垃圾焚烧炉飞灰熔融特性及重金属的分布

对垃圾焚烧炉飞灰进行了差热分析及熔融实验,探讨了不同熔融温度对试样的灼烧减量及重金属分布特性的影响。结果表明,飞灰试样在1132℃时熔融,在1252℃～1290℃发生二次熔融。灼烧减量在1200℃达到最低值27.5％; Cr、Ni、Cu在熔融体中的固溶率随着沸点的升高而依次升高。重金属Pb、Cd、As、Hg挥发率均超过95％,挥发性依次为Pb>Cd>As>Hg;飞灰中Zn的氧化物熔融后转化为Zn2SiO4、ZnSiO3和ZnAl2O4等不易挥发的化合物,且Zn在1200℃时挥发率最低仅有66.7％。     

采用生命周期影响评价软件ReCiPe2016研究煤矸石和煤燃烧时As和Pb排放的环境效应

在煤和煤矸石燃烧的过程中，许多重金属污染物排放到大气中，从而造成严重的环境问题，因此研究煤燃烧过程中重金属排放的环境效应很有必要。本研究运用ReCiPe2016软件计算了煤矸石和煤在330 MW煤粉炉、50 kW循环流化床和实验室燃烧时As和Pb排放的环境影响值。结果表明当煤在330 MW煤粉炉燃烧的时候，底渣、飞灰、烟气中的As排放对环境的影响值分别是3.28×10^-6、2.68×10^-5、3.89×10^-3，底渣、飞灰、烟气中的Pb排放对环境的影响值分别是8.57×10^-6、6.00×10^-5、4.83×10^-2。底渣中的As和Pb排放对环境的影响比飞灰中低；As和Pb排放到大气对环境的影响比排放到土壤高。另外，当煤在50 kW循环流化床燃烧的时候，飞灰中的As和Pb排放对环境的影响值分别是3.26×10^-5和1.28×10^-4，底渣中的As和Pb排放对环境的影响值分别是1.16×10^-6和1.43×10^-5。本文的研究结果还表明当煤矸石在实验室燃烧的时候，随着燃烧温度的升高，As和Pb排放对环境的影响值升高。另外，As和Pb排放到大气对环境的影响占总环境的影响比例比排放到土壤高。此项研究还表明当煤在煤粉炉和循环流化床燃烧的时候，相同工况下Pb排放对环境的影响比As高。这项结果也为运用生命周期影响评价软件预测煤矸石在循环流化床燃烧As和Pb排放的环境影响提供基础数据。     

Micro-column preconcentration/separation using thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO2 as packing materials on-line coupled to inductively coupled plasma optical emission spectrometry for the determination of trace heavy metals in environmental water samples

A novel adsorbent of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO₂ was prepared and was used as a packing material for flow injection (FI) micro-column (20 mm × 4.0 mm i.d.) separation/preconcentration on-line coupled to inductively coupled plasma optical emission spectrometry (ICP-OES) simultaneous determination of trace metals (V, Cu, Pb, Cr) in environmental water samples. The experimental conditions for modified mesoporous TiO₂ packed micro-column separation/preconcentration of the target metals were optimized and the interference of commonly coexisting ions was examined. The adsorption capacities of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO₂ for V, Cu, Pb and Cr were found to be 14.0, 11.7, 17.7 and 14.5 mg g^− 1, respectively. The detection limits of the method were 0.09, 0.23, 0.50 and 0.15 µg L^− 1 for V, Cu, Pb and Cr, respectively, with a preconcentration factor of 20. The precision of this method were 1.7% (V), 3.9% (Cu), 4.6% (Pb) and 2.9% (Cr) (n = 7, C = 5 µg L^− 1), respectively. The developed method was applied to the determination of trace heavy metals in real samples and the recoveries for spiked samples were found to be in the range of 88.7-107.1%. For validation, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values.     

Interaction of SO2 with O2 over mixed Pt, Pd, Pt?Pd and Pt?Ru oxidation catalysts and combined treatment of automobile exhaust gases

TPD, XPS IR methods were used to study how the composition of mixed Pt and Pd contacts over Al₂O₃ affects the nature of SO₂ complexes formed in the presence of O₂. Two types of sulfates of different structure and binding strength are formed in SO₂ oxidation by oxygen over Pt and Pd contacts. Introducing elements such as Co and Cr into the composition, one can significantly reduce the formation of weakly binding sulfate-1 as well as sulfate-2 too.     

