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2. Redox-Tunable Polycationic Polymers for Environmental ApplicationsTina Skorjanc, Goinda Das, Selbi Nuryyeva, Thirumurugan Prakasam, Ali Trabolsi, 2017, published scientific conference contribution abstract Keywords: covalent polymers, viologen, redox chemistry, pollutant removal, dye adsorption, iodine capture
Published in RUNG: 10.09.2020; Views: 3793; Downloads: 0
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4. Microwave-assisted synthesis of a viologen-based covalent organic polymer with redox-tunable polarity for dye adsorptionGobinda Das, Tina Škorjanc, Thirumurugan Prakasam, Selbi Nuryyeva, John-Carl Olsen, Ali Trabolsi, 2017, original scientific article Keywords: viologen, microwave synthesis, phosphazene, dye adsorption, redox chemistry
Published in RUNG: 02.09.2020; Views: 3771; Downloads: 0
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5. Variations in U concentrations and isotope signatures in two Canadian lakes impacted by U mining: A combination of anthropogenic and biogeochemical processesWei Wang, Duc Huy Dang, Breda Novotnik, Thai T. Phan, R. Douglas Evans, 2019, original scientific article Abstract: Temporal and vertical variations in uranium (U) concentrations and U isotope (δ238U, ‰) signatures were
examined in sediment cores collected seven times over a one year period, from two lakes in Ontario, Canada,
which are contaminated with U by historical mining activities. Bow Lake is holomictic, experiencing seasonal
anoxia, while the sediments of meromictic Bentley Lake are permanently anoxic. Average annual peak concentrations
of U in Bow Lake subsurface sediments were approximately 300 μg L−1 and 600 μg g−1 in porewater
and bulk sediments, respectively. Similar ranges of concentrations (900 μg L−1 and 600 μg g−1, respectively)
were observed in Bentley Lake sediments. The exceedingly high levels of U observed in the porewaters of both
lakes, as well as the seasonal variability in U levels, challenge the traditional paradigm regarding U chemistry,
i.e., that reduced U(IV) should be insoluble under anoxic conditions.
The average annual δ238U ‰ values at the sediment-water interface of both lakes were similar (i.e.,
0.47 ± 0.09‰ and 0.50 ± 0.16‰, relative to IRMM-184). The deep sediments in both Bentley Lake and Bow
Lake record U isotope composition with a typical fractionation of 0.6‰ relative to the surface water, confirming
authigenic U accumulation, i.e., negligible contribution of particulate material from the tailings. Also, the δ238U
values in porewater have an average offset of ca. −0.1‰ relative to bulk sediments in anoxic zones and are
reversed in the oxic sediment layer.
Keywords: Uranium
Isotope composition
Uranium tailings
Biogeochemical cycling
Redox chemistry
Published in RUNG: 09.10.2019; Views: 4410; Downloads: 0
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