Odstraňování rtuti z kyselých roztoků chloridu rtuťnatého sorbenty připravenými katalyzovanou vulkanizací rostlinných olejů

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

Substantial Improvement of High Temperature Strength of New-Generation Nano-Oxide-Strengthened Alloys by Addition of Metallic Yttrium

Oxide-dispersion-strengthened (ODS) Fe-Al-Y2O3-based alloys (denoted as FeAlOY) containing 5 vol. % of nano-oxides have a potential to become top oxidation and creep-resistant alloys for applications at temperatures of 1100–1300 °C. Oxide dispersoids cause nearly perfect strengthening of grains; thus, grain boundaries with limited cohesive strength become the weak link in FeAlOY in this temperature range. One of the possibilities for significantly improving the strength of FeAlOY is alloying with appropriate elements and increasing the cohesive strength of grain boundaries. Nearly 20 metallic elements have been tested with the aim to increase cohesive strength in the frame of preliminary tests. A positive influence is revealed for Al, Cr, and Y, whereby the influence of Y is enormous (addition of 1% of metallic Y increases strength by a factor of 2), as it is presented in this paper.

Assessment of contamination level of a Tanzanian river system with respect to trace metallic elements and their fate in the environment

The quality of water and sediments from a marginally-studied river was investigated with respect to As, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn including their fractionation behavior and environmental risk. Samples were collected along the Kou River that flows across two districts in the Manyara region of Tanzania. The leaching behavior of Fe was studied using sequential extraction fractionation and kinetics approach. The Kou water failed to meet the irrigation, aquatic, and biological life standards with respect to one of more trace metallic elements (TMEs). Fe concentration in the river water ranged from 4.1 to 5.38 mg/L exceeding all the three standards. Six pollution indices were applied to assess the contamination and ecological risks of the nine trace metallic elements in the sediments. Overall, the metals were found to moderately contaminate the sediments. Cr, Fe, and Mn fell under the ‘severely polluted’ sediment quality class. Fe was the only metal that was found to significantly pollute both the river water and sediments. The Fe fractions in the sediments were in the order of residuals>Fe-Mn bound>organic bound>carbonate bound>water soluble>ion exchangeable. 7.8% of the total Fe content was bioavailable with a low potential to leach from the sediments. Under natural conditions, the sharpest release of the non-residual mobile fractions of Fe were identified to occur within the first 24 hours with the maximum Fe leached being 0.14% on the 12th day. None of the metals in the sediments were found with a potential to pose ecological risk.

Synthesis and Properties of (Bi, Cd)-doped CuMn2O4 thin films by sol-gel dip-coating method

The present work is carried out within the framework of a research project launched within the physical engineering laboratory at the University of Tiaret in Algeria. The objective is to optimize the conditions for producing thin films of pure spinel oxides doped with different metallic elements. Thus, in this part, we prepared thin films of pure CuMn2O4 and doped with Bi and Cd at rates of 6 and 9% by the sol-gel Dip-coating method. The materials obtained exhibit acceptable crystallinity, excellent optical transmittance with bandgap energies of between 1.64 eV and 1.9 eV and good electrical conductivity.

Lichens (Xanthoria parietina) - Bio-Indicators for Sulphur and Metallic Elements for Pollution Investigation in Riga City

The aim of the research was to investigate the pollution level of sulphur and metallic elements in Riga city (Freeport of Riga, Kundziņsala, Mežaparks) by using foliose lichens (Xanthoriaparietina) as a bio-indicators. Obtained results show that the Freeport of Riga is the most polluted area comparing with other neatest places in Riga city, Kundziņsala and Mežaparks. Evaluate a washing effect, obtained results shows that lichen thallus contains about 50 % of total amount of sulphur and investigated elements as dust particles on the surface of lichens.

Variations of some Metallic Elements in Different Parts of Lingonberries (Vaccinium vitis-idaea L.)

The aim of the research was to evaluate the content of metallic elements in different parts of lingonberries (Vaccinium vitis-idaea L.) depending on their place of growth and evaluate the transfer factor values from between different parts of plants (fine roots, leaves, berries). Obtained results show that there are no significant differences between the content of Fe, Cu, Zn and K, and there are similar element transfer factors between different parts of lingonberries independent from which site the samples are taken.

A Comprehensive Study on the Dynamic Change of Thermal Behavior During Lignocellulose Pyrolysis Catalyzed by Plant-Rich Metallic Elements

Evaluating the pyrolysis of lignocellulose via theoretical and computational approaches is of great importance for the efficient utilization of biomass. In this work, the dynamic changes in physicochemical properties of eucalyptus and bamboo during plant-rich metallic element-catalyzed pyrolysis process were investigated, and their thermal decomposition behaviors were explored by kinetic analysis. Results showed that the metal absorption capacity and thermal stability of eucalyptus were better than those of bamboo. The temperatures corresponding to the initial devolatilization and the highest weight loss value of eucalyptus/bamboo decreased in the catalysis order of Mg > Fe > Ca > Cu > K > Na. Fourier-transform infrared (FT-IR) results showed that the thermal stability of ester bond of glucuronoarabinoxylan was higher than that of acetyl groups. The maximum weight loss rate could be observed for samples with the lowest metal-loaded concentration (5%). Moreover, Mg and Fe presented the better catalytic performance for facilitating the lignocellulose pyrolysis in comparison with other investigated metallic elements.