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Abstract  

Solid-state M-EDTA chelates, where M represents the divalent ions Mg(II), Ca(II), Sr(II) or Ba(II) and EDTA is ethylenediaminetetraacetate anion, were synthesized. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal behaviour of these chelates. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.

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Abstract  

The ash behaviour comprises one major obstacle towards the efficient utilization of municipal solid wastes, (MSW), in incineration plants. The presence of large amounts of inorganic constituents such as alkali and alkali earth metals, chlorine, sulfur and zinc increase significantly the ash reactivity and lead to severe ash-related problems such as fouling, slagging, corrosion and erosion during their thermal treatment. In this paper, the melting behaviour of various ash fractions originating from the incineration of MSW is studied using simultaneous, (DSC/TG), thermal analysis methods. The produced results provide the basis for improved modelling of the ash behaviour during the incineration of MSW.

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Abstract  

The sorption of monovalent ions (cesium, silver, thallium, mercury), bivalent ions (strontium, barium, lead, copper, cobalt, zinc) and polyvalent ions (cerium) on calcium clinoptilolite under dynamic conditions has been studied. Both the dynamic exchange capacities in the different break-through of the ions and the degree of the exchanging ions in sorption of different metal cations have been determined. The good selectivity of calcium clinoptilolite in relation to cesium and strontium is displayed in the presence of sodium. The influence of various factors on the sorption the thermal and radiation treatment of the sorbent, the pH and concentration of solutions, equilibration time, presence of alkali and alkali earth ions deactivating agents—EDTA, citric acid tartaric acid, and boric acid in solution has been studied. The optimum conditions of sorption have been determined. Experiments for the desorption of cesium and strontium have been carried out. The possibility to use calcium clinoptilolite for the purpose of deactivation of radioactive wastes is shown. The better sorption properties of that sorbent, compared to calcium clinoptilolite, can be explained by the higher aluminium content, as well as by a prevalence of calcium and magnesium in its ion exchange complex.

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Abstract  

Ion-chromatography (IC) as well as high performance liquid chromatography (HPLC) techniques have been used as analytical tools for the separation and estimation of some of the relevant metal ions present in the high level liquid waste (HLLW). IC was applied for the estimation of alkali and alkali earth metal ions, viz. Na, Cs, Ba and Sr using methane sulphonic acid as the eluent on a cation exchange column. On the other hand, dynamically modified (with sodium salt of n-octane sulphonic acid) reverse phase HPLC was followed for the estimation of lanthanides viz. La, Pr, Nd and Sm using α-hydroxy isobutyric acid as the eluent on a C-18 column. Sample acidity of 0.01 M HNO3 was optimized for best analytical results. The interferences of one group of metal ions on the quantification of the other group of metal ions were studied. The solvent extraction data (distribution coefficient data) of Na, Cs, Sr, Ba, La, Pr, Nd and Sm from their mixture was obtained by analyses of the aqueous samples before and after extraction with extractants used for actinide partitioning, viz., octyl(phenyl)N,N-diisobutyl carbamoyl methylene phosphine oxide (CMPO), N,N′-dimethyl-N,N′-dibutyl tetradecyl malonamide (DMDBTDMA) and N,N,N′,N′-tetraoctyl diglycolamide (TODGA). The solvent extraction data obtained by IC/HPLC techniques was compared with those obtained by ICP-AES technique. A good agreement between the results of the two techniques validated the present analytical method.

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]. It is well known that typical solid bases, i.e., alkali-earth metal oxides, promote the isomerization of 1-butene, hydrogenation of 1,3-butadiene, aldol condensation of acetone, and Michael addition of methyl crotonate [ 1 ]. Although many

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-009-0067-7 . 26. Tarasevich , YI , Aksenenko , EV . 2001 . Quantum chemical modelling of ion exchange for alkali earth cations localised in interlayer structural gaps of layer silicate montmorillonite . Colloids Surf A

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.10.003 . 5. Gluhoi , AC , Bogdanchikova , N , Nieuwenhuys , BE 2005 Alkali (earth)-doped Al 2 O 3 catalysts for the total oxidation of propene . J Catal 232 : 96 – 101 10.1016/j.jcat.2005

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Thermal degradation of rice husks on a pilot plant

Utilization of the products as adsorbents for oil spill cleanup

Journal of Thermal Analysis and Calorimetry
Authors: S. Genieva, S. Turmanova, A. Dimitrov, P. Petkov, and L. Vlaev

acid—3.27% and d -galactose—2.37% [ 4 – 6 ]. The chemical analysis of the inorganic part in rice husks showed that the main component is amorphous silica and small amount from some oxides of alkali, alkali earth metals, aluminium, and iron. These husks

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