Combined Effects of Pulsed Discharge Removal of NO,SO2, and NH3 from Flue Gas

Experiments have been performed using pulsed high-voltage discharges with the aim of removing NO and SO ₂ from flue gas obtained from a methane burner. It is found that the NO conversion is strongly increased by the addition of SO ₂ or NH ₃ . When both gases are added simultaneously the increase almost disappears. The synergetic effect can be maintained, as is shown, when NH ₃ is introduced much later than SO ₂ . The SO ₂ removal is already 70% upon stoichiometric addition of NH ₃ , but the electric discharge improves this to >95% and reduces the NH ₃ leak to a few ppm. This increase is probably related to aerosol production by the pulsed discharge which enhances the ammonium salt production. A so-called history effect is observed, i.e., the removal of NO and SO ₂ depends on the time that is taken to reach the required energization. It appears that the discharge has to create favorable conditions for the cleaning process. Using the synergetic and history effects the best cleaning result, at initial concentrations of 300 ppm, is 80% NO removal and 95% SO ₂ removal with 3 ppm NH ₃ leak. In this case the energy cost is 13 eV/NO (or a yield of 90 g NO and 200 g SO ₂ per kWh). Possibilities for further improvement are indicated.     

PVT properties of concentrated aqueous electrolytes. II. Compressibilities and apparent molar compressibilities of aqueous NaCl,Na2SO4, MgCl2, and MgSO4 from dilute solution to saturation and from 0 to 50°C

The relative sound velocities (U-U°) of aqueous NaCl, Na₂SO₄, MgCl₂, and MgSO₄ solutions were measured from 0.05m to saturation and from 0 to 45°C. The sound speeds were combined with our earlier work and fitted to a function of molality and temperature to standard deviations within 0.3 m-sec^–1. The adiabatic compressibilities, _s, were determined from the sound speeds and used to calculate adiabatic apparent molar compressibilities, K_,s, isothermal compressibilities, , and apparent molar compressibilities, K, were determined from the adiabatic values using literature data for expansibilities and heat capacities. The values of K have been extrapolated to infinite dilution using an extended limiting law. The resulting K⁰ at various temperatures are in reasonable agreement with literature values. The results of this study have been combined with our earlier results to derive a secant bulk modulus equation of state for NaCl, Na₂SO₄, MgCl₂, and MgSO₄ solutions valid from 0 to 50°C and 0 to 1000 bar.     

Levels, risk assessment and sources of PM10 fraction heavy metals in four types dust from a coal-based city

The concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Hg and Pb in PM₁₀ fraction of four types of dust in a coal-based city, Fushun were detected by inductively coupled plasma-atomic emission spectroscopy. Results showed that most of the average concentrations for 11 metals in dust were higher than Chinese soil background values, especially for Cu, Zn, Hg, Cd and Pb with higher pollution index values. The re-suspended dust from residential and school building surfaces showed middle and high level of pollution by geoaccumulation index assessment which should raise attention as their potential health risk to local residenter and students. Six hotspots were found from spatial distribution analysis, locating at the northeast corner, central area close to mines, southwest area adjacent to an expressway, northeast area close to power plants, the city center and the industrial district reflecting the influence of agricultural activities, mining activities, vehicle emission, coal combustion and industrial activities. Correlation and principal component analysis showed accordant results indicating that vehicle emission, industrial activities, coal combustion and crustal materials were the main sources for heavy metals in PM₁₀ fraction of fugitive dust in Fushun.     

