ZINC SPECIATION IN POWER PLANT BURNING MIXTURES OF COAL AND TIRES

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Zinc speciation in power plant burning mixtures of coal and tires Luis F.O. Silva1, Marcos L.S. Oliveira2, Carmen Serra3, James C. Hower4,* 1

2

3 4

Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development – IPADHC, Capivari de Baixo, Santa Catarina, Brazil. [email protected] Development Department of Touristic Opportunities, Catarinense Institute of Environmental Research and Human Development – IPADHC, Capivari de Baixo, Santa Catarina, Brazil Servicio de Nanotecnologıá y Ana´lisis de Superficies C.A.C.T.I., Universidade de Vigo, Vigo, Spain University of Kentucky Center for Applied Energy Research, Lexington, KY, 40511, USA. [email protected]

ABSTRACT Fly ash from the cyclone-boiler co-combustion of high-S, high volatile bituminous coal and tire-derived fuel (tdf) was studied using a variety of chemical, optical, and microbeam techniques. Fly ash, dominated by Al-Si glass with lesser amounts of coalderived carbons, Fe-spinels, and tire-derived carbons, has Zn concentrations ranging from 2200 ppm (1st ESP row) to 6900 ppm Zn (3rd ESP row). Zinc occurs in Zn-rich nanoparticles in the Al-Si glass phases and as ZnO in amorphous and crystalline nanominerals, Fe- and Zn-sulfides, Pb-Al-Fe sulfates, and Zn sulfates. Iron-rich, Al- and Ti-bearing spinels contain accessory Zn2+, Cr3+, Mn2+, and Pb2+. Fe-sulfates and phosphates nanoparticles incorporate As, Cr, V, Ni, and Zn. Fullerenes were not detected in this fly ash, potentially due to the higher temperature of combustion in the cyclone boiler. Zinc was detected by XPS, but the low binding energies mitigated against the determination of the speciation of the element. f 2011 The University of Kentucky Center for Applied Energy Research and the American Coal Ash Association All rights reserved.

ARTICLE

INFO

Article history: Received 03 May 2011; Received in revised form 05 July 2011; Accepted 14 July 2011 Keywords: zinc; tires; coal combustion; fly ash; fullerenes

1. Introduction Humans are increasingly exposed to anthropogenic ultrafine particles and nanominerals, increasing the urgency to explore toxicological impact and other adverse health effects arising from the exposure to ultrafine particles and nanominerals from coal power plants and spontaneous coal combustion (Hower et al., 2008; Silva et al., 2009; Silva and Da Boit, 2011). Our previous studies have concentrated on coal-combustion-derived particles, but there are a number of power plants burning mixtures of coal and non-coal fuels, such as petroleum coke and tires. Tire-derived fuel has attracted attention as a high-heating value replacement for small percentages of feed coal, typically 1–3% of the total feed,

* Corresponding author. Tel: 1-859-257-0261. Email: [email protected]

and as a means of averting disposal of a large percentage of waste tires (Hower et al., 2001, 2007; Hower and Robertson, 2004). In this study, the first on the detection and complex characterization of ultrafine/nano-particles assemblages in a power plant burning mixtures of coal and tires, we investigate the forms of nanocarbons, nanominerals, and others compounds containing hazardous trace elements (in particular Zn) in fly ashes (FA) from the combustion of high-S coal and tire-derived fuel, the latter about 2–3% of the total fuel feed, in a 100-MW cyclone utility boiler. 2. Methods Coal and FA were sampled at a western Kentucky power plant in the course of the pentannual sampling of Kentucky power plants by the University of Kentucky Center for Applied Energy Research (CAER) (Hower et al., 2009). The coarse coal + tire-derived fuel feed

doi: 10.4177/CCGP-D-11-00008.1 f 2011 The University of Kentucky Center for Applied Energy Research and the American Coal Ash Association. All rights reserved.

