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1.
Wolfgang Hummel 《Monatshefte für Chemie / Chemical Monthly》2008,139(5):459-480
Equilibrium thermodynamics is one of the pillars which support safety analyses of repositories for radioactive waste. The research summarized in this review deals with approaches to resolve the problems related to thermodynamic equilibrium constants and solubility of solid phases in the field of radioactive waste management. The results have been obtained at the Paul Scherrer Institut between 1995 and 2005 and comprise the scientific basis of the author’s habilitation thesis in the field of nuclear environmental chemistry. The topics are grouped according to three different levels of problem solving strategies: (1) Critical and comprehensive reviews of the available literature, which are necessary in order to establish a reliable chemical thermodynamic database that fulfils the requirements for rigorous modeling of the behavior of the actinides and fission products in the environment. (2) In many case studies involving inorganic and simple organic ligands a serious lack of reliable thermodynamic data is encountered. There, a new modeling approach to estimate the effects of these missing data was applied. This so called “backdoor approach” begins with the question, “What total concentration of a ligand is necessary to significantly influence the speciation, and hence the solubility, of a given trace metal?” (3) In the field of natural organics, mainly humic and fulvic acids, we face an ill-defined problem concerning the molecular structure of the ligands. There, a pragmatic approach for performance assessment purposes was applied, the “conservative roof” approach, which does not aim to accurately model all experimental data, but allows estimates of maximum effects on metal complexation by humic substances to be calculated. 相似文献
2.
Elfriede Simon M. G. Weller Reinhard Niessner 《Analytical and bioanalytical chemistry》1998,360(7-8):824-826
The aim of the described method was the characterization of a “atrazine-mercaptopropionic acid” humic acid conjugate, which
was required for the calibration of immunoassays to determine bound residues. In order to estimate the amount of bound triazine,
an oxidative nucleophilic substitution reaction of the covalently linked “atrazine-mercaptopropionic acid” to a new triazine
derivative “atrazine-methoxyethanol” was performed. This cleavage product was quantified by gas chromatography. The conditions
for this cleavage procedure were optimized and applied to the “atrazine-mercaptopropionic acid” humic acid conjugate and to
a humic acid blank. The amount of bound “atrazine-mercaptopropionic acid” was calculated to 16.6 ± 2.5 μmol triazine per gram
humic acid, which is equivalent to 0.39 ± 0.07% atrazine.
Received: 7 August 1997 / Accepted: 12 September 1997 相似文献
3.
Multivariate statistical analysis of sediment data (information matrix 123 × 16) from the Gulf of Mexico, USA shows that
the data structure is defined by four latent factors conditionally called “inorganic natural”, “inorganic anthropogenic”,
“bioorganic” and “organic anthropogenic” explaining 39.24%, 23.17%, 10.77% and 10.67% of the total variance of the data system,
respectively. The receptor model obtained by the application of the PCR approach makes it possible to apportion the contribution
of each chemical component for the latent factor formation. A separation of the contribution of each chemical parameter is
achieved within the frames of “natural” and “anthropogenic” origin of the respective heavy metal or organic matter to the
sediment formation process. This is a new approach as compared to the traditional “one dimensional” search with a limited
number of preliminary selected tracer components. The model suggested divides natural from anthropogenic influences and allows
in this way each participant in the sediment formation process to be used as marker of either natural or anthropogenic effects.
Received: 20 March 1999 / Revised: 1 June 1999 / Accepted: 3 June 1999 相似文献
4.
I. Stanimirova S. Tsakovski V. Simeonov 《Fresenius' Journal of Analytical Chemistry》1999,365(6):489-493
Multivariate statistical analysis of sediment data (information matrix 123 × 16) from the Gulf of Mexico, USA shows that
the data structure is defined by four latent factors conditionally called “inorganic natural”, “inorganic anthropogenic”,
“bioorganic” and “organic anthropogenic” explaining 39.24%, 23.17%, 10.77% and 10.67% of the total variance of the data system,
respectively. The receptor model obtained by the application of the PCR approach makes it possible to apportion the contribution
of each chemical component for the latent factor formation. A separation of the contribution of each chemical parameter is
achieved within the frames of “natural” and “anthropogenic” origin of the respective heavy metal or organic matter to the
sediment formation process. This is a new approach as compared to the traditional “one dimensional” search with a limited
number of preliminary selected tracer components. The model suggested divides natural from anthropogenic influences and allows
in this way each participant in the sediment formation process to be used as marker of either natural or anthropogenic effects.