PVT properties of concentrated electrolytes. VI. The speed of sound and apparent molal compressibilities of NaCl,Na2SO4, MgCl2, and MgSO4 solutions from 0 to 100°C

The sound velocities of aqueous NaCl, Na₂SO₄, MgCl₂, and MgSO₄ solutions were measured from 25 to 95°C in 10^o intervals from dilute to saturated solutions. The results were combined with our earlier data and fitted to functions of molality and temperature to within ±0.4 m-sec^–1. The adiabatic compressibilities _S were calculated from sound speeds and used to calculate the adiabatic apparent molal compressibilities . Isothermal compressibilities and isothermal apparent molal compressibilities were calculated from _S using literature values for the expansibilities and heat capacities. The values of were extrapolated to infinite dilution using the Debye-Huckel limiting law to determine partial molal compressibilities. The apparent molal compressibilities were fitted to Pitzer's equations. The Pitzer parameters for the concentration dependence of were determined as a function of temperature. Correlations of and V at various temperatures were found for the electrolytes.     

Thermodynamic properties of transition metals in aqueous solution:4. The enthalpies of mixing aqueous solutions of CdCl2, CuCl2 and ZnCl2 with MgCl2 at varying ionic strength at 25°C

Enthalpies of mixing ΔH _m of aqueous solutions of CdCl₂, CuCl₂, and ZnCl₂ with MgCl₂ solutions were measured at ionic strengths of 1.0, 2.0, and 3.0 at 25°C. The excess enthalpy equations of Pitzer were then fitted to the resulting ΔH _m data. The resulting parameters are the temperature derivatives of the activity coefficient mixing parameters in the Pitzer system.     

Fabrication, characterization and magnetic behaviour of alumina-doped zinc ferrite nano-particles

Zinc ferrite nano-powders with a nominal composition of ZnFe₂O₄ were prepared by combustion synthesis using mixture of urea and ammonium nitrate as fuel. The influence of alumina-doping on the structural, morphological and magnetic properties of ZnFe₂O₄ nano-particles was investigated by means of X-ray powder diffraction (XRD), infrared (IR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and vibrating sample magnetometer (VSM). XRD and IR analyses confirm the cubic spinel phase of ZnFe₂O₄ nano-particles. The Zn ferrite presented a uniform microstructure with grain size in nano-scale. Alumina-doping brought about a change in the morphology of the as prepared ferrite from sphere-like to regular hexagon. Al₂O₃-treatment led to a decrease in the coercivity (H_c), magnetization (M_s) and magnetic moment (n_B) of the investigated system. The maximum decrease in the values of H_c, M_s and n_B due to the treatment with 1.5 wt% Al₂O₃ attained 13.5, 17.4 and 13.5%, respectively. The observed results can be explained on the basis of particle size and the Fe³⁺ concentration in the octahedral and tetrahedral sites involved in the cubic spinel structure.     

Adsorptive Removal of Cd,Cu, Ni and Mn from Environmental Samples Using Fe3O4-Zro2@APS Nanocomposite: Kinetic and Equilibrium Isotherm Studies

In this study, Fe₃O₄-ZrO₂ functionalized with 3-aminopropyltriethoxysilane (Fe₃O₄-ZrO₂@APS) nanocomposite was investigated as a nanoadsorbent for the removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions from aqueous solution and real samples in batch mode systems. The prepared magnetic nanomaterials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy/energy dispersion x-ray (SEM/EDX) Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Factors (such as adsorbent dose and sample pH) affecting the adsorption behavior of the removal process were studied using the response surface methodology. Under optimized condition, equilibrium data obtained were fitted into the Langmuir and Freundlich isotherms and the data fitted well with Langmuir isotherms. Langmuir adsorption capacities (mg/g) were found to be 113, 111, 128, and 123 mg/g for Cd, Cu, Ni and Mn, respectively. In addition, the adsorption kinetics was analyzed using five kinetic models, pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The adsorbent was successfully applied for removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions in wastewater samples.     

Thermodynamics of aqueous mixtures of sodium chloride,potassium chloride,sodium sulfate,and potassium sulfate at 25°C

Aqueous solutions of sodium chloride, potassium chloride, sodium sulfate, and potassium sulfate can be mixed in six ways to give ternary mixtures. Two of these have already been studied and results are now presented for the remaining four systems: H₂O–NaCl–K₂SO₄, H₂O–Na₂SO₄–K₂SO₄, H₂O–KCl–Na₂SO₄, and H₂O–KCl–K₂SO₄.     