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Silva et al. / Coal Combustion and Gasification Products 3 (2011)

Fig. 1. A/ Anisotropic coke (a) showing interference colors, with included inertinite (i). B/ Anisotropic coke (a) with pyrrhotite (s) in lumens. C/ Carbon from tire-derived fuel (tdf). D/ Carbon from tire-derived fuel (tdf), some of it showing development of anisotropic (a) domains.

was sampled at two feed hoppers. The FA was sampled in one hopper for each of the three electrostatic-precipitator (ESP) rows. Fly ash petrology was analyzed on Sudan Black-laced epoxybound pellets prepared to a final 0.5-mm polish with 503 oilimmersion optics and polarized white light following procedures initially defined by Hower et al. (1995) and refined and expanded since that publication. Basic FA chemistry was conducted following ASTM procedures. Major and minor elements were determined by X-ray fluorescence at the CAER following procedures outlined by Hower and Bland (1989) and by a variety of methods at the US Geological Survey’s Denver Laboratories following procedures after Meier et al. (1996). Mercury was analyzed at the CAER on a LECO AMA 254 Advanced Mercury Analyzer absorption spectrometer. Inductively coupled plasma mass spectrometry (ICP-MS, Xseries II), in a pulse counting mode (three points per peak), was used to determine most trace elements. Arsenic and Se were determined by ICP-MS using collision cell technology (CCT) in order to avoid disturbance of polyatomic ions. For ICP-MS analysis, samples were digested using an UltraClave Microwave High Pressure Reactor (Milestone). The basic load for the digestion tank was composed of

330-ml distilled H2O, 30-ml 30% H2O2, and 2-ml 98% H2SO4. Initial nitrogen pressure was set at 50 bars and the highest temperature was set at 240uC for 75 mins. The reagents for 50-mg sample digestion were 5-ml 65% HNO3, 2-ml 40% HF, and 1-ml 30% H2O2. The procedures of sample digestion and ICP-MS analysis were outlined by Dai et al. (2011). The major crystalline mineral composition of the FA samples was determined by means of a Siemens D5005 X-ray diffraction (XRD). The samples were ground by hand in a ceramic mortar and pestle, dry mounted in aluminum holders, and scanned at 8–60u 2h with Cu K-a radiation. Electron beam methods included Field Emission Scanning Electron Microscope (FE-SEM) with energy-dispersive X-ray spectrometer (EDS) capabilities and high-resolution transmission electron microscope (HR-TEM) with SAED (selected area electron diffraction) or MBD (microbeam diffraction), and scanning transmission electron microscopy (STEM). Time of flight secondary ion mass spectrometry (TOF-SIMS) was used to investigate the elemental and molecular structure of the samples. Surface composition for zinc speciation was determined by X-ray photoelectron spectroscopy (XPS). Details of

Silva et al. / Coal Combustion and Gasification Products 3 (2011) Table 1 Fly ash petrology. All units are in volume %. Trace 5 t sample no. ESP row glass mullite spinel quartz sulfide sulfate crystalline silicate lime rock fragment isotropic coke anisotropic coke inertinite pet coke tire-derived carbon unburned coal

93446 1 66.5 0.0 8.5 0.0 1.0 0.0 0.0 0.0 0.0 6.5 13.5 4.0 0.0 t 0.0

93447 2 88.5 0.0 3.5 0.0 0.0 0.0 0.0 0.0 0.0 1.5 5.5 1.0 0.0 0.0 0.0

93448 3 93.0 0.0 2.5 0.0 0.0 0.0 0.0 0.0 0.0 2.0 0.5 1.0 0.0 1.0 0.0

the microbeam procedures and nanominerals detection following sequential extraction have been published by Silva et al. (2011a, b, c). 3. Results and Discussion 3.1. Petrology The FA petrology is dominated by Al-Si glass, with secondary amounts of anisotropic coke with included inertinite (Figure 1a) and pyrrhotite (Figure 1b). Overall, the amount of glass increases from the first to the third ESP row as the amount of FA carbons decreases (Table 1). Isotropic coke and Fe-spinels are also among the fly ash constituents. Tire-derived fly ash carbons are present in trace to minor amounts (Figures 1c, d). 3.2. Chemistry The feed coal + tire-derived fuel (tdf) chemistry is presented on Table 2. The tires, however, being more difficult to grind than the coal, are not proportionately represented in the analysis. The FA chemistry is presented on Table 3. The contribution of the tires to the fly ash is reflected in the amount of Zn. As known from previous studies of both strictly coal- and coal + tdf – derived ashes, the concentration of volatile trace elements increases