Received: 20 March 1999 / Revised: 1 June 1999 / Accepted: 3 June 1999 相似文献
5.
Hassan NM Murimboh JD Sekaly AL Mandal R Chakrabarti CL Grégoire DC 《Analytical and bioanalytical chemistry》2006,384(7-8):1558-1566
Kinetic speciation of nickel, aluminium, and iron in fresh water has been investigated by cascade ultrafiltration followed by competing ligand exchange of the ultrafiltered fractions. Graphite furnace atomic absorption spectrometry was used to measure the kinetics of metal complex dissociation. Dissolved metal species were fractionated by cascade ultrafiltration. Metal speciation in each ultrafiltered fraction was then characterized as free metal ions, “labile” metal complexes (with dissociation rate constants ≥10−3 s−1), “slowly labile” metal complexes (with dissociation rate constants >10−6 s−1), and “inert” metal complexes (with dissociation rate constants <10−6 s−1). The experimental results were compared with the predictions of a computer-based equilibrium speciation model, the Windermere humic aqueous model (WHAM) V. Cascade ultrafiltration coupled with kinetic speciation of the metal species in each molecular weight cut-off (MWCO) fraction provided a more comprehensive picture and insight into the physical and the chemical characteristics of the metal species than either ultrafiltration or measurement of dissociation kinetics alone. 相似文献
6.
Characterization of groundwater humic and fulvic acids of different origin by GPC with UV/Vis and fluorescence detection 总被引:1,自引:0,他引:1
R. Artinger G. Buckau J. I. Kim S. Geyer 《Fresenius' Journal of Analytical Chemistry》1999,364(8):737-745
Gel permeation chromatography (GPC) was applied for recognizing the origin of groundwater humic and fulvic acids. GPC was
performed with Fraktogel TSK HW-50 in 0.1 M NaCl, pH 8.5 (0.05 M phosphate buffer), 1 mM EDTA, with 10% by volume methanol
added. Humic substances from groundwaters and sediments of four different aquifer systems in Germany were isolated, purified
and characterized. Both UV/Vis and fluorescence detection were applied. UV/Vis detection was found to be more powerful in
identifying differences between the various humic and fulvic acids. The four aquifer systems investigated (“Gorleben”, “Fuhrberg”,
“Franconian Albvorland” and “Munich”) differed from one another with respect to hydrological and geochemical conditions. The
results showed that the GPC-elution behavior reflects the geochemical environment and origin (source material and generation
process) of aquatic humic and fulvic acids.
Received: 17 November 1998 / Revised: 18 March 1999 / Accepted 23 March 1999 相似文献
7.
Vasil Simeonov Costel Sarbu Desire-Luc Massart Stefan Tsakovski 《Mikrochimica acta》2001,137(3-4):243-248
A data set (48×19) consisting of Danube river water analytical data collected at Galati site, Romania, during a four-year
period has been treated by principal components analysis (PCA). The PCA indicated that seven latent factors (“hardness”, “biochemical”,
“waste inlets”, “turbidity”, “acidity”, “soil extracts” and “organic wastes”) are responsible for the data structure and explain
over 80 % of the total variance of the system. Its complexity is further proved by the application of multiple linear regression
analysis on the absolute principal components scores (APCS) where the contribution of each natural or anthropogenic sources
in the factor formation is shown. The apportioning makes clear that each variable participates to a different extent to each
source and, in this way, no pure natural or pure anthropogenic influence could be determined. No specific seasonality for
the variables in consideration is found.
Received January 24, 2001. Revision July 6, 2001. 相似文献
8.
9.
