Properties of the waste treatment residual fly ash generated from municipal solid waste incinerator fly ash were investigated in this study. Six different mortar blends with the addition of the municipal solid waste incinerator fly ash were evaluated. The Portland cement replacement levels of the municipal solid waste incinerator fly ash used were 25%, 30% and 50%. Both, raw and washed municipal solid waste incinerator fly ash samples were examined. According to the mineralogical composition measurements, a 22.6% increase in the pozzolanic/hydraulic properties was observed for the washed municipal solid waste incinerator fly ash sample. The maximum replacement level of 25% for the washed municipal solid waste incinerator fly ash in mortar blends was established in order to preserve the compressive strength properties. Moreover, the leaching characteristics of the crushed mortar blend was analysed in order to examine the immobilisation of its hazardous contents.

• Klíčová slova
• Municipal solid waste incinerator fly ash, Portland cement, biotoxicity, compressive strength, leaching properties, mortar, pozzolanic/hydraulic properties,
• MeSH
• konstrukční materiály analýza   MeSH
• nakládání s odpady metody   MeSH
• popel uhelný analýza   MeSH
• spalování odpadů MeSH
• tuhý odpad analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• popel uhelný MeSH
• tuhý odpad MeSH

Heavy metals in fly ash from municipal solid waste incinerators are present in high concentrations. Therefore fly ash must be treated as a hazardous material. On the other hand, it may be a potential source of heavy metals. Zinc, lead, cadmium, and copper can be relatively easily removed during the thermal treatment of fly ash, e.g. in the form of chlorides. In return, wet extraction methods could provide promising results for these elements including chromium and nickel. The aim of this study was to investigate and compare thermal and hydrometallurgical treatment of municipal solid waste fly ash. Thermal treatment of fly ash was performed in a rotary reactor at temperatures between 950 and 1050°C and in a muffle oven at temperatures from 500 to 1200°C. The removal more than 90% was reached by easy volatile heavy metals such as cadmium and lead and also by copper, however at higher temperature in the muffle oven. The alkaline (sodium hydroxide) and acid (sulphuric acid) leaching of the fly ash was carried out while the influence of temperature, time, concentration, and liquid/solid ratio were investigated. The combination of alkaline-acidic leaching enhanced the removal of, namely, zinc, chromium and nickel.

• Klíčová slova
• Alkaline–acid leaching, Heavy metal, MSW fly ash, Removal, Thermal treatment,
• MeSH
• popel uhelný chemie   MeSH
• spalování odpadů MeSH
• těžké kovy izolace a purifikace   MeSH
• voda MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• popel uhelný MeSH
• těžké kovy MeSH
• voda MeSH