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towards the back rows of the ESP array as a function of both the cooling of the flue gas and the decreased particle size, therefore, greater surface area, of the FA from the 1st to the 3rd row. This is well expressed in the increase of the Zn concentration from about 2200 to 6900 ppm. The tdf-derived fly ash carbon also increases in the same direction. Based on many observations of strictly coalderived FA, we know that Zn, As, and other elements tend to partition towards the back rows of ESP arrays (Mardon and Hower, 2004), therefore, we suspect that some of the Zn, both coal- and tdf-derived, enters the volatile phase in the boiler. Mineral nanoparticles (nanoscale versions of bulk minerals) and nanominerals (minerals or mineraloids that occur only in nanoscale forms (e.g., hematite and magnetite) are important major constituents in coal power plants (Chen et al., 2004; Hower et al., 2008; Silva et al., 2010a,b) and spontaneous coal combustion processes (Ribeiro et al., 2010; Silva et al., 2011c). In the present research, the incidental/anthropogenic Zn-nanopartices, Zn-ultrafine particles (e.g. Figure 2), and Zn-nanominerals (e.g. Figures 3– 5) detected collectively have immense surface areas relative to mm-sized and larger particles. The amount of Zn in the FA was relatively high (Table 3), and the Zn-rich nanoparticles and nanominerals occurred in complex aggregates in the non- and/or silicate minerals (Fe-, Si-, and Aloxides and phosphates) that preferentially embedded in the Al-Si (with lesser Ca, Fe, K, Mg, P) glass matrix (Figure 2). Glass phases are the main constituents of studied fly ash (Figure 2), entrapping several assorted crystalline ultrafine and nanomineral phases or melt clusters (spinels and metallic inclusions with Zn). The glasses have numerous discrete vesicles and fractures that resulted from rapid quenching in the transit from the boiler to the ESPs. The particles are spherical, highly aggregated, and can significantly affect the geochemical cycling of metals and the dissolution of redox-sensitive metal oxides, promoting potential environmental impacts. Generally, the studied CFA comprises spherical solids (Figures 2–5) and hollow cenospheres with sizes ranging from ,5 nm to .500 mm with a maximum of the particle size distribution in the 0.003- to 250-mm interval and have a heterogeneous chemical composition and different morphologies. While some particles are completely spherical, others have an elongate-elliptical morphology (Figure 2A). The occurrence of elongate-elliptical Al-Si ash particles indicates that the residence time in the high temperature zone of the furnace was too short for complete sphere formation/

Table 2 Feed coal chemistry. Proximate, ultimate, and S forms on a weith % basis. Minor elements on ppm ash basis; with exception of Se, Hg, and Cl on ppm whole coal basis sample

Ash

Moisture

VM

FC

C

H

N

S

O

Spy

Ssulf

Sorg

HV (MJ/kg)

93443 93444

13.99 12.33

3.41 3.82

36.9 37.61

45.7 46.24

63.77 65.9

4.69 4.93

1.41 1.44

4.85 3.95

11.29 11.45

2.76 2.05

0.11 0.07

1.98 1.83

26.81 27.31

sample

SiO2

Al2O3

Fe2O3

CaO

MgO

Na2O

K2O

P2O5

TiO2

SO3

93443 93444

37.13 40.4

14.93 16.5

25.68 22.44

8.53 8.38

0.73 0.77

0.53 0.58

1.87 1.99

0.11 0.09

0.76 0.87

12 11.22

sample

V

Cr

Mn

Co

Ni

Cu

Zn

As

Rb

Sr

Zr

Mo

Cd

Sb

Ba

Pb

93443 93444

159 186

95 93

443 365

65 58

36 50

dl dl

53 57

87 78

dl 1

dl dl

186 175

dl dl

1 1

11 10

262 305

23 25

sample

Se

Hg

Cl

93443 93444

1.4 1.38

0.3 0.24

9 29

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Table 3 Fly ash chemistry. Samples 93446, 93447, and 93448 correspond to the first, second, and third electrostatic precipitator (ESP) rows, respectively. The first through third row path also corresponds to the decrease in flue gas temperature. Ultimate analysis on a weith % basis. Minor elements on ppm ash basis; with exception of Se and Hg on ppm whole ash basis. sample

