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We have systematically studied the surface properties, such as symmetry energy, neutron pressure, and symmetry energy curvature coefficient for Ne, Na, Mg, Al, and Si nuclei from the proton to neutron drip lines. The coherent density fluctuation model (CDFM) is used to estimate these quantities taking the relativistic mean-field densities as inputs. The Bruckner energy density functional is taken for the nuclear matter binding energy and local density approximation is applied for its conversion to coordinate space. The symmetry energy again decomposed to the volume and surface components within the liquid drop model formalism to the volume and surface parts separately. Before calculating the surface properties of finite nuclei, the calculated bulk properties are compared with the experimental data, whenever available. The NL3* parameter set with the Bardeen-Cooper-Schrieffer (BCS) pairing approach in an axially deformed framework is used to take care of the pairing correlation when needed. The deformed density is converted to its spherical equivalent with a two-Gaussian fitting, which is used as an input for the calculation of weight function in the CDFM approximation. With the help of the symmetry energy, the isotopes [sup.29]F, [sup.28]Ne, [sup.29,30]Na, and [sup.31,35,36]Mg are considered to be within the island of inversion (Han et al. Phys. Lett. B, 772, 529 (2017). doi:10.1016/j.physletb.2017.07.007). Although we get large symmetry energies corresponding to a few neutron numbers for this isotopic chain as expected, an irregular trend appears for all these considered nuclei. The possible reason behind this abnormal behavior of symmetry energy for these lighter mass nuclei is also included in the discussion, which gives a direction for future analysis. Key words: symmetry energy, magic number, binding energy, relativistic mean-field model, coherent density fluctuation model. Nous etudions systematiquement les proprietes des surfaces nucleaires, comme l'energie de symetrie et le coefficient de courbure de l'energie de symetrie pour les noyaux de Ne, Na, Mg, Al et Si, entre la limite de stabilite des protons et celle des neutrons. La modele de la fluctuation de densite coherente (MFDC/CDFM) est utilise pour evaluer ces quantites en prenant les densites en champ moyen relativistes comme donnees d'entree. La fonctionnelle de densite d'energie de Bruckner est retenue comme l'energie de liaison de la matiere nucleaire et une approximation de densite locale est utilisee pour sa conversion aux coordonnees d'espace. L'energie de symetrie decomposee en composantes de volume et de surface dans le formalisme du modele de la goutte liquide donne des parties de volume et de surface separement. Avant de calculer les proprietes de surface de noyaux finis, les proprietes massiques calculees sont comparees aux valeurs experimentales lorsque disponibles. Nous utilisons l'ensembles parametrique NL3* de l'approche Bardeen-Cooper-Schrieffer (BCS) du pairage dans un cadre de deformation axiale pour tenir compte des correlations de pairage lorsque necessaire. La densite deformee est transformee en equivalent spherique a l'aide d'un ajustage numerique a deux gaussiennes, un resultat a son tour utilise comme donnee d'entree pour le calcul de la fonction de poids dans l'approximation MFDC/CDFM. Avec l'aide de l'energie de symetrie, les recents isotopes [sup.29]F, [sup.28]Ne, [sup.29,30]Na et [sup.31,35,36]Mg sont consideres etre sur une ile d'inversion (Han et al. Phys. Lett. B, 112, 529 (2017). doi:10.1016/j.physletb.2017.07.007). Meme si, tel qu'attendu, nous obtenons de larges valeurs de l'energie de symetrie correspondant a un petit nombre de neutrons pour cette chaine d'isotopes, une tendance irreguliere apparait pour tous ces nuclides. La possible raison derriere ce comportement anormal de l'energie de symetrie pour ces masses nucleaire plus legeres est incluse dans la discussion ci-dessous, qui donne une direction pour de futures analyses. [Traduit par la Redaction] Mots-cles : energie de symetrie, nombre magique, energie de liaison, modele relativiste de champ moyen, modele de fluctuation de densite coherente., 1. Introduction The surface property of a nucleus is one of the pivotal quantities to determine the structural information of finite and infinite nuclear matter (NM) at isospin asymmetry. The [...]