BACKGROUND, AIMS AND SCOPE: In the first part of this paper the main principles which control the dehalogenation of polychlorinated aromatic compounds on municipal waste incineration fly ash (MWI-FA) have been discussed and the model fly ash of similar dehalogenation activity has been proposed. Even if both systems show comparable dehalogenation properties, the main question concerning the postulated identical reaction mechanism in both cases is left unanswered. The other very important point is to what extent is this dechlorination mechanism thermodynamically controlled. The same problem is often discussed in the literature also for the de novo synthetic reactions. From the data it is clear that metallic copper plays a decisive role in the mechanism of the dehalogenation reaction. Although the results reported in the first part strongly support the idea that copper acts in this dechlorination as the reaction component, in contrast to its generally accepted catalytic behaviour, we believed that additional support for this conclusion can be obtained with the help of a thermodynamic interpretation of the mechanism of the reaction. RESULTS AND DISCUSSION: The pathways of hexachlorobenzene dechlorination on MWI-FA and model fly ash were studied in a closed system at 260-300 degrees C under nitrogen atmosphere. These pathways were the same for both systems, with the following prevailing sequences: hexachlorobenzene --> pentachlorobenzene --> 1,2,3,5-tetrachlorobenzene --> 1,3,5-trichlorobenzene --> 1,3-dichlorobenzene. Thermodynamic calculations were carried out by using the method of minimization total Gibbs energy of the whole system. In the calculations, the following reaction components were taken into account: all gaseous chlorinated benzenes, benzene, hydrogen chloride, a gaseous trimer Cu3Cl3, and also Cu2O and CuCl2 as solid components. The effect of the reaction temperature and the amount of copper and water vapour were considered as well. The effect of reaction temperature was determined from the data calculated for the 500 to 750 K temperature region. The effect of the initial composition was determined for the molar amounts of copper = 0.01-3 moles and water vapour = 0.2 to 3 moles per mole of chlorobenzene isomer CONCLUSIONS: The results of hexachlorobenzene dechlorination by MWI-FA and model fly ash under comparable reaction conditions allow us to conclude that both dechlorinations proceed via the same dechlorination pathways, which can be taken as an evidence of the identical dehalogenation mechanism for both systems. The relative percentual distribution of the dehalogenated products depends on the temperature, but not on the initial amount of water vapour or copper metal. On the other hand, the initial amount of copper substantially affects the conversion of the dehalogenation as well as the molar ratio of Cu3Cl3 to HCl in the equilibrium mixture. Comparison of the experimental with thermodynamic results supports the idea that dehalogenation reactions are thermodynamically controlled. RECOMMENDATIONS AND OUTLOOK: Thermodynamic analysis of the dehalogenation reactions may prove useful for a wide range of pollutants. The calculations concerning polychlorinated biphenyls and phenols are under study.

• MeSH
• chemické modely MeSH
• fungicidy průmyslové chemie   MeSH
• hexachlorbenzen chemie   MeSH
• kinetika MeSH
• měď chemie   MeSH
• odpadky - odstraňování metody   MeSH
• pevné částice MeSH
• popel uhelný MeSH
• průmyslový odpad MeSH
• spalování odpadů metody   MeSH
• teplota MeSH
• termodynamika * MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• fungicidy průmyslové MeSH
• hexachlorbenzen MeSH
• měď MeSH
• pevné částice MeSH
• popel uhelný MeSH
• průmyslový odpad MeSH
• uhlík MeSH

Soils in the vicinity of nonferrous metal smelters are often highly polluted by inorganic contaminants released from particulate emissions. We used a technique with double polyamide experimental bags (1-μm mesh) to study the in situ transformation of fly ash (FA) from a secondary Pb smelter in acidic soil profiles. Between 62 and 66% of the FA dissolved after one year's exposure in the soils, leading to complete dissolution of primary caracolite (Na(3)Pb(2)(SO(4))(3)Cl) and KPb(2)Cl(5), with formation of secondary anglesite (PbSO(4)), minor PbSO(3), and trace carbonates. Release of Pb was pH-dependent, whereas not for Cd and Zn. Significant amounts of metals (mainly Cd and Zn) partitioned into labile soil fractions. The field data agreed with laboratory pH-static leaching tests performed on FA, which was washed before the experiment to remove soluble salts. This indicates that appropriate laboratory leaching can accurately predict FA behavior in real-life scenarios (e.g., exposure in soil).

• MeSH
• hutnictví * MeSH
• kadmium analýza   MeSH
• koncentrace vodíkových iontů MeSH
• látky znečišťující půdu analýza   chemie   MeSH
• olovo chemie   MeSH
• popel uhelný analýza   chemie   MeSH
• půda * MeSH
• stromy MeSH
• zinek analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kadmium MeSH
• látky znečišťující půdu MeSH
• olovo MeSH
• popel uhelný MeSH
• půda * MeSH
• zinek MeSH

The management of an increasing amount of municipal waste via incineration has been gaining traction. Fly ash as a by-product of incineration of municipal solid waste is considered a hazardous waste due to the elevated content of various elements. The enrichment and distribution of 24 elements in fly ash from three wastes incinerators were evaluated. Two coarse (>100 μm and <100 μm) and five sub-sieve (12-16, 16-23, 23-34, 34-49, and 49-100 μm) particle size fractions separated on a cyclosizer system were analyzed. An enhancement in the enrichment factor was observed in all samples for the majority of elements in >100 μm range compared with <100 μm range. The enrichment factor of individual elements varied considerably within the samples as well as the sub-sieve particle size ranges. These variations were attributed primarily to: (i) the vaporization and condensation mechanisms, (ii) the different design of incineration plants, (iii) incineration properties, (iv) the type of material being incinerated, and (v) the affinity of elements.