Aleksander Astel Grażyna Głosińska Tadeusz Sobczyński Leonard Boszke Vasil Simeonov Jerzy Siepak 《Central European Journal of Chemistry》2006,4(3):543-564
The sustainable development rule implementation is tested by the application of chemometrics in the field of environmental
pollution. A data set consisting of Cd, Pb, Cr, Zn, Cu, Mn, Ni, and Fe content in bottom sediment samples collected in the
Odra River (Germany/Poland) is treated using cluster analysis (CA), principal component analysis (PCA), and source apportionment
techniques. Cluster analysis clearly shows that pollution on the German bank is higher than on the Polish bank. Two latent
factors extracted by PCA explain over 88 % of the total variance of the system, allowing identification of the dominant “semi-natural”
and “anthropogenic” pollution sources in the river ecosystem. The complexity of the system is proved by MLR analysis of the
absolute principal component scores (APCS). The apportioning clearly shows that Cd, Pb, Cr, Zn and Cu participate in an “anthropogenic”
source profile, whereas Fe and Mn are “semi-natural”. Multiple regression analysis indicates that for particular elements
not described by the model, the amounts vary from 4.2 % (Mn) to 13.1 % (Cr). The element Ni participates to some extent to
each source and, in this way, is neither pure “semi-natural” nor pure “anthropogenic”. Apportioning indicates that the whole
heavy metal pollution in the investigated river reach is 12510.45 mg·kg−1. The contribution of pollutants originating from “anthropogenic sources” is 9.04 % and from “semi-natural” sources is 86.53
%. 相似文献
10.
Multivariate statistical assessment of polluted soils 总被引:9,自引:0,他引:9
Vasil Simeonov Juergen Einax Stafan Tsakovski Joerg Kraft 《Central European Journal of Chemistry》2005,3(1):1-9
This study deals with the application of several multivariate statistical methods (cluster analysis, principal components
analysis, multiple regression on absolute principal components scores) for assessment of soil pollution by heavy metals. The
sampling was performed in a heavily polluted region and the chemometric analysis revealed four latent factors, which describe
84.5 % of the total variance of the system, responsible for the data structure. These factors, whose identity was proved also
by cluster analysis, were conditionally named “ore specific”, “metal industrial”, “cement industrial”, and “steel production”
factors. Further, the contribution of each identified factor to the total pollution of the soil by each metal pollutant in
consideration was determined. 相似文献
11.
S. V. Larionov 《Russian Journal of Coordination Chemistry》2012,38(1):1-23
Some problems of the chemistry of coordination metal compounds with chiral ligands based on natural organic compounds, especially
terpenes, are generalized. The results on the synthesis and study of the structure and properties of the chiral transition
metal complexes with several groups of new “hybrid” ligands based on monoterpenes pinene, (+)-3-carene, and limonene and sesquiterpene
caryophyllene are considered. 相似文献
12.
V. A. Nikanorov O. L. Tok S. G. Novikov S. V. Sergeev E. V. Vorontsov I. D. Gridnev D. V. Zverev A. T. Lebedev 《Russian Chemical Bulletin》1997,46(2):350-354
Three approaches to the synthesis ofN-substituted imino-, hydrazono-, and azino-2,5-cyclohexadienylidene systems based on reactions of 4-methyl-4-trichloromethylcyclohexa-2,5-dienone
with aminophenols and hydrazones and condensation of hydrazones ofpara-semiquinoid ketones with carbonyl compounds, including that of the ferrocene series, were realized. The latter reaction,
when applied to 3,6-dibromophenanthrene-9, 10-quinone, was accompanied by quantitative aromatizational molecular rearrangement
with the elimination of the CCl3 group. Using Rh1 complexes as an example, it was shown that the heteroorganic ligands obtained can be used for the synthesis of mixed-ligand
metallocomplexes with triple coordination of the metal atom including simultaneous metal-ligand interactions of the n-, π-,
and σ-types.
The principle of metal-ligand “cascade” appeared as a result of the generalization of two new phenomena of organometallic
sereodynamics, which we have found recently2,3 and have called oxidative and reductive redox-rotation. In the “cascade”, type1 (“metal-ligand-metal”) or type2 (“ligand-metal-ligand”) metallocomplexes, one or several coordinated metal ligand”) metallocomplexes, one or several coordinated
metal atoms capable of concertedly and reversibly changing their valence in the course of intramolecular conformational transformation
are in positions of mutual conjugation.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 363–367, February, 1997. 相似文献
13.