The interfacial distribution of a number of organic photometric reagents in a water-potassium bis(alkylpolyoxyethylene)phosphate (oxyphos B)-ammonium sulphate splitting system is studied. It is found that alizarin complexone, 1-(2-pyridylazo)-2-naphthol-2 (PAN), bromothymol blue, rhodamine 6G, pyrogallol red, morin, fuchsine, malachite green, bromothymol blue, pyrocatechol violet (PCV), chromazurol S, and aluminon are extracted with partition coefficients higher than 100. A possibility of the extraction-photometric determination of gallium with PCV and cobalt with PAN is shown. The proposed procedures do not require the use of fire-hazardous, volatile, and toxic organic solvents. Keywords: gel extraction with surfactants, photometric reagents, potassium bis(alkylpolyoxyethylene)phosphate (oxyphos B) DOI: 10.1134/S1061934818030048, Extraction systems with aqueous and organic phases, which segregate because of the limited mutual solubility of water and the organic solvent, have become most widespread. These systems, along with advantages, [...]

Abstract: X-ray absorption near edge structure (XANES) spectroscopy was used to study a freshly prepared reference daguerreotype surface as the first step in devising improved methods for the conservation of [...]

Abiotic and biotic components of a serpentine Mediterranean soil were studied in terms of heavy metal and nutrient concentrations, microbial biomass, and structural and functional characteristics of the soil nematode community. We explored differentiations of the soil environment imposed by vegetation, sampling the bare soil and soil under Buxus sempervirens, Juniperus oxycedrus, Cistus creticus and Thymus sibthorpii. Organic matter, microbial biomass, nutrient availability and calcium/magnesium (Ca/Mg) ratio of the serpentine site were similar to those of degraded, non-serpentine Mediterranean ecosystems; the serpentine site showed potassium deficiency and high heavy metal load. Soil nematode abundance, especially of phytoparasites, was very low. Low enrichment and structure indices and high channel index values indicated a degraded, low-resource, stressful environment where fungal decomposition predominates. There was no differentiation of heavy metal concentrations among microsites. Bare soil exhibited high pH, low water content, low Ca/Mg (0.68), low nutrient concentrations, low abundance of most nematode groups, low values of maturity and plant parasitic indices, low nematode diversity and a distinct generic composition. Rhizosphere soil was differentiated according to the evergreen--sclerophyllous or seasonal-dimorphic habit of shrubs. This was reflected in soil nutrients and in all parameters of the soil nematode community. Additional keywords: Greece, heavy metals, maquis, nematode functional profile, phrygana, ultramafic soil., Introduction Serpentine soils are hostile to the growth of most plants. They are natural metalliferous environments, inheriting minerals from their parent ultramafic rocks. These rocks originate more directly from the [...]

This study describes the applicability of lignocellulosic fiber dispersed in ethylene vinyl acetate (EVA) to adsorb Pb(li), Cr(lll), and Cr(VI) ions in aqueous solutions. Water absorption studies revealed that metal-ion uptake does not only take place on the surface of the adsorbent but ions can also diffuse into the composite. The adsorption of the metal ions under different experimental conditions was studied. Solute concentration, pH, and contact time were used to assess the adsorption capacity and efficiency. The amount of metal adsorbed increased to 7 mg/g with an increase in solute concentration but compromising the efficiency. Adsorption equilibrium was reached after 3 h, when the maximum lead adsorption was above 80%. The optimum pH for the adsorption of Pb(ll) and Cr(lll) was 6.5, and pH 2.5 was used for the adsorption of Cr(VI). Competitive adsorption revealed the order of adsorption to be: Pb(tl) > Cr(VI) > Cr(lll). POLYM. ENG. SCI., 52:760-767, 2012. ©2011 Society of Plastics Engineers, INTRODUCTION The presence of heavy metals like lead and hexavalent chromium in water poses a serious threat to human beings If the threshold amount in drinking water is exceeded. These [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2008.02.012 Byline: B. Sen Gupta (a), M. Curran (a), Shameem Hasan (b), T.K. Ghosh (b) Abstract: Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu.sup.2+ and Ni.sup.2+ from aqueous solutions on Irish peat moss was studied both as a pure ion and from their binary mixtures under both equilibrium and dynamic conditions in the concentration range of 5-100mg/L. The pH of the solutions containing either Cu.sup.2+ or Ni.sup.2+ was varied over a range of 2-8. The adsorption of Cu.sup.2+ and Ni.sup.+2 on peat was found to be pH dependent. The adsorption data could be fitted to a two-site Langmuir adsorption isotherm and the maximum adsorption capacity of peat was determined to be 17.6mg/g for Cu.sup.2+ and 14.5mg/g for Ni.sup.2+ at 298K when the initial concentration for both Cu.sup.2+ and Ni.sup.2+ was 100mg/L, and the pH of the solution was 4.0 and 4.5, respectively. Column studies were conducted to generate breakthrough data for both pure component and binary mixtures of copper and nickel. Desorption experiments showed that 2mM EDTA solution could be used to remove all of the adsorbed copper and nickel from the bed. Author Affiliation: (a) School of Chemical Engineering, Queen's University Belfast, BT9 5AG, UK (b) Nuclear Science and Engineering Institute, University of Missouri-Columbia, Columbia, MO 65212, USA Article History: Received 22 June 2006; Revised 21 December 2007; Accepted 29 February 2008