Sorption of heavy metal from aqueous solution by volcanic ash

Lava ash from Mt. Etna volcano has been tested in a series of batch experiments in order to find out its suitability to act as metal ion sorbent from wastewaters. The results show that the removal of Cd, Cu and Cr elements reaches a suitable level. Various experimental parameters have been tried to verify their influence on the metal sorption. Each ionic species in solution can be removed only in its own range of optimal pH. No competitive effects have been found. The equilibrium data are satisfactorily fitted by the Freundlich isotherm. Desorption experiments by acid aqueous solutions result in leaching of negligible amounts of metal ions.     

Apparent molar heat capacity and relative enthalpy of aqueous NaOH between 323 and 523K

The apparent molar heat capacity, C _p,, of aqueous NaOH has been measured at temperatures between 50 and 250°C and molalities from 0.05 to 1.5 mol-kg^–1. Enthalpies of dilution L were also determined at 99°C and apparent molar relative enthalpies L were calculated up to 1.9 m. Measurements were performed by means of a flow calorimetric apparatus constructed in our laboratory and standardized for C _p, and L with aqueous Na₂SO₄ and with the formation of water from its ions, respectively. Characteristics and performance of this calorimeter are described in detail. Pitzer's semiempirical equations are used for the representation of the results and a general fitting of C _p, data is reported using also recent literature values measured between 4 and 55°C. The fitted parameters are finally utilized, through an integration procedure, to derive a general equation to calculate L at any temperature between 4 and 250°C.     

The Mixing Effect of Glycylglycine with KCl, KBr, and Na2SO4 from Volumetric and Viscometric Investigations at 298.15 K

The mixing effect of a simple peptide such as glycylglycine, in the presence of aqueous electrolytes, has been studied by examining their volumetric and viscometric behavior. The increase in the apparent molar properties of both glycylglycine and electrolytes is attributed to the interactions present among cation, anion, the head groups of the peptide, and the peptide bond. Simple equations are developed to account for such interactions with a view to correlate apparent molar properties of glycylglycine and electrolyte in their aqueous mixtures. Transfer properties of both glycylglycine and electrolyte are investigated in order to understand the changes in the property of one component by the addition of another. These interactions are also supported by viscosity data, for which a simple model is developed to correlate the variation in viscosities with composition of a component.     

Impact of rice crop residue burning on levels of SPM,SO2 and NO2 in the ambient air of Patiala (India)

Ground-based ambient air monitoring was conducted at five different locations in and around Patiala city (29°49′–30°47′N Latitude, 75°58′–76°54′E Longitude) in Northern India in order to determine the impact of open burning of rice (Oriza sativa) crop residues on concentration levels of suspended particulate matter (SPM), sulphur dioxide (SO₂) and nitrogen dioxide (NO₂). Covering sensitive, residential, agricultural, commercial and urban areas, sampling of these pollutants was organised during August 2006 to January 2007 and August 2007 to January 2008 casing two rice crop residue burning periods (October–November) using a high volume sampling technique combined with gaseous sampling systems. Gravimetric analysis was used in the estimation of total suspended particulate matter (TSPM) whereas SO₂ and NO₂ concentration was determined using spectrophotometer (Specord205, Analytikjena). Monthly average concentrations of SPM, SO₂ and NO₂ have shown significant up and down features at all the selected sampling sites during the study period. Monthly average concentrations (24 hour) of SPM, SO₂ and NO₂ varied from 100 ± 11 µg m^?3 to 547 ± 152 µg m^?3, 5 ± 4 µg m^?3 to 55 ± 34 µg m^?3 and 9 ± 5 µg m^?3 to 91 ± 39 µg m^?3. Substantially higher concentrations were recorded at the commercial area site as compared to the other sampling sites for all the targeted air pollutants. Levels of SPM, SO₂ and NO₂ showed clear increase during the burning months (October–November) incorporated with the effect of meteorological parameters especially wind direction, precipitation and atmospheric temperature.     