The environmetrical analysis carried out has indicated that the short-term water quality survey may give a very important
information on the latent factors influencing the water quality of Yantra river basin. The principal components analysis carried
out reveals that at least four principal components are necessary for multivariate statistical modeling of the water quality
– combination of natural and anthropogenic influences (“mixed” factor) reflecting parameters such as water hardness, marine
influence, organic pollution; typical anthropogenic influences (“anthropogenic” factor) explaining the metal contamination
of the river water; everyday wastes, usually N-containing pollutants such as nitrates, nitrites or ammonia, form the “N-containing
wastes” factor and a “temperature” factor formed by typical physical parameters such as water and air temperature.
The formation of these special features of the river waters from Yantra basin is also confirmed by the results of cluster
analysis (variable clustering) where the content of the significant clusters of the variables is the same as the content of
the principal components modeling over 75% of the total variance of the system. Additionally, the cluster analysis of the
objects has proved that the water quality during both sampling traverses is very stable and reproducible. Few exceptions are
observed due to momentary local pollution in an industrial area along the river stream. Comparison with standard requirements
for water quality has indicated that the Yantra river waters are of high quality and could be used after minor pretreatment
as potable water sources.
The environmetrical approaches applied reveal a specific information concerning the river water quality. In this way the ecological
problem treated has not a local importance but suggests a strategy for estimation of similar ecosystems in global sense.
Received July 30, 1998. Revision June 1, 1999. 相似文献
14.
V. E. Kuzmin I. S. Rublev D. V. Naroditskii E. V. Gapon 《Journal of Structural Chemistry》1995,36(5):798-802
New types of ligands for spherical ions have been designed as part of the molecular design strategy for supramolecular compounds.
In particular, symmetric conformers of macrocycles, built of −(CH2)n−O−(n=3,4,5) fragments, which envelope the spherical ion in a complementary way, have been constructed. Alos, new types of
“bracelentands” with different, “hardening” fragments are suggested. Using the molecular mechanics methods, the selectivity
of complex formation of the ligands with respect to alkaline metal ions has been investigated.
A. V. Bogatskii Physicochemical Institute, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 5, pp. 879–883, September–October, 1995.
Translated by L. Smolina 相似文献
15.
N. E. Kuz’mina E. S. Osipova V. S. Kuz’min V. B. Sitnikov 《Russian Chemical Bulletin》2008,57(6):1277-1284
Analysis of experimental data on the correlation of agonistic and antagonistic properties of molecules of the opiate receptor
(OR) ligands of various structural classes and the use of the method of superposition of three-dimensional structures allowed
one to single out two regions of the opiate pharmacophore in which hydrophobic interactions are implemented fixing molecules
of the OR ligands close to the intercellular membrane and transforming them into “pure” agonists. A set of geometrical parameters
characterizing arrangement of these regions in space is defined. This set can be used as a criterion for evaluation of the
correlation of agonistic and antagonistic properties in the modeling of new types of OR ligands.
For Part 1, see Ref. 1.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1253–1260, June, 2008. 相似文献
16.
Galina Sadovska Ivan Kron Erich Königsberger 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):787-790
Summary. The solubility of anhydrous uric acid was measured in 0.30 mol dm−3 LiCl solutions as a function of hydrogen ion concentration at 25 and 37°C. No influence of the lithium ion on the solubility
of uric acid was detected. The “litholytic” effect of lithium reported in literature can possibly be explained by the higher
solubility of lithium hydrogenurate as compared to other alkali metal hydrogenurates.
Corresponding author. E-mail: koenigsb@chem.murdoch.edu.au
Received November 21, 2002; accepted December 10, 2002
Published online April 7, 2003
RID="a"
ID="a" Dedicated to Professor Heinz Gamsj?ger on the occasion of his 70th birthday 相似文献
17.