A dynamic 'two-site' model was formulated and tested for simulating the elution histories of copper ([Cu.sup.2+]) and lead ([Pb.sup.2+]) from a contaminated soil treated by poly(amidoamine) dendrimers. In the model, the metal sorption sites of the soil were divided into two compartments: one with a fast desorption rate and the other with a slow desorption rate. The model was tested for simulating and predicting [Cu.sup.2+] and [Pb.sup.2+] elution histories obtained from column experiments. Compared to the classical 'one-site' model and the modified 'gamma distribution' model, the 'two-site' model not only provides much improved power for simulating the observed metal elution data, but also can more accurately predict the metal elution histories under various experimental conditions including initial metal concentration in soil, dendrimer concentration, and pH. DOI: 10.1061/(ASCE)0733-9372(2008)134:4(238) CE Database subject headings: Abatement and removal; Models; Remedial action; Extraction procedures; Heavy metals; Soil pollution; Soil treatment.

Electrokinetic remediation technology is one of the developing technologies that offers great promise for the cleanup of soils contaminated with heavy metals. However, the performance of an electrokinetic remediation system depends on the interaction of a complex set of interrelated system variables and parameters. Many of these interactions were addressed in this study by incorporating geochemical reactions into electrokinetic remediation modeling. A one-dimensional transport model was developed to predict the transport and speciation of heavy metals (chromium, nickel, and cadmium) in soil during electrokinetic remediation as a function of time and space. The model incorporates: (1) pH-dependent adsorption of contaminants to the soil surface; (2) sensitivity of soil surface potential and electroosmotic flow to the pore water properties; and (3) synergistic effects of multiple chemical species on electrokinetic remediation. The model considers that: (1) Electrical potential in the soil is constant with time; (2) surface complexation reactions are applicable in the highly concentrated clay suspensions; (3) the effect of temperature is negligible; and (4) dissolution of soil constituents is negligible. The predicted pH profiles, electroosmotic flow, and transport of chromium, nickel, and cadmium in kaolin soil during electrokinetic remediation were found to reasonably agree with the bench-scale electrokinetic experimental results. The predicted contaminant speciation and distribution (aqueous, adsorbed, and precipitated) allow for an understanding of the transport processes and chemical reactions that control electrokinetic remediation. DOI: 10.1061/(ASCE)1090-0241(2008)134:1(91) CE Database subject headings: Electrokinetics; pH; Heavy metals; Kaolin; Adsorption; Remedial action.

Proton and metal ion binding to humic acids has been recognized as an important factor in controlling metal speciation and mobility in aqueous and soil environments. The binding and competition behavior of humics has not been fully described, however, due to the polydisperse mixtures of natural organic polyelectrolytes with different functional groups. The simplified discrete binding group type of model (Model A) was used in this study. Model A was applied to describe three single metals and their competitive binding on the humic acids. Model A considers only a single carboxyl group type and a single phenolic hydroxyl group type with a variable electrostatic interaction factor that is expressed as a polynomial equation. Metal binding experiments were performed using a batch-type dialysis equilibration method, and mass and charge balance expressions were used to calculate individual components of the system. The fit of Model A suggested that the major binding site for the three metal ions tested (Cd, Zn, and Cu) was a bidentate chelate of the carboxyl groups. Model A described two- and three-metal competition on the humic acids using the intrinsic stability constant for the single metal ion. The model used in this study adequately described the competition of two metals; however, it showed weaknesses when applied to more complex systems, especially when metals with substantially different binding characteristics were present. Model A presented a better prediction with adjusted Cu concentration (2:1:1 Cu/Cd/Zn). Abbreviations: HA, humic acid.

