Study of traffic pollution by metals in Seville (Spain) by physical and chemical speciation methods

Eighty-three samples of atmospheric particles were collected at a representative traffic site in the Mediterranean city of Seville during a period of one year. Urban particles were collected on quartz filters with a high-volume sampler coupled with a cascade impactor which separates particles into six size ranges: >10, 10–4.9, 4.9–2.7, 2.7–1.3, 1.3–0.6, and <0.6 m. The total metal content, its distribution by size (physical speciation), and the concentrations of different chemical forms (chemical speciation) in particles less than 0.6 m were determined. The chemical speciation scheme furnished four fractions: soluble and exchangeable metals; carbonates, oxides, and reducible metals; oxidisable and sulfidic metals bound to organic matter; and residual metals. The samples were analysed by ICP–OES for Pb, Ni, Cd, S, Fe, Zn, Cu, Ba, Mn, and V. Gaseous pollutants, traffic intensities, and primary meteorological data provided by the atmospheric and traffic networks were statistically related to the analytical data. Analytical and statistical results from physical and chemical speciation singled out Ba as a valid tracer of vehicular traffic, instead of Pb, in cities with high traffic density. Another important relationship was found between Pb and Cu. Physical speciation of lead showed that the major risk for health was from fine particles less than 2.7 m, because particles between 2.7 and 0.6 m were the size fractions of the total suspended particles with the major mass abundance of lead (mainly particles between 2.7 and 1.3 m) and because particles less than 0.6 m were the fraction of airborne particles most abundant in the urban air. Chemical speciation results showed that special attention must be taken with Ni and Cd concentrations, because of their high potential bioavailability, mainly a result of the high solubility of the chemical forms of Ni in the finest particles.     

Adsorption of N-tallow 1,3-propanediamine-dioleate collector on albite and quartz minerals, and selective flotation of albite from greek stefania feldspar ore

The adsorption behavior of tallow 1,3-propanediamine-dioleate (Duomeen TDO) collector on albite and quartz minerals is assessed through Hallimond flotation, zeta potential, and diffuse reflectance FTIR investigations, together with the species distribution of the collector. The collector performance on albite separation from a natural feldspar material is evaluated in bench scale flotation tests. The Hallimond flotation responses of the minerals as a function of pH and collector concentration indicate that albite can be selectively floated from quartz at pH 2 where the doubly positively charged collector species adsorb on albite but not on quartz. However, the zeta potential and infrared spectra reveal that the adsorption behavior of the collector is similar on both minerals. The discrepancy in the flotation and adsorption results is attributed to the coarse and fine particle size fractions, and the shorter and longer equilibration periods employed in these studies respectively. The comparable adsorption on fine particles of albite and quartz at pH 2 is explained by the interaction of ammonium ions on silanol groups by hydrogen bonding as well as electrostatic interactions. The changes in zeta potentials are in good agreement with the formation of ionic species and free molecular forms of the collector. The IR spectra show the coexistence of neutral oleic acid together with charged amine species at low pH values in accordance with the species distribution diagram. Selective flotation of albite is accomplished from a natural feldspar material with tallow diamine-dioleate collector at pH 2 using sulfuric acid, only when the feed is deslimed prior to the bench scale flotation tests. An albite recovery exceeding 85% is achieved from a feed material containing about 50% albite.     

Combination of gravitational SPLITT fractionation and field-flow fractionation for size-sorting and characterization of sea sediment

A combination of gravitational split-flow thin (SPLITT) fractionation and sedimentation/steric field-flow fractionation (Sd/StFFF) has been used for continuous size-sorting of a sediment sample and for size analysis of the collected fractions. An IAEA (International Atomic Energy Agency) sediment material was separated into four size fractions (with theoretical size ranges <1.0, 1.0–3.0, 3.0–5.0, and >5.0 m in diameter) by means of a three-step gravitational SPLITT fractionation (GSF) for which the same GSF channel was used throughout. The GSF fractions were collected and examined by optical microscopy (OM) and by Sd/St FFF. The mean diameters of the GSF fractions measured by OM were within the size interval predicted by GSF theory, despite the theory assuming that all particles are spherical, which is not true for the sediment particles. The Sd/St FFF results showed that retention shifted toward shorter elution time (or larger size) than expected, probably because of the shape effect. The results from GSF, OM, and Sd/StFFF are discussed in detail.     