Ash

Moisture

C

H

N

S

O

93446 93447 93448

81.27 85.77 89.39

0.4 0.77 0.88

12.59 7.22 4.3

0.12 0.3 0.24

0.17 0.13 ,0.01

1.24 1.64 1.95

4.61 4.94 4.12

sample

SiO2

Al2O3

Fe2O3

CaO

MgO

Na2O

K2O

P2O5

TiO2

SO3

93446 93447 93448

42.28 39.36 38.32

17.59 16.65 16.07

26.8 28.63 28.73

5.15 4.6 4.37

0.86 0.87 0.87

0.87 1.09 1.18

3.25 3.37 3.43

0.17 0.23 0.25

1.15 1.25 1.3

1.59 2.01 2.72

sample

V

Cr

Mn

Co

Ni

Cu

Zn

As

Rb

Sr

Zr

Mo

Cd

Sb

Ba

Pb

93446 93447 93448

310 383 412

133 165 174

375 394 402

74 82 83

96 119 141

135 224 137

1370 3520 6579

183 301 323

dl dl dl

dl dl dl

176 181 176

3 3 14

1 1 1

11 12 11

406 461 484

54 85 91

sample

Se

Hg

93446 93447 93448

16.12 30.44 46.58

0.16 0.49 0.59

Fig. 2. FE-SEM general illustration. (A) Completely spherical particles and resemble an elongate-elliptical morphology; (B and D) Cenospheres; (C) Complex association between amorphous Al-Si-minerals, mullite, Fe-oxides and Zn-sulfates particles.


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Fig. 3. (A) crystaline zinc oxide contain amorphous carbonaceous particles. (B) nanowires growing from a thin platelet base and parallel to each other to form a bundle; (C) General ZnO agglomerate.

generation (Goodarzi and Sanei, 2009) and/or gas flow was turbulent, also quite likely. In addition, Zn was detected as ZnO (Figure 3), imbedded in amorphous and/or crystalline Fe nanominerals (Figure 4); with sulfides (e.g. sphalerite, Figure 5); in Pb-Al-Fe-sulfates, some in association with glass (e.g. anglesite [PbSO4]); and with pure complex sulfates in minor abundance (gunningite [ZnSO4 N H2O]; zinkosite [ZnSO4]; bianchite, ZnSO4 N 6H2O; and goslarite, ZnSO4 N 7H2O). For these hydrated Zn-nanosulfates, the composition may change during sample processing or in the HR-TEM vacuum. However, these minerals (after solubilised by water and before crystallized) were easily identified by FE-SEM/EDS/SAED study after water extraction. These results were interesting for under-

stand of Zn-sulfates leaching in the environmental during FA deposition. Massive ZnO with different morphologies (Figure 3) was detected by HR-TEM/EDS/SAED. ZnO nanominerals have received broad attention due to their value in electronics, antibacterial agents, optics, in pigments, in sun screens, in photonics, and in polymers or tires as stabilizers (Liu et al., 2009). Of course, the latter use is one of the vectors for Zn incorporation into the fuel blend and, subsequently, the FA under investigation. Despite the excellent advantages, the ecological risk arising from their release during the production and application process has received increasing attention in many reports. Nano-ZnO has been found to be toxic to algae (Aruoja et al., 2009; Wong et al., 2010),

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Fig. 4. Zn-bearing Fe-nanominerals detected by EDS (white zones). (A) Goethite; (B) Hematite; (C) Magnetite; (D) Jarosite pseudomorph after pyrite.

crustaceans (Blinova et al., 2010), fish (Wong et al., 2010), bacteria (Zhang et al., 2010), nematodes (Wang et al., 2009), plants (Lin et al., 2008) under aquatic and aerosol exposure modes (Wu et al., 2010) at various levels. Deleterious human health effects resulting in pulmonary changes from inhaled ZnO have only been documented in connection with acute high or long-term occupational exposure at coal power plants workers.

Fe-nanominerals with magnetite, hematite, goethite (Figure 4), as well as a series of Al-substituted and Ti-substituted varieties, are commonly identified in the studied FA. Varying amounts of Zn2+, Cr3+, Mn2+, and Pb2+ are incorporated into these spinels. Therefore, there is no single, uniform alteration path upon exposure to the environment. However, the composition of FA from different tdf- + coal-fueled plants are similar (Hower et al., 2001, 2007; Hower and


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Fig. 5. Sphalerite nanoparticles detected by HR-TEM/EDS/MB.