Abstract: The treatment of hazardous wastes using cement-based solidification-stabilization (S-S) is of increasing importance as an option for remediating contaminated sites. Indeed, among the various treatment techniques, S-S is one [...]

Microcosms are used to segregate the effects of two heavy metals (Pb and Cr) and also explore the impact of aromatic hydrocarbons on microbial community structure and function. One of the two energy substrates (glucose or xylene) is added to provide the necessary force for selection to operate and drive changes in community composition.

A conceptually new approach for generating a strong fluorescence signal through chemical bond formation mediated by a heavy-atom removal process is described. The method is found to have constructive photophysical properties such as exceptional quantum yield and very low limits of fluorogenic DNA detection.

Byline: Valentin Nenov, Bogdan Bonev Satisfactory sorption capacity towards heavy metals of several physically modified chelating resins at low pH is reported. It was found that the linear sorption isotherms are the most appropriate for describing the sorption of Ni and Pb. The data obtained revealed that the chelating resins studied are able to remove selectively copper from a complex synthetic solution containing Fe, Mn and Pb. The regeneration of Lewatit TP 208 by 10% H2SO4 in batch conditions proved to be effective through three consecutive runs of loading-regeneration.

Byline: Jose Aguado, Jesus M. Arsuaga, Amaya Arencibia Propylthiol-functionalised mesoporous silica SBA-15 prepared by co-condensation has been tested for heavy metal removal. Adsorption from aqueous solution was examined for Cu(II), Pb(II), Cd(II), and Hg(II). Adsorption isotherms were determined at 20[degrees]C and Langmuir and Freundlich models were fitted to experimental data. The results from adsorption experiments indicate that mercury is efficiently removed from water. Copper, lead and cadmium uptakes from aqueous solution are noticeable but significantly smaller than mercury removal; moreover, lead and cadmium adsorption isotherms exhibit no adsorption maximum within the investigated range of concentration. The influence of solution pH on lead adsorption was also investigated.

Byline: M.V. Galperin, M.A. Sofiev An improved MSC-East model for the evaluation of the atmospheric concentration and deposition of heavy metals in Europe and adjoining regions is described. At present, modelling of lead, zinc, arsenic, cadmium and mercury concentrations is carried out within the EMEP grid. At the same time, MSC East performs model calculations within the whole northern hemisphere to the north of 20[degrees]N. Each cell of 150 x 150 km is simultaneously an emitter and receiver. Input data contain meteoinformation and emission data but not measurements. Emissions in a grid cell, with an indication of the country (region) of a specific source, and information on its temporal irregularity are also used. A Eulerian model with total splitting of all processes is used. Its main feature is variable Eulerian time and spatial steps. The steps are chosen so that artificial viscosity is equal to zero and advection velocity is kept constant. An approximation with three reference points is used for the vertical concentration distribution. It is assumed that the position of the boundary layer, the vertical diffusion rate and the dry deposition rate depend on the temperature and the underlying surface state. Exchange with the troposphere and removal from the calculation area are taken into account, so that the balance between emission and deposition is kept. The size distribution of nested particles, chemical transformations and re-emission of mercury are considered. The results of transboundary transport calculations for Europe in 1989-1991 are presented, as are evaluation data on the pollution of the Arctic and Asia from European sources.

Byline: T. R. Muraleedharan, L. lyengar, C. Venkobachar Among the various technologies being suggested for heavy metal management, biosorption has emerged as the most promising. Though biosorbents have been used for most toxic metals, few reports on rare earths have appeared. This is primarily because rare earths are not traditionally considered as toxic, though they are. Secondly, rare earths are limited geographically, and only limited areas are affected by the pollution. This paper describes the application of an established biosorbent, Ganodenna lucidum, for biosorption of rare earths.

Byline: Jose Abrego Nitric acid leaching processes were evaluated for removal of heavy metals from samples of residual sludge from an industrial and municipal wastewater plant. The study showed that an acid:water ratio of 1:1 and a nitric acid concentration of 2 mol 1−1 gave efficient removal of 86.7%, 100% and 100% of copper, nickel and arsenic.