Chemical characterization of density separated submicrometer coal fly ash

A new geometrical particle size separation method in the range of submicrometer has been developed for coal fly ash. Coal fly ash particles prefractionated less than 5m in geometrical diameter were fractionated with a coupling of supersonical dispersion in methyl alcohol and filtration through antistatic Nucleopore filter into >1.0, 1.0–0.8, 0.8–0.6m.Submicrometer (1.0–0.6m) and micrometer coal fly ash (25–20m) were separated into six density fractions and their compositions measured by SEM-EDX were compared. For the both size fractions, for the low density fractions (<2.8 g/cm³) consisted mainly of aluminosilicates and the fractions of 2.8–3.2 g/cm³ consisted of oxides of aluminum, silicon and calcium, and in the fraction above 3.2 g/cm³ iron was rich. In submicrometer fly ash, phosphor and sulfur concentrated to the particles rich in calcium. In the heaviest fraction, the particles containing over 30 wt% titanium as oxide observed among the particles rich in iron. These fractions were revealed not as a single component, but as mixtures of several components.     

Characterization of heavy-metal-containing seepage water colloids by flow FFF, ultrafiltration, ELISA and AAS

Heavy-metal-containing humic colloids from seepage water samples of three different municipal waste disposal plants were characterized in terms of molecular weight, hydrodynamic radius and heavy metal content. The size distribution of the colloids was determined with ultrafiltration (UF) and flow field-flow fractionation (flow FFF). The humic colloids in the seepage water samples were characterized using an off-line coupling of flow FFF with an enzyme-linked immunosorbent assay (ELISA) for humic substances. The heavy metals in the different size fractions obtained by UF and flow FFF were determined using atomic absorption spectroscopy (AAS). The colloid size distributions obtained with UF showed a maximum of the distribution in the range 1–10 nm. Seepage water samples with high colloid concentrations had a second maximum in the range 0.1–1 m. The determination of colloid size with flow FFF gave different colloid size distributions for the three waste disposal seepage waters, whereas water from the oldest disposal plant showed the smallest colloid size with a maximum at 0.9 nm and water from the most recent plant showed the largest colloid size with a maximum at 1.3 nm. The determination of particle classes with regard to the chemical composition using a scanning electron microscope with energy dispersive X-ray fluorescence detector (SEM/EDX) showed that the particles can be divided into five classes: silicates, insoluble salts, iron(hydr)oxides, carbonates and organic colloids (humic colloids). Flow FFF/ELISA off-line coupling showed that the most frequently occurring colloids of the seepage waters were humic colloids and investigation of the UF-size-fractions with AAS showed that up to 77% of the total mass of a heavy metal element can be bound to particles, especially to humic colloids. Additionally, the distributions of the heavy metals Fe, Cu and Zn were investigated with flow FFF/AAS off-line coupling. These results also showed that a substantial amount of these heavy metals (up to 46%) was bound to humic colloids.     

Heterogeneous chemistry between PbSO4 and calcite microparticles using Raman microimaging

Currently, the smelting activities of lead and zinc are the loudest sources of local pollution by emission in the troposphere of dust of micrometer size containing PbSO₄. As the particles evolve in the troposphere, their chemical and physical properties – and hence their characteristics such as toxicity – change by accumulation of atmospheric heterogeneous reactions. Calcite (CaCO₃) represents a large part of the mineral fraction in tropospheric aerosols with aerodynamic diameters less than 10 μm. The calcite particles are expected to react with PbSO₄ particles. In an effort to model the chemical behaviour of PbSO₄ individual particles in the troposphere, we present the in situ Raman imaging results during the course of the reactions in a water droplet of PbSO₄ particles with a calcite microcrystal surface. The computer-microcontrolled XY scanning and Z focusing of confocal Raman imaging combined with multivariate curve resolution (MCR) of Raman images have resolved the severe spectral overlaps of the Raman spectra which are not resolved by the spatial resolution of the instrument (1 μm³). The results pointed out the identification and the mapping of Pb₃(CO₃)₂(OH)₂, PbCO₃ and CaSO₄·2H₂O (gypsum) on the calcite surface.     