Robertson, 2004), which suggests that high-temperature processing of solid waste produces more-or-less uniform outcomes in view of both chemical and mineralogical characteristics. These findings are consistent with the fact that Zn2+, Cr3+, Mn2+, and Pb2+ have relatively high free energies (|DGfu|) of oxidization, indicating their easily oxidable properties (Wei et al., 2011). In the nanoparticulate hematite, surface Fe sites are also under coordinated relative to Fe in the bulk structure and may explain an increased sorptive capacity for aqueous Zn2+ relative to largersized hematite particles (Ha etal.,2009) and its potential leaching risk this FA. In addition, Fe-sulfates (e.g. jarosite, Figure 3D) and phosphate nanoparticles typically incorporate other elements such as As, Cr, V, Ni, and Zn. Based on the HR-TEM/EDS/MBD analyses, composite (Zn, Fe)3(PO4)2 could be present. The nanosphalerite grains (Figure 5) have been the focus of several structural studies. A pioneering study of nano-ZnS nanoparticles (Gilbert et al., 2004) reported the structure is stiffer than that of bulk ZnS, based on a higher Einstein vibration frequency in the nanoparticle (Brown and Calas, 2011). In the present study, the surface region of the detected ZnS nanoparticle

is highly strained. In a similar study of ZnS nanoparticles in contact with aqueous solutions containing various inorganic and organic ligands, stronger surface interactions with these ligands resulted in a thicker crystalline core and a thinner distorted outer shell (Zhang et al.,2010). The TOF-SIMS scan of the 550–900 mass/u range detected some heavy hydrocarbons, but none corresponding to fullerenes. This is contrast to the abundant fullerenes in the fly ash carbons from the stoker boiler combustion of a bituminous coal as reported by Silva et al. (2010a). The coal feed in the latter case is high volatile a bituminous, slightly high that the high volatile C bituminous rank of the coal burned at this plant. Rather than the coal rank, the difference in the nature of the ashes may be attributable to the combustion process, with the cyclone boiler used at the plant in this study operating at higher combustion temperatures than the stoker boiler, in excess of 1650uC (Kitto and Stultz, 2005, chapter 14) compared to about 1300 uC for a stoker boiler (Kitto and Stultz, 2005, chapter 16). The binding energy of selected elements is listed in Table 4 and the binding energies of Zn, based on the literature, are given on

Table 4 XPS binding energies and chemical state assignments Experimental / Binding energy B.E. (eV)/ Chemical state assignments

Samples ‘‘As received’’ 46

47

48

Carbon

Zinc

Iron

Silicon

Aluminum

Sulfur

C1s C1: 285/C-C,CH C2:286.52/C-O C3:288.87/ O5C-O C1: 285/C-C,CH C2:286.7/C-O C3:289.3/ O5C-O C1: 285/C-C,CH C2:286.76/C-O C3:289.05/ O5C-O

Zn2p3/2 1022.46 (Ni2+)

Fe2p3/2 710.8 (Fe3+) 712.58FeOOH 715.54 Fe2p Satellite 710.68 (Fe3+) 712.38FeOOH 715.03 Fe2p Satellite 710.83 (Fe3+) 712.48FeOOH 714.54 Fe2p Satellite

Si2p 103.44 Si 4+

Al2p 75.16 Al 3+

S2p3/2 163.78(5.7%) 169.26(94.4%)

103.5 Si4+

75.28 Al3+

164.4(4.6%) 169.24(95.4%)

103.48 Si4+

75.25 Al3+

169.29(100%)

1022.72 (Ni2+) 1021.51 1022.6(Ni2+)