Byline: Ligy Philip, Leela lyengar, C. Venkobachar The copper removal potential of Pseudomonas aeruginosa immobilised on different adsorbent resins has been studied. Duolite S-761 was found to be the most suitable matrix for bacterial immobilisation. Column studies were conducted using virgin as well as bacteria-immobilised resin. The experimental results reveal that resin with immobilised cells as sorbent increased the column capacity by more than 100%. Sorbed copper (II) could be desorbed using citrate buffer, and the bacteria immobilised reactor could be reused for removal of copper(II) with more than 90% efficiency. Further, the immobilised microbes were found to be viable. Hydrochloric acid (0.1 N) was able to desorb almost 100% of the sorbed metal, but the viability of the cells was affected, as expected.

Byline: M.A. Sofiev, A.M. Maslyaev, A.V. Gusev Special analytical methodology for model-model and model-measurement comparison is presented. It can be used with the data provided by airborne transport models. Basic statistical procedures have been elaborated for model calibration and for analysis of the quality and representativeness of the datasets. Special adaptation of well-known methods and elaboration of new ones have been carried out to take into consideration the specific features of the analysed data. Analytical procedures are applied in a software package developed as a user-friendly environment. It has been used for calibrations of models of the airborne transport of heavy metals and acid compounds and for inter-comparison of models of the dispersion of heavy metals.

Byline: J. Vite, C. Carreno, M. Vite We have previously patented a process for the extraction of toxic and valuable metals from foundry sands using a thermostatted column. In this paper, we describe a similar device for the removal of toxic metals from wastewater sludge. The wastes were finely ground and suspended in an aqueous pulp, and 10-40g of mineral acid or sodium hydroxide were added to reach a pH of 2, 5, 7 and 10, together with 4-10 g of a bisulphite and 0.3-1.5 g of sodium dodecyl sulfate. In some cases, this method can remove 100% of heavy metals from samples of various wastewater sludges. To study the removal efficiency of heavy metals, we used inductively coupled plasma atomic emission spectrometry (ICP-AES). The metallic alloys in the samples were studied by X-ray diffraction.

The various mechanisms involved in the characteristic spin-orbit induced [super 1]H([CH.sub.2]) chemical shifts that are induced upon the deprotonation of group 9 polyamine complexes are discussed. The heavier metal centers are shown to exhibit larger spin-orbit effects.

Byline: Visnja Orescanin, Ivanka Lovrencic Mikelic, Luka Mikelic, Mirta Rubcic, Stipe Lulic Degree of heavy metal pollution in soil caused by a former Ferromanganese Plant (FMP) and aluminium factory was investigated and the potential of metal mobility and bioavailability was estimated. Elemental concentrations in soil, vegetation and soil extracts were determined by EDXRF. In the nearest vicinity of the factory, soil concentrations ranged as follows: Mn 12,700-342,000 ppm, Zn 200-1090, Cu 50-440, Ni 60-330, V 60-410 and Pb 24-320 ppm. Significantly higher concentrations of V, Ni, Cu, Zn and Pb compared with control samples were also found in the soil samples taken in the vicinity of aluminium plant.

Byline: J. Han, P. Kanchanapiya, T. Sakano, T. Mikuni, M. Furuuchi, G. Wang The effect of the combustion atmosphere and the additives (CaO and HCl) on the behaviour of phosphorus and heavy metals during sewage sludge combustion was investigated. The results demonstrated that the reduction combustion promoted the vapourisation of phosphorus and heavy metals during sewage sludge combustion. Moreover, the concentrations of phosphorus and heavy metals in the bottom ash decreased with increasing HCl ratio, and the addition of CaO can stabilise heavy metals and phosphorus. It was also observed that phosphorus and heavy metals increased with increasing CaO ratio. Lastly, the difference of the TG-DTA curves with and without additives is discussed.

A metal-ion chelating amino acid ((8-hydroxyquinolin)-3-yl)alanine) is genetically encoded in Escherichia coli by an amber nonsense codon and corresponding orthogonal tRNA/aminoacyl-tRNA synthetase pair. The structure has showed a high occupancy of the heavy metal bound to the HQ-Ala residue and this method has facilitated the de novo design of metalloproteins with novel structures and functions, including fluorescence sensors.

The dynamics of metal speciation in several different monodisperse soft colloidal ligand suspensions characterized by a hard core and an ion-permeable shell layer is explained. The complex formation/dissociation rate constants of these suspensions are shown to highly vary because of the heterogeneity observed in the binding site distribution.