effect of potassium and sodium ions for the sorption of thorium on the most popular natural zeolites, viz., clinoptilolite and the Eastgate mixture of mordenite and clinoptilolite, at pH 2.…”

“…The diffractograms of antimonysilicates matched to that obtained in previous work (10,15), showing a structure similar to hydrous antimony pentoxide (21,22) (antimonic acid, Sb 2 O 5 Á 4H 2 O), typical of a pyrochlore-type with characteristic peaks at ca. 6.00 and 3.13 Å .…”

“…Previous work by the author illustrates the superior uptake behavior of birnessite for uranium (15) and other radioisotopes present in radioactive waste effluents (10,11) in comparison to titanosilicates (16,17) and antimonysilicate (18). The research, herein, describes the sorption efficiency of birnessite and antimonysilicate materials and their M-derivatives (where M ¼ H, Na, K, and Ca) to take up 234 Th in four different media, representing chemical conditions in waste streams.…”

Characterization of Plutonium, Neptunium, Strontium on Manganese Solids from Permanganate Reduction

“…Layered structures often contain interlayer cations, which can be displaced by other sorbing ions such as the actinides. 16 Layered structures may exhibit some corner-sharing behavior, which gives them more three-dimensional structures than the two-dimensional structures that exist for solids with only edge-linked Mn octahedra.…”

Pre-concentration of naturally occurring radionuclides and the determination of 212Pb from fresh waters

“…Uptake of uranium was above 90% for pH 3e8 (cation adsorption), with decreased adsorption at higher pH attributable to hydrolysis and the formation of mononuclear and polynuclear species (Al-Attar and Dyer, 2002). Thorium uptake was above 90% at pH 2e6, with significant precipitation losses at higher pH.…”