• Klíčová slova
• Enrichment, Fly ash, Incineration, Particle size distribution, Wastes,
• MeSH
• popel uhelný chemie   MeSH
• spalování odpadů MeSH
• tuhý odpad analýza   MeSH
• velikost částic * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• popel uhelný MeSH
• tuhý odpad MeSH

The aim of this study was to evaluate whether unburned carbon particles present in fly ash can help in the retention of S, Cl, Br, As, Se, Cu, Ni, Zn, Ga, Ge, Rb, and Pb out of flue gas during the coal combustion at fluidised-bed power station where the coal was combusted along with limestone. The competitive influence of 10%-25% CaO in fly ashes on the distribution of studied elements was studied as well to be clear which factor governs behaviour of studied elements. Except of S (with significant association with CaO) and Rb and Pb (with major affinity to Al2O3) the statistically significant and positive correlation coefficients were calculated for the relations between unburned carbon content and Br (0.959), Cl (0.957), Cu (0.916), Se (0.898), Ni (0.866), As (0.861), Zn (0.742), Ge (0.717), and Ga (0.588) content. The results suggest that the unburned carbon is promising material in terms of flue gas cleaning even if contained in highly calcareous fly ashes.

• MeSH
• elektrárny MeSH
• látky znečišťující vzduch chemie   MeSH
• popel uhelný chemie   MeSH
• uhlí analýza   MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• látky znečišťující vzduch MeSH
• popel uhelný MeSH
• uhlí MeSH
• uhlík MeSH

This study evaluated lead and cadmium uptake by maize grown on soils artificially spiked with smelter fly ash and possible changes in chemical fractionation of these metals in the soil. Maize grown on the less contaminated soil (1,466 mg Pb kg(-1); 19 mg Cd kg(-1)) did not exhibit any chlorosis/necrosis symptoms or lower biomass yields compared to the control. The addition of the chelating agent ethylenediaminetetraacetic acid increased lead uptake by maize, as expected. Neither maize cultivation nor the addition of the chelant influenced significantly the chemical fractionation of lead and cadmium in the soil during the experiment.

• MeSH
• biomasa MeSH
• chemická frakcionace MeSH
• hutnictví MeSH
• kadmium analýza   metabolismus   MeSH
• kukuřice setá růst a vývoj   metabolismus   MeSH
• látky znečišťující životní prostředí analýza   metabolismus   MeSH
• olovo analýza   metabolismus   MeSH
• pevné částice analýza   chemie   MeSH
• popel uhelný MeSH
• půda MeSH
• uhlík analýza   chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kadmium MeSH
• látky znečišťující životní prostředí MeSH
• olovo MeSH
• pevné částice MeSH
• popel uhelný MeSH
• půda MeSH
• uhlík MeSH

Brown coal fly ashes were tested as potentially low-cost sorbents for the removal of synthetic dyes from waters. It was shown that both basic (cationic) as well as acid (anionic) dyes can be sorbed onto the fly ash. The adsorption can be described by the multi-site Langmuir isotherm. The sorption capacities were in the range of 10(-1)-10(-3)mmol/g and did not differ significantly for basic and acid dyes. The dye sorption decreased in the presence of organic solvents (methanol, acetone). The presence of oppositely charged surfactants exhibited a pronounced effect on the dye sorption-low concentrations of the surfactant enhanced sorption, whereas high concentrations solubilized the dyes and kept them in solution. Inorganic salts exhibited only a minor effect on the dye sorption. The sorption of basic dyes increased at high pH values, whereas the opposite was true for acid dyes.