O. Manero J. F. A. Soltero J. E. Puig V. M. González-Romero 《Colloid and polymer science》1997,275(10):979-985
In this work, the linear viscoelastic properties of cetyl-trimethylammonium tosilate–water system are predicted by the modeling
of the relaxation spectrum. The modeled spectrum of relaxation times is of the “wedge-box” type where the “wedge” portion
is located at the short-time scale of relaxation times and the “box” part covers the long-time scale. The linear viscoelastic
properties are calculated through the exact relationships with the suggested spectrum. Agreement between the calculated expressions
and experimental data of the moduli and the stress relaxation function is found. Comparison is also made with predictions
of the empirical expressions of the Cole–Cole and the Williams–Watts models.
Received: 17 December 1996 Accepted: 1 July 1997 相似文献
18.
Detailed information on the geochemical behavior of radioactive and toxic metal ions under environmental conditions (in geological
matrices and aquifer systems) is needed in order to assess the long-term safety of waste repositories. This includes knowledge
of the mechanisms of relevant geochemical reactions, as well as associated thermodynamic and kinetic data. Several previous
studies have shown that humic acid can play an important role in the immobilization or mobilization of metal ions due to complexation
and colloid formation. In our project we investigate the complexation behavior of (purified Aldrich) humic acid and its influence
on the migration of the lanthanides europium and gadolinium (homologs of the actinides americium and curium) in the ternary
system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) under almost natural conditions. Capillary electrophoresis
(CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was hyphenated with a homemade interface to inductively
coupled plasma mass spectrometry (ICP–MS, VG Elemental PlasmaQuad 3) giving a system that is highly sensitive to the rare-earth
element species of europium and gadolinium with humic acid. The humic acid used was also halogenated with iodine, which acted
as an ICP–MS marker. To couple CE to ICP–MS, a fused silica CE capillary was flexibly fitted into a MicroMist 50 μl nebulizer
with a Cinnabar cyclonic spray chamber in the external homemade interface. The chamber was chilled to a temperature of 4 °C
to optimize the sensitivity. 200 ppb of cesium were added to the CE separation buffer so that the capillary flow could be
observed. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within
the interface in order to get a fluid throughput high enough to maintain continuous nebulization. Very low detection limits
were achieved: 125 ppt for 153Eu and 250 ppt for 158Gd. Using this optimized CE–ICP–MS coupling system it was possible to quantify metal concentrations from the detection limit
up to approximately 1 ppm (the linear range). This set-up was used to separate metal/humic acid-species in a 100 mM acetic
acid/10 mM acetate buffer system. Using humic acid as the complexing ligand, uncomplexed metal ion species could be separated
from metal–humate complexes on a time-resolved scale.
相似文献
19.
The surface diffusion of physical-vapour-deposited metal atoms on thermoplastic polymer substrates was investigated. In accordance
with the hypothesis of the “classical” atomistic diffusion model, diffusion coefficients are derived from a Monte Carlo simulation.
Because the “classical” atomistic diffusion model neglects the desorption of the metal atoms, the absolute diffusion data
obtained in our investigations should only be considered as rough estimates. It is more the intention of our work to present
relative values in order to correlate the metal surface diffusion on polymer substrates with their physical states (morphologies
and surface dynamics). As expected, the diffusivity of metal atoms is strongly influenced by the chemical affinity (“reactivity”)
between the metal atoms and the polymer substrate. Furthermore, the diffusivity strongly depends on the physical state of
the polymer substrate. On polymer surfaces above the glass-transition temperature the surface diffusivity of metal atoms is
1 order of magnitude higher than the diffusivity below the glass-transition temperature.
Received: 9 April 1999/Accepted in revised form: 21 October 1999 相似文献
20.
Davor Margetić Ronald N. Warrener Doug N. Butler David Officer 《Theoretical chemistry accounts》2007,117(2):239-245
A computational study of a series of space separated bis-porphyrin “molecular tweezers” using semiempirical (AM1) and DFT
(B3LYP and PBE1PBE) methods has been carried out. It was found that polynorbornane bis-porphyrin systems are significantly
less rigid than previously thought. The variation of the metal–metal separation distance between the two porphyrin centers
does not cause a significant energy change thus enabling these molecules to easily adjust to the optimal coordination distance
required for complexation by various bidentate 4-pyridyl ligands inside the cavity of these “tweezers”.
Article 54, ECCC-10, April 1-30 2005, http://www.eccc.monmouth.edu 相似文献