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Table 5 Binding energy values from references (1 – Ba¨r et al., 2006; 2 – Chen et al., 2010; 3- Fiedler & Bendler, 1992; 4- Olivella et al., 2002; 5- Castanõ et al., 2007) Zn2p3/2

references S2p3/2 2+

1022.4 ZnO (Zn )

1

1021.7 ZnS (Zn2+)

1

1021.7 Zn metallic

2

,164 organic non oxidized (sulfur) ,168 sulfoxides S(O) 168 sulfone SO2 169.2 sulfonic acid SO3H 158.7–159.6 pyritic 161.2 162.5 sulfidic 163.7–164 thiophenes, thioethers, mercaptanes 166 sulfoxides 168 sulfone SO2 169.2 sulfonate 174.8–175.8 sulfates 167.4 eV sulfite ion (SO322) 169.2 eV sulfate ion (SO422)

references 3

4

5

Table 5. The Binding energy of Zn detected in the samples is between 1022.5–1022.7 eV, this value is mostly attributed to Ni2+ in the databases. However, the published binding energies for different Zn2p3/2 compounds, such as metallic Zn, ZnO, or ZnS are quite similar. To identify metallic Zn or ZnO by the Zn2p3/2 peak presents some difficulties. The chemical shifts of Auger peaks are usually more pronounced than photoelectron peaks, therefore, they can be used to identify the chemical states of elements as the complements to photoelectron peaks. However, in this study, due the low concentration of this element, the Auger peaks are not detected. The Zn signals are very low, close to detection limit of the XPS instrument and, therefore, the conditions are not optimal for determining the chemical state of these species. The third-row ESP sample does show stronger Zn signals than the first row ESP sample (Figure 6 and 7), but, at these low binding energies, it is not possible to draw conclusions about any relation between the flue gas temperature and the chemical state of the Zn. The sulfur detected in the samples is mainly (94%–100%) due to sulfate. 4. Conclusions Fly ash from the cyclone-boiler co-combustion of high-S high volatile bituminous and tire-derived fuel (tdf) was studied using a variety of chemical, optical, and microbeam techniques. The fly ash is dominated by an Al-Si glass with lesser amounts of coalderived carbons, Fe-spinels, and tire-derived carbons. Owing to the Zn in the tdf, the ESP fly ash contains from 2200 ppm (1st ESP row) to 6900 ppm Zn (3rd ESP row). As with other volatile trace elements, the increase in concentration of Zn from the 1st to 3rd ESP rows is a function both of the decrease in flue gas temperature and the decrease in particle size (therefore, greater surface area) in the same direction. Microbeam analysis showed that Zn-rich nanoparticles were associated with the Al-Si glass phases. Zinc also occurs as ZnO associated with amorphous and crystalline nanominerals, Fe- and Zn-sulfides, Pb-Al-Fe sulfates, and Zn sulfates. Iron-rich nanominerals, generally identified as spinels in the optical characterization, are present. Varieties with Al and Ti are present, and Zn2+, Cr3+, Mn2+, and Pb2+ are present as accessory elements in the spinels. Fe-sulfates and phosphates nanoparticles incorporate other elements such as As, Cr, V, Ni, and Zn.

Fig. 6. Comparison of Zinc XPS binding energy for fly ash sample 93446, the 1st-row ESP fly ash, and fly ash sample 93448, the 3rd-row ESP fly ash.

In contrast to the carbons from a stoker boiler studied by Silva et al. (2010a), fullerenes were not detected in this fly ash, potentially due to the higher temperature of combustion in the cyclone versus stoker boilers.


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Fig. 7. XPS Zinc Zn2p scans for fly ashes 93446, 93447, and 93448; the 1st-through 3rd –row ESP fly ashes, respectively.

Zinc was detected by XPS, but the low binding energies mitigated against the determination of the speciation of the element. Acknowledgements The work performed by the group from Brazil (FE-SEM, HRTEM, and XRD) was carried out with support from the Catarinense Institute of Environmental Research and Human Development – IPADHC. References Aruoja, V., Dubourguier, H. C., Kasemets, K., Kahru, A. 2009. Toxicity of nanoparticles of CuO, ZnO and TiO2 to microalgae Pseudokirchneriella subcapitata. Science of the Total Environment 407, 1461–1468. Ba¨r, M., Ennaoui, A., Klaer, J., Kropp, T., Saéz-Araoz, R., Allsop, N., Lauermann, I., Schock, H.-W., Lux-Steiner, M.C., 2006. Formation of a ZnS/Zn(S, O) bilayer buffer on CuInS2 thin film solar cell absorbers by chemical bath deposition. Journal of Applied Physics 99(12), art. no. 123503. Blinova, I., Ivask, A., Mortimer, M., Kahru, A., 2010. Ecotoxicity of nanoparticles of CuO and ZnO in natural water. Environmental Pollution 158, 41–47. Brown, G.E., Calas, G., 2011. Environmental mineralogy – Understanding element behavior in ecosystems, Comptes Rendus Geoscience doi:10.1016/ j.crte.2010.12.005

