The influence of the dry ashing procedure on the correctness of Pb determination in lichens and mosses.

Mosses and lichens are often used to assess atmospheric deposition of Pb. The most widely used method for determining this isotope is gamma spectrometric analysis. There is often a need to enhance the sensitivity of the method, which can be achieved by pre-concentrating Pb.

Particulate matter from water moss of a large Siberian river: Morphometric, mineral, elemental and radionuclide composition.

Particulate matter trapped by tufts of water moss Fontinalis antipyretica inhabiting fast flowing waters of the Yenisei River (Siberia, Russia) contaminated with artificial radionuclides has been studied as a potential monitor of radioactive releases to the river. Particulate matter, which was removed from wet tufts of water moss of the Yenisei by rinsing them in water, constituted at least 38% of bulk dry weight of the moss biomass sample and was similar in the contents of chemical elements, minerals, organic matter, and artificial radionuclides to bottom sediments of the Yenisei. Considerable bulk percentages of artificial radionuclides in the sample of water moss, 77% of Cs, 44% of Co, 41% of Eu, 55% of Eu, 66% of Am, and 34-36% of plutonium were associated with extracellular particles.

New data on mobility of transuranium elements in sediments of the Yenisei River.

The inflow of transuranium elements to the Yenisei River was previously associated with the production of weapons-grade plutonium at the Mining-and-Chemical Combine (MCC, Zheleznogorsk, Russia), but the source of transuranium elements in the River today is fabrication of MOX fuel that started recently at the MCC. The current study presents results of sequential chemical extraction of radionuclides from sediment samples collected in 2014 and 2020 in two areas near the MCC discharge site and compares these results with the data obtained previously by sequential extraction of sediments collected during 1999-2007. Over the study period, the strength of binding of Cs and Co in the Yenisei River sediments was high (up to 100%) and remained so, while the percentages of Am and Eu in residual solids after sequential extraction increased considerably and the percentage of Pu in residual solids decreased in samples from all study areas.

Approaches to the design of efficient and stable catalysts for biofuel reforming into syngas: doping the mesoporous MgAlO support with transition metal cations.

The mesoporous MgAlO support is promising for the design of efficient and stable to coking catalysts for natural gas and biofuel reforming into syngas. This work aims at doping this support with transition metal cations (Fe, Cr, Ti) to prevent the incorporation of Ni and rare-earth cations (Pr, Ce, Zr), loaded by impregnation, into its lattice along with providing additional sites for CO activation required to prevent coking. Doped MgAlMeO (Me = Fe, Ti, Cr) mesoporous supports prepared by the one-pot evaporation-induced self-assembly method with Pluronic P123 triblock copolymers were single-phase spinels.