Search results for "nuclear chemistry"

Modeling of the effect of EDTA on copper(II) biosorption onto Posidonia oceanica waste in batch and fixed-bed systems

2014

Abstract The performance of Posidonia oceanica for copper(II) biosorption in the presence of EDTA was investigated in batch and column experiments. In batch mode, copper(II) uptake in the presence of EDTA was lower than in its absence for the pH range 1.5–6.0. The decrease in the copper(II) uptake, attributed to the change in the chemical speciation of copper(II) with EDTA in solution, was from 71.7 to 58.8 mg/g in the absence and presence of EDTA respectively at pH 6. Column experiments were carried out at 5 and 20 mg Cu(II)/dm 3 and different doses of EDTA. Constant copper(II) leaks were detected in the effluent of the columns. Leak concentrations matched the copper(II)-EDTA complexes’ co…

Spermatocyte chromosome alterations intruncatella subcylindrica (L., 1767) (Mollusca, Mesogastropoda) following exposure to dibutyltin(IV) and tribut…

1992

In order to analyze chromosomes for possible numerical and structural alterations in response to exposure to organotin(IV) compounds, gastropod Truncatella subcylindrica specimens were treated with dibutyltin(IV) and tributyltin(IV) chloride solutions with different exposure times. Experimental evidence suggests that tributyltin(IV) chloride is more toxic to this organism than dibutyltin(IV) dichloride at low concentrations. Furthermore, the toxicity responses to these organotin(IV) derivatives seem to be proportional to both concentration and exposure time. The following structural lesions have been identified by comparative analysis of spermatocyte chromosomes from untreated specimens and…

Identification of metalloporphyrins extracted from the copper bearing black shale of fore sudetic monocline (Poland)

2006

Abstract Metalloporphyrins were isolated from copper-bearing black shale ores. The shale originates from the Lubin copper mine (Poland). The porphyrins have been extracted by way of a Soxhlet apparatus, and then purified using column chromatography. In order to identify the extracted porphyrins complexes UV–Vis, mass spectrometry and EPR analytical techniques have been used.

Modeling of 137Cs migration in soils using an 80-year soil archive: role of fertilizers and agricultural amendments

2008

An 80-year soil archive, the 42-plot experimental design at the INRA in Versailles (France), is used here to study long-term contamination by 137Cs atmospheric deposition and the fate of this radioisotope when associated with various agricultural practices: fallow land, KCl, NH4(NO3), superphosphate fertilizers, horse manure and lime amendments. The pertinence of a simple box model, where radiocaesium is supposed to move downward by convectional mechanisms, is checked using samples from control plots which had been neither amended, nor cultivated since 1928. This simple model presents the advantage of depending on only two parameters: α, a proportional factor allowing the historical atmosph…

Conversion of Xylose to Furfural over Lignin-Based Activated Carbon-Supported Iron Catalysts

2020

In this study, conversion of xylose to furfural was studied using lignin-based activated carbon-supported iron catalysts. First, three activated carbon supports were prepared from hydrolysis lignin with different activation methods. The supports were modified with different metal precursors and metal concentrations into five iron catalysts. The prepared catalysts were studied in furfural production from xylose using different reaction temperatures and times. The best results were achieved with a 4 wt% iron-containing catalyst, 5Fe-ACs, which produced a 57% furfural yield, 92% xylose conversion and 65% reaction selectivity at 170 &deg

Uptake of actinides by calcium silicate hydrate (C-S-H) phases

2018

Abstract The sorption of actinides (Th, U – Am) was studied in dependence of the solid-to-liquid (S/L) ratio (0.5–20.0 g/L) and the calcium-to-silicon (C:S) ratio. The C:S ratio was varied between 1.80 and 0.70 to simulate the changing composition of the C-S-H phases during cement degradation from high to low C:S ratios. The decrease of the calcium content in the C-S-H phases by time is accompanied by a decrease in pH in the corresponding suspensions from 12.6 to 10.2. X-ray photoelectron spectroscopy (XPS) of the C-S-H phases showed an increasing depletion of Ca on the surface with increasing C:S ratio in comparison to the composition of the solid phase as a whole. The sorption experiments…

Inhibitoren der Korrosion 27 (1). Inhibitoren der Korrosion von Kupfer - Gibt es eine Struktur-Wirkungsbeziehung?

1982

Mehr als 570 Verbindungen der unterschiedlichsten Struktur wurden unter Standardbedingungen im “Schuttelversuch” und pH-statisch auf ihre Korrosionsschutzwirkung gegenuber Kupfer getestet und mit Hilfe eines Computers ausgewertet. Die erhaltenen Ergebnisse stehen relativ haufig in Ubereinstimmung mit Dem “Hart-Weich-Konzept” von Pearson. Eine gezielte Synthese von Inhibitoren, die sich in diesem Konzept orientiert, ist jedoch nicht moglich. Inhibitors of corrosion 27 (1). Inhibitors of the corrosion of copper Does there exist a structure-effect-relation? Over 570 compounds of greatly varying structure have been tested under controlled conditions in agitation and pH-stat experiments designed…

Thallium in Wein — Spurenelement-Vinogramm des Thalliums

1984

Das Ultra-Spurenelement Thallium ist regelmasig in geringsten Gehalten in Wein enthalten, in Rotwein durchschnittlich 0,2 μg Tl/l, mehr als in Weisweinen mit durchschnittlich 0,1 μg Tl/l. Uber Herkunft und Verhalten solcher geringsten Thallium-Gehalte konnen einige Hinweise aus den zusatzlichen Untersuchungen (Boden, Standort, Dungemittel, Einflus der Kellertechnik) gegeben werden. Eine Korrelation von Thallium mit Kalium ist bekannt; es kann aber daruber hinaus gezeigt werden, das ahnlich dem Rubidium gewisse Traubenteile (Beere, Beerenfleisch, Schale) reicher an Thallium sind und auf diese Weise hohere Gehalte, insbesondere in Rotweinen, erklart werden konnen. Geringfugig hohere Thallium-…

Dialysability of Calcium, Iron, and Zinc in Beans, Chick Peas, and Lentils

2002

Studies on coordination compounds—VIII. Syntheses, structural, magnetic, spectral and thermal properties of some cobalt(II), nickel(II) and copper(II…

1995

Abstract The complexes bis[triaqua(2-aminopyrimidine)-μ-sulphato-O,O′-cobalt(II)] dihydrate (1), catena-[diaqua(2(2-aminopyrimidine))-μ-sulphato-O,O′nickel(II)]2-amino-pyrimidine (2), [pentaaqua(2-aminopyrimidine)nickel(II)]sulphate 2-aminopyrimidine (3) and catena-[aqua(2(2-aminopyrimidine))-μ-sulphato-O,O′-copper(II)] dihydrate (4) were prepared, structure determined by X-ray methods and physical properties studied by magnetic, IR, NMR, EPR and reflectance methods. The thermal behaviour was studied by TG and mass spectrometric methods. The results are discussed on a structural basis.