Castanõ, J.G., de la Fuente, D., Morcillo, M., 2007. A laboratory study of the effect of NO2 on the atmospheric corrosion of zinc. Atmospheric Environment 41, 8681–8696. Chen, S., Yan, F., Xue, F., Yang, L., Liu, J., 2010. X-ray photoelectron spectroscopy investigations of zinc-magnesium alloy coated steel. Materials Chemistry and Physics 124, 472–476. Chen, Y., Shah, N., Huggins, F.E., Huffman, G.P., 2004. Investigation of the microcharacteristics of PM2.5 in residual oil fly ash by analytical transmission electron microscopy. Environmental Science & Technology 38, 6553–6560. Dai, S., Wang, X., Zhou, Y., Hower, J.C., Li, D., Chen, W., Zhu, X., 2011. Chemical and mineralogical compositions of silicic, mafic, and alkali tonsteins in the late Permian coals from the Songzao Coalfield, Chongqing. Southwest China. Chemical Geology 282, 29–44. Fiedler, R., Bendler, D., 1992. ESCA investigations on schleenhain lignite lithotypes and the hydrogenation residues. Fuel 71, 381–388. Goodarzi, F., Sanei, H., 2009. Plerosphere and its role in reduction of emitted fine fly ash particles from pulverized coal-fired power plants. Fuel 88, 382– 386. Hower, J.C., Bland, A.E., 1989. Geochemistry of the Pond Creek Coal Bed, Eastern Kentucky Coalfield. International Journal of Coal Geology 11, 205–226. Hower, J.C., Graham, U.M., Dozier, A., Tseng, M.T., Khatri, R.A., 2008. Association of sites of heavy metals with nanoscale carbon in a Kentucky electrostatic precipitator fly ash. Environmental Science & Technology 42, 8471–8477. Hower, J.C., Rathbone, R.F., Graham, U.M., Groppo, J.G., Brooks, S.M., Robl, T.L., and Medina, S.S., 1995. Approaches to the petrographic characterization of fly ash. International Coal Testing Conference, 11th, Lexington KY, May 10– 12, 1995, p. 49–54.

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Hower, J.C., Robertson, J.D., Elswick, E.R., Roberts, J.M., Brandsteder, K., Trimble, A.S., and Mardon, S.M., 2007. Further Investigation of the Impact of the Cocombustion of Tire-derived Fuel and Petroleum Coke on the Petrology and Chemistry of Coal Combustion Products. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 29, 431–461. Hower, J.C., Robertson, J.D., Roberts, J.M., 2001. Combustion by-products from the co-combustion of coal, tire-derived fuel, and petroleum coke at a Western Kentucky cyclone-fired unit. Fuel Processing Technology 74, 125–142. Hower, J.C., Robertson, J.D., 2004. Chemistry and petrology of fly ash derived from the co-combustion of Western United States coal and tire-derived fuel. Fuel Processing Technology 85, 359–377. Hower, J.C., Robl, T.L., Thomas, G.A., Hopps, S.D., Grider, M., 2009. Chemistry of coal and coal combustion products from Kentucky power plants: Results from the 2007 sampling, with emphasis on selenium. Coal Combustion & Gasification Products 1, 50–62. http://www.coalcgp-journal.org/papers/ 2009/CCGP-D-09-00013-Hower-supp.pdf Kahru, A., Dubourguier, H. C., 2010. From ecotoxicology to nanoecotoxicology. Toxicology 269, 105–119. Kitto, J.B., Stultz, S.C., eds., 2005. Steam, 41st edition. Barberton, Ohio, Babcock & Wilcox Co. Lin, D. H., Xing, B.S., 2008. Root uptake and phytotoxicity of ZnO nanoparticles. Environmental Science & Technology 42, 5580–5585. Liu, Y., He, L., Mustapha, A., Li, H., Hu, Z. Q., Lin, M., 2009. Antibacterial activities of zinc oxide nanoparticles against Escherichia coli O157: H7. Journal of Applied Microbiology 107, 1193–1201. Mardon, S.M., Hower, J.C., 2004. Impact of coal properties on coal combustion by-product quality: Examples from a Kentucky power plant. International Journal of Coal Geology 59, 153–169. Meier, A.L., Lichte, F.E., Briggs, P.H., Bullock, J.L., 1996. Analysis of coal ash by inductively coupled plasma emission spectroscopy and inductively coupled plasma - mass spectroscopy. in Analytical methods manual for the Mineral Resource Surveys Program, US Geological Survey (ed. B.F. Arbogast). U.S. Geological Survey Open File 96-525, 109–125. Olivella, M. A., Palacios, J. M., Vairavamurthy, A., Del Rıó, J. C., De Las Heras, F.X.C., 2002. A study of sulfur functionalities in fossil fuels using destructive(ASTM and py-GC-MS) and non-destructive- (SEM-EDX, XANES and XPS) techniques. Fuel 81, 405–411. Ribeiro, J., Flores, D., Ward, C.R., Silva, L.F.O., 2010. Identification of nanominerals and nanoparticles in burning coal waste piles from Portugal. Science of the Total Environment 408, 6032–6041. Silva, L.F.O., Moreno, T., Querol, X., 2009. An introductory TEM study of Fenanominerals within coal fly ash. Science of the Total Environment 407, 4972–4974.