Two spectral QSPR models of porphyrin macromolecules for chelating heavy metals and different ligands released from industrial solvents: CH2Cl2, CHCl3 and toluene

ABSTRACT

Two simple and reliable correlations are introduced for the prediction of emission and absorption of porphyrins and their derivatives, i.e. metalloporphyrins and ligand coordinated metalloporphyrins. They can be used to sense the extracted precious metals. The proposed models require only simple structural parameters such as the number of carbon, metal and metal-free molecular fragments of desirable porphyrins or their derivatives. Since the proposed models depend on molecular structures of the desired compounds, they can be easily applied for complex molecular structures. Experimental data of 272 porphyrin derivatives were used to derive and test the novel models for the assessment of their emission (Em.) and absorption (Abs.) values in three solvents namely dichloromethane, toluene and chloroform. The values of the coefficients of determination (r ²) for the training set (183 compounds) in dichloromethane and three different test sets, corresponding to the three mentioned solvents, for the emission and absorption correlations were greater than 0.70. The calculated values of the root-mean-square error (RMSE) for the training sets of Em. and Abs. correlations were equal to 7.56 and 4.86 nm, respectively. Further statistical parameters also confirm the high reliability of the new models.     

Pilot-plant for NOx, SO2 and HC removal from flue-gas of municipal waste incinerator by electron beam irradiation

According to the basic research performed using a small size reactor at TRCRE of JAERI, the electron beam irradiation process was proved to be very effective for NO_x, SO₂ and HC removals from flue-gas of municipal waste incinerators. Based on this result, a pilot-plant was constructed for the demonstration of NO_x, SO₂ and HC removal performance using electron accelerator of maximum energy 0.95 MeV and maximum power 15kW.The pilot-plant was constructed at Matsudo City waste Disposal Center. The flue-gas of 1,000 Nm³/hr is guided from the waste incinerator flue-gas line of 30,000Nm³/hr to the pilot-plant to be processed by spraying Ca(OH)₂ slurry or powder and irradiation with high-energy electron beam of the accelerator. NO_x, SO₂ and HC are removed simultaneously from the flue-gas by the enhanced reaction with Ca (OH)₂ under irradiation.A brief explanation of the pilot-plant and preliminary results of the experiments are introduced in this paper.     

Denitrification and removal of heavy metals from waste water by immobilized microorganisms

Pseudomonas fluorescens, immobilized on soft polyvinyl chloride granules containing up to 35% softeners as carbon source, was used for simultaneous removal of nitrate and heavy metals. In typical continuous column operation, a 100 mg/L nitrate input solution was reduced to a 20 mg/L output at a feeding rate of 1500 mL/h, with a capacity of 14 kg/day/m³, and with an efficiency of 79%. In the same column, Pb(NO₃)₂ concentration was reduced from 1.0 to 0.05−0.1 mg/L and ZnSO₄ concentration was reduced from 10 to 5 mg/L.Pseudomonas aeruginosa immobilized on an O₂ plasma-treated melt blown polypropylene web was used for removing 95% of a 1.7 nCi PuCl₄ activity from a nuclear plant waste water in a batch operation.     

Polyphenols contents,heavy metals analysis and in vitro antibacterial activity of extracts from Cladanthus arabicus and Bubonium imbricatum of Moroccan Origin

Abstract

Aim of this study was to evaluate polyphenols and major and trace elements of Cladanthus arabicus and Bubonium imbricatum, along with their in vitro antibacterial activity against six multidrug resistant Enterobacteriaceae (Escherichia coli S33/16, E. coli S34/16, Proteus mirabilis S32/16, Klebsiella pneumoniae S12/16, Enterobacter cloacae S5/16, and Salmonella sp S12/14). UV spectrophotometry, ultra-high-performance liquid chromatography coupled to mass spectrometry and inductively coupled plasma mass spectrometry were used to evaluate total polyphenol content, quali-quantitative profile of single polyphenols and inorganic elements of the extract. The antibacterial activity was investigated by standard methods. Twelve polyphenols were identified in both plants and these were more concentrated in B. imbricatum than C. arabicus extracts. High levels of minerals, essential trace elements and tolerable levels of heavy metals (Cd, As and Pb) were found. Furthermore, the extracts showed also a strong in vitro antibacterial activity, particularly versus E. coli S33/16 (MIC, 0.125?mg ml^?1).