Size fractionated impactor sampling of aerosol particles over the Atlantic Ocean from Europe to Antarctica as a methodology for source identification of Cd, Pb, Tl, Ni, Cr, and Fe

Four different samples of aerosol particles over the North Atlantic, South Atlantic, an area near the equator influenced by Saharan mineral dust, and the Antarctic Ocean were collected on board of the German research vessel Polarstern by a six stage cascade impactor system. A continental sample, typical in its size distribution pattern and heavy metal enrichment factors (relative to crust material) for industrialized areas, was used for comparison. To analyse the elements of interest, isotope dilution mass spectrometry (IDMS) using the thermal ionization technique was applied. The samples were digested with nitric acid followed by an electrodeposition of the heavy metals to be analysed in alkaline solution. Source identification could be carried out by the distribution of the heavy metals and enrichment factors on the different impactor stages using iron as a reference element for crustal origin. Two opposite types of size distribution patterns were obtained over the Atlantic Ocean. On the one hand, the main heavy metal fraction was found to be associated with the smallest particles collected on the last two impactor stages and the back-up filter with aerodynamic diameters (AD) of less than 0.95 m. This pattern together with the high enrichment factors of up to several thousand indicates combustion processes and biogenic emissions as possible sources and were typical for cadmium and lead. On the other hand, chromium and iron were preferably associated with the larger particles of >1.5 m AD. This and the low chromium enrichment factor demonstrate that the earth crust is the major source for these two elements in marine aerosol particles. Thallium and nickel could not be classified by one of these two size distribution patterns, which indicates that at least two different primary sources contribute to the content of these heavy metals in marine aerosol particles depending on the region investigated. Contrary to that, the sample collected over the Antarctic Ocean showed some significant differences. Here, a substantial amount of the total cadmium and lead was associated with the larger particles. However, relatively high enrichment factors found for cadmium, nickel, lead, and thallium in the smallest particles suggest a natural source, probably biogenic activities, in the Antarctic Ocean.Dedicated to Professor Dr. Dr. h.c. mult. J.F.K. Huber on the occasion of his 70th birthday     

CdS semiconductor nanoparticles in silica sonogel matrices

SiO₂ gels obtained by sonocatalytic method combined with DCCA were used as host-matrices for extremely fine dispersions of CdS semiconductor particles. Small crystallites were produced in situ by H₂S gas diffusion method. The particles were characterized by TEM and HRTEM, EXAFS, UV-Vis and Raman spectroscopies. The size of crystallites ranged from 5 to 10 nm. The optical transmission spectra showed the characteristic blue shift as a function of the particles size, as predicted by the theory. The optical and mechanical qualities of the samples were substantially improved by an infiltration method using a sono-sol which sealed the superficial pores thus ensuring greater longevity and the possibility of obtaining transparent gels by polishing.     

New method of producing mono-sized polymer gel particles using microchannel emulsification and UV irradiation

It has been established that the combination of microchannel (MC) emulsification and UV-induced gelation is quite effective in producing mono-sized gel particles from acryloyl-type monomer/polymer solutions. MC emulsification allows one to produce the monomer solution droplets with less than ca. 5% relative standard deviation. On the other hand, using UV-induced gelation technique, pre-gel droplets containing a photoinitiator gelate by irradiation of UV light for a few minutes without requiring heating and/or intermediate adding of reaction accelerator. Conveniently, the particle size is adjusted from a few m to ca. 100-m by changing the slit size of the MC plate. Furthermore, gel particles may contain a variety of materials, such as metals, pigments, dyes, oils, bubbles, or others, suggesting various potential industrial applications.     

Electron microscopy of submicron particles in natural waters—Morphology and elemental analysis of particles in fresh waters

Submicron particles larger than about 0.1m in pond and river waters were collected on a carbon film mounted on a specimen grid by centrifugation and then studied morphologically and analyzed for major elements heavier than sodium, with a high-resolution transmission electron microscope equipped with an energy dispersive X-ray analyzer. If available, the data were compared with those of particles artificially prepared under various conditions. Four typical particles—aluminosilicate, quartz, fine-particle aggregates containing silica and iron(III) oxide, and microorganisms—were found in fresh waters.     

Systematic Errors in the Determination of Trace Metals by GFAAS Technique,Part I

The behaviour of solutions containing 7 metals in trace range (pH=2) prepared in borosilicate glass and polyethylene containers and transferred into commercial polyethylene–polypropylene and home-made quartz autosampler cups for measurements were studied using graphite furnace atomic absorption spectrometry. The different interactions between metal solution and vessel material were observed for the metals studied. The most significant losses of chromium and nickel occurred on a polyethylene surface, while the highest absorbance signals were registered from quartz containers. Higher absorbance signals from quartz containers were also obtained for cadmium and copper solutions. Contrary to these results, the absorbance signals for lead solutions were lowest when measured from quartz vessels. The container material had no influence on the analytical signals of cobalt and manganese.Received January 15, 2003; accepted April 15, 2003 published online August 22, 2003     

Thermoluminescence analysis for testing the irradiation of spices

Thermoluminescence signals of irradiated and unirradiated spices and herbs are due to inorganic matter grains adhering to the surfaces. This study reports the mineral composition of this dust being, mainly quartz, calcite and philosilicates; it shows the differences between samples exposed and non-exposed to -radiation on the basis of TL signals after long storage periods (1–16 months). A saturation process in the TL signal is found when the samples absorb doses higher than 5 kGy. Finally, the TL glow curve intensities do not suffer significant changes with the dose rate of the -source used in the radiation process.     

