Fate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite

The impact on U(VI) adsorbed to lepidocrocite (gamma-FeOOH) and hematite (alpha-Fe2O3) was assessed when exposed to aqueous sulfide (S(II)(aq)) at pH 8.0. With both minerals, competition between S(-II) and U(VI) for surface sites caused instantaneous release of adsorbed U(VI). Compared to lepidocrocite, consumption of S(-II)(aq) proceeded slower with hematite, but yielded maximum dissolved U concentrations that were more than 10 times higher, representing about one-third of the initially adsorbed U. Prolonged presence of S(-II)(aq) in experiments with hematite in combination with a larger release of adsorbed U(VI), enhanced the reduction of U(VI): after 24 h of reaction about 60-70% of U was in the form of U(W), much higher than the 2S% detected in the lepidocrocite suspensions. X-ray absorption spectra indicated that U(IV) in both hematite and lepidocrocite suspensions was not in the form of uraninite (UO2). Upon exposure to oxygen only part of U(IV) reoxidized, suggesting that monomeric U(W) might have become incorporated newly formed iron precipitates. sulfidization of Fe oxides can have diverse consequences for U mobility: in short-term, desorption of U(VI) increases U mobility, while reduction to U(W) and its possible incorporation in Fe transformation products may lead to long-term U immobilization.European Union's European Atomic Energy Community's (Euratom) Seventh Framework Programme FP7 [212287

Coming full circle: Differential empowerment in the EU accession process

The EU accession process brings a profound transformation not only to candidate countries’ institutions and policies, but also to the political opportunity structure in place, creating new possibilities for previously marginalised actors. Studying the differential empowerment of NGOs throughout the Croatian accession process, this paper makes two related claims: first, differential empowerment depends crucially on domestic actors’ awareness for and ability to use new opportunities to their advantage. Second, an overreliance on EU leverage poses important temporal and substantive limits on NGO empowerment and leads to a rapid decline of their relevance in the post-accession phase. I argue that a more sustainable shift in the domestic power balance would require both the EU and domestic civil society actors to place more emphasis on fostering improved practices of civil society inclusion in domestic policymaking settings throughout the accession process

Rethinking “democratic backsliding” in Central and Eastern Europe – looking beyond Hungary and Poland

This essay introduces contributions to a special issue of East European Politics on “Rethinking democratic backsliding in Central and Eastern Europe”, which seeks to expand the study of democratic regression in CEE beyond the paradigmatic cases of Hungary and Poland. Reviewing these contributions, we identify several directions for research: 1) the need to critique “democratic backsliding”, not simply as a label, but also as an assumed regional trend; 2) a need to better integrate the role of illiberal socio-economic structures such as oligarchical structures or corrupt networks; and 3) a need to (re-)examine the trade-offs between democratic stability and democratic quality. We also note how insights developed researching post-communist regions such as Western Balkans or the post-Soviet space could usefully inform work on CEE backsliding. We conclude by calling for the study of CEE democracy to become more genuinely interdisciplinary, moving beyond some narrowly institutionalist comparative political science assumptions

(Table 2) Contents of U, P2O5, CO2, and TOC in phosphorites from Pacific seamounts

Uranium content of in phosphorites from Pacific seamounts does not exceed 10ppm; it is significantly lower than in phosphorites from submarine continental margins and deposits on land. Phosphate is not the main carrier of uranium, which is inhomogeneously distributed in ferromanganese hydroxide-, phosphate-, silicate- and carbonate materials. Uranium associated with phosphate is not isomorphic admixture. Uranium occurs in rocks in fine particles of unknown composition. Ultramicroscopic inclusions of U(IV) oxides have been also found

(Table 1) Results of X-ray radiographic analyses of authigenic phosphorites from the Southwest Africa shelf

In the biologically productive area on the Southwest Africa shelf a current process of diagenetic phosphorite formation occurs. Remains of phytoplankton are the main source of phosphorus in host bottom sediments. Phosphorus concentrates in nodules due to its redistribution in bottom sediments and precipitation from interstitial waters. Accumulation of the phosphate nodules, as well as of scattered fish bone debris in sediments occurs at sudden change in hydrological conditions and removal of fine sediment fractions due to increased bottom currents or during transgressions

Chemical composition of bottom sediments from the Discovery Deep, Red Sea rift zone

Hot brines in depressions of the central Red Sea contain thousands of times more iron, manganese and other metals than . After removal of salts, approximately half of sediments from these depressions consists of iron hydroxides and they are enriched in zinc, copper, lead and molybdenum. Hydrothermal deposits with the same complex of metals, located along the coast of the Red Sea, are correlated with faults and may be due to occurrences of Tertiary volcanism. Brines of similar composition are known in the Cheleken Peninsula. Certain geological and geochemical data indicate that such brines are of relatively deep origin