• MeSH
• barvicí látky izolace a purifikace   MeSH
• čištění vody metody   MeSH
• koncentrace vodíkových iontů MeSH
• látky znečišťující vodu izolace a purifikace   MeSH
• pevné částice MeSH
• popel uhelný MeSH
• průmyslový odpad MeSH
• textilní průmysl MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• barvicí látky MeSH
• látky znečišťující vodu MeSH
• pevné částice MeSH
• popel uhelný MeSH
• průmyslový odpad MeSH
• uhlík MeSH

The waste low-calcium Czech brown coal fly ash represents a considerable environmental burden due to the quantities produced and the potentially high content of leachable heavy metals. The heterogeneous microstucture of the geopolymer M(n) [-(Si-O)(z)-Al-O](n).wH(2)O, that forms during the alkaline activation, was examined by means of microcalorimetry, XRD, TGA, DSC, MIP, FTIR, NMR MAS ((29)Si, (27)Al, (23)Na), ESEM, EDS, and EBSD. The leaching of heavy metals and the evolution of compressive strength were also monitored. The analysis of raw fly ash identified a number of different morphologies, unequal distribution of elements, Fe-rich rim, high internal porosity, and minor crystalline phases of mullite and quartz. Microcalorimetry revealed exothermic reactions with dependence on the activator alkalinity. The activation energy of the geopolymerization process was determined as 86.2kJ/mol. The X-ray diffraction analysis revealed no additional crystalline phases associated with geopolymer formation. Over several weeks, the (29)Si NMR spectrum testified a high degree of polymerization and Al penetration into the SiO(4) tetrahedra. The (23)Na NMR MAS spectrum hypothesized that sodium is bound in the form of Na(H(2)O)(n) rather than Na(+), thus causing efflorescence in a moisture-gradient environment. As and Cr(6+) are weakly bonded in the geopolymer matrix, while excellent immobilization of Zn(2+), Cu(2+), Cd(2+), and Cr(3+) are reported.

• MeSH
• alkálie chemie   MeSH
• difrakce rentgenového záření MeSH
• kalorimetrie metody   MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární struktura MeSH
• pevné částice * MeSH
• popel uhelný MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• uhlík * MeSH
• vápník analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alkálie MeSH
• pevné částice * MeSH
• popel uhelný MeSH
• uhlík * MeSH
• vápník MeSH

The leaching behaviour of fly ash (FA) from a secondary Pb smelter was assessed using the pH-static leaching experiment according to prEN 14997 (pH range 3-11) coupled with mineralogical investigation of the leached FA by XRD and Rietveld analyses and thermodynamic modelling using PHREEQC-2. The procedure was performed on fresh FA and FA washed at a cumulative L/S ratio of 60l/kg to remove readily soluble salts. For both fresh and washed FA, high amounts of inorganic contaminants were released under acidic conditions, exhibiting L-shaped leaching patterns: up to 300g Pb/kg, 4.5g Cd/kg, 4g Zn/kg, 1.05g As/kg and 70mg Sb/kg. The washing of soluble salts significantly decreased the leachability of Cd, Zn, As and Sb and increased the release of Pb, especially under acidic conditions. The leaching of fresh FA removed part of primary caracolite and all the KPb(2)Cl(5) and NaCl. The Pb release was controlled by the precipitation of anglesite and PbSO(3) under acidic conditions and of laurionite and carbonates (hydrocerussite and phosgenite) under alkaline conditions. In contrast, the washed FA was composed mainly of anglesite and PbSO(3), both phases being the main solubility-controlling phases for Pb over the whole studied pH range.

• MeSH
• dekontaminace metody   MeSH
• hutnictví MeSH
• koncentrace vodíkových iontů MeSH
• olovo izolace a purifikace   MeSH
• pevné částice chemie   MeSH
• popel uhelný MeSH
• průmyslový odpad * MeSH
• sulfidy MeSH
• termodynamika MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• lead sulfate MeSH Prohlížeč
• lead sulfide MeSH Prohlížeč
• olovo MeSH
• pevné částice MeSH
• popel uhelný MeSH
• průmyslový odpad * MeSH
• sulfidy MeSH
• uhlík MeSH