The detachment of nylon particles from quartz plate by electro-osmotic flow

The direct application of electrokinetic phenomena to detergency was investigated. Experiments were carried out to remove particles from substrate by electro-osmosis. A model system which consisted of spherical nylon particles of 5m in mean diameter, a quartz plate, and wash liquid were used in analyzing the kinetic process of particle removal from substrate. When an electric field was applied to the system, electro-osmotic flow took place, and hence the particles were removed from the quartz surface. The -potentials of nylon particles and quartz plate were measured by electrophoresis. The rate constants of removal,, were obtained from the changes with time in the ratio of particle residue by applying the first-order reaction scheme. The value of increased with increasing electric field and with increasing concentration of surfactant. The total force of interaction between particle and plate was calculated on the basis of heterocoagulation theory of colloid stability.It was found from results thus obtained that the hydrodynamic force due to the electro-osmotic flow worked effectively as a mechanical force on the removal process and the adhesion force of particle to substrate reduced by adding surfactant.     

Small Diameter (3 μm), Large Pore (1500 Å) Octadecylsilica for Capillary Electrochromatography

An ODS packing material was specially designed for CEC to achieve high efficiency. The size of the particles was approximately 3.2 m based on scanning electron microscopy, and the average pore size of the particles was 1500 Å by mercury intrusion porosimetry measurement. The packing materials were used in sol-gel bonded continuous-bed columns. The performance of columns containing these 3 m, 1500 Å ODS particles was evaluated for CEC and compared to 3 m, 80 Å ODS particles. The electroosmotic velocity (EOF) for the 1500 Å ODS material was slightly greater than that for the 80 Å ODS material. An efficiency of 410,000 plates m^–1 was obtained for unretained thiourea with a 30 cm × 75 m i.d. 1500 Å ODS column, which was more than 2 times higher than the efficiency obtained from the 80 Å ODS column.Dedicated to Professor K. Jinno on the occasion of his 60th, birthday.     

Methodological Peculiarities of the Electron Probe X-Ray Microanalysis of Environmental Samples

A set of procedures was developed for the electron probe X-ray microanalysis (EPMA) of fish and animal bone tissues, solid snow sediments, and coal ashes. Various sample-preparation procedures and two variants of the optimum conditions for analytical measurements were considered. In calculating analyte concentrations, matrix effects were taken into account using ZAF methods and the function of generated X-ray distribution with depth, namely, by the PAP method and by adding a joint correction for absorption and atomic number within a biexponential (z) model. For EPMA of small fractions 1–5 m in size, an approach was proposed that takes into account the test sample size using an analytical expression. In calculations of concentrations for micron-sized particles, this approach can lower the relative deviation from the stoichiometric composition from 36.8% to 22.2%. In developing the procedures, the potentialities of the proposed technique were assessed and its metrological characteristics were determined.     

UV-Induced Formation of [Fe(bpy)3]2+ Complex and its Confinement into Silica Fine Particles

Silica fine particles in a single or sub-micrometer regime, containing FeCl₃ and 2,2-bipyridine (bpy), were prepared by utilizing reverse micellar method. Formation of tris-bpy iron(II) ([Fe(bpy)₃]²⁺) complex was induced in the silica fine particles by UV irradiation at 365 nm. The starting micellar solution was obtained by an injection of 0.04 cm³ HCl aqueous solution into 5 cm³ tetraethyl orthosilicate (TEOS)/cyclohexane (2 cm³/3 cm³) mixed solution containing 4–14 vol% of nonionic surfactant, polyoxyethylene(5) nonylphenyl ether (NP-5). Size of the silica particles was regulated by the concentration of NP-5.     

Trace elements in municipal solid waste incinerator fly ash

Municipal solid waste incineration (MSWI) significantly reduces volume and mass by as much as 80%, prolonging the life span of landfills. The concentration of heavy metals in the ash and their ability to leach into ground water is a serious concern when siting and designing MSWI ash landfills. Improved technology captures most heavy metals in the ash. The distribution of elements among the different ash particle sizes was determined by NAA. The bottom ash residue was separated into fractions ranging from 9.5 mm to 0.3 mm. The fly ash was separated into fractions from 250 m to 20 m. Landfills usually bury a mixture of both. The combined ash was separated into fractions over the entire range from >9.5 mm to <20 m. Thermal and epithermal neutron irradiations of size fractionated MSW bottom, fly and combined ash were performed to determine the distribution of various metals within the ash. Compared to normal soil, the ashes contained elevated amounts of numerous elements. Concentrations of the more enriched elements (Ag, Cd, Cr, Cu, Hg, Sb, Se, Sr and Zn) in fly ash were of particular interest as source markers.     

Preparation of highly concentrated nanostructured dispersions of controlled size

This article presents the use of a shearing procedure for the preparation of stable nanostructured dispersions of lipid mesophases. This new application of the shearing technique is compared with the well-established ultrasonication method for the emulsification of these mesophases in water in terms of particle size, particle size distribution and available concentration range. With a laboratory-built shear device based on a Couette cell, it was possible to produce high quantities of internally self-assembled emulsion particles of controlled size at concentrated hydrophobic phase contents (_o) of up to 70 wt%. The concentration limit of 70 wt% could be reached however, the maximum attainable concentration depended on the internal structure type of the particles. The limit was thus easily attained for emulsified microemulsions (EME) as well as for the emulsified inverse hexagonal phase (H₂), whereas it was found to be lower for emulsified discontinuous (Fd3m) and bicontinuous (Pn3m) cubic phases. Moreover, by shearing, it was possible to keep the size of the particles relatively constant when increasing _o, whereas the particle size significantly increased with _o when ultrasonication was employed. By means of ultrasonication, the hydrodynamic radius of the particles could be tuned linearly between 85 to 180 nm as a function of _o up to a maximum of 20 to 30 wt%. Below the maximum concentration limit, particles displayed a well-controlled size.     

Synthesis, characterization and potential biomedical applications of N-succinimidyl ester functionalized, polypyrrole-coated polystyrene latex particles

N-Succinimidyl ester functionalized polypyrrole-coated polystyrene latex particles (PS_E-PPyNSE) were prepared by the in situ copolymerization of pyrrole and the active ester-functionalized pyrrole (pyrrole-NSE) in the presence of polystyrene latex particles. Polystyrene microspheres were prepared by emulsion polymerization (PS_E) leading to particles having a diameter of 450 nm. These PS_E particles were precoated with poly(N-vinylpyrrolidone) prior to the in situ copolymerization of pyrrole and pyrrole-NSE. The initial comonomer concentration fractions were 25/75, 50/50 and 75/25 for pyrrole and pyrrole-NSE, respectively. The PPy-coated PS_E particles were characterized in terms of morphology, particle size, electrophoretic mobility and chemical composition. The study of morphology by means of scanning electron microscopy showed roughening of the underlying PS_E particles owing to the addition of PPyNSE, the overlayer thickness of which was estimated to be around 7 nm. Moreover, loading PPyNSE overlayers resulted in a shift of the electrophoretic mobility from –5.31 m cm/V s to a very small but positive value (0.082–0.112 m cm/V s). X-ray photoelectron spectroscopy and IR spectroscopy permitted the detection of pyrrole-NSE repeat units at the surface indicating that pyrrole and pyrrole-NSE did indeed copolymerize. The PS_E-PPyNSE particles were further evaluated as bioadsorbents of human serum albumin used as a test protein. For this study, PS_E-PPyNSE₅₀ particles, synthesized from a comonomer feed ratio of 50/50 in pyrrole/pyrrole-NSE, were used and were shown to attach efficiently human serum albumin macromolecules with a maximum amount of 0.2 mg m^–2.

Control of hollow size of micron-sized monodispersed polymer particles having a hollow structure

Micron-sized monodispersed cross-linked polymer particles having one hollow in the inside were produced by seeded polymerization for the dispersion of (toluene/divinylbenzene)-swollen PS particles prepared utilizing the dynamic swelling method which the authors proposed. In order to control the hollow size, the weight ratio of toluene/PS was changed in the range of 520. The hollow size increased with an increase in the weight ratio. Even if benzene and xylene were used in place of toluene, similar hollow particles were produced, though the hollow size was affected by their solubility in water.Part CLIII of the series Studies on Suspension and Emulsion