Silva, L.F.O., DaBoit K., Serra, C., Mardon, S.M., Hower, J.C., 2010a. Fullerenes and Metallofullerenes in Coal-Fired Stoker Fly Ash, Coal Combustion and Gasification Products 2, 66–79. Silva, L.F.O., Ward, C.R., Hower, J.C., Izquierdo, M., Waanders, F., Oliveira, M.L.O., Li, Z., Hatch, R.S., Querol, X., 2010b. Mineralogy and Leaching Characteristics of Coal Ash from a Major Brazilian Power Plant, Coal Combustion and Gasification Products, 2, 51–65. Silva, L.F.O., da Boit, K.M., 2011. Nanominerals and nanoparticles in feed coal and bottom ash: implications for human health effects. Environmental Monitoring and Assessment 174, 187–197. Silva, L.F.O., Querol, X., da Boit, K.M., Fdez-Ortiz de Vallejuelo, S., Madariaga, J.M., 2011a. Brazilian Coal Mining Residues and Sulphide Oxidation by Fenton s Reaction: an accelerated weathering procedure to evaluate possible environmental impact. Journal of Hazardous Materials 186, 516– 525. Silva, L.F.O, Izquierdo, M., Querol, X., Finkelman, R.B., Oliveira M.L.S., Wollenschlager, M., Towler, M., Pe´rez-Lo´pez, R., Macias, F., 2011b. Leaching of potential hazardous elements of Coal Cleaning Rejects. Environmental Monitoring and Assessment. Environmental Monitoring and Assessment, 175, 109–126. Silva, L.F.O., Oliveira, M.L.S., Neace, E.R., O’Keefe J.M.K., Henke, K.R., Hower J.C., 2011c. Nanominerals and ultrafine particles in sublimates from the Ruth Mullins coal fire, Perry County, Eastern Kentucky, USA. International Journal of Coal Geology 85, 237–245. Wang, H.H., Wick, R. L., Xing, B.S., 2009. Toxicity of nanoparticulate and bulk ZnO, Al2O3 and TiO2 to the nematode Caenorhabditis elegans. Environmental Pollution 157, 1171–1177. Wei, Y., Shimaoka, T., Saffarzadeh, A., Takahashi, F., 2011. Mineralogical characterization of municipal solid waste incineration bottom ash with an emphasis on heavy metal-bearing phases. Journal of Hazardous Materials, 187, 534–543. Wong, S.W.Y., Leung, P.T.Y., Djurisˇic´, A.B., Leung, K.M.Y., 2010. Toxicities of nano zinc oxide to five marine organisms: influences of aggregate size and ion solubility. Analytical and Bioanalytical Chemistry 396, 609–618. Wu, B., Wang, Y., Lee, Y.H., Horst, A., Wang, Z.P., Chen, D.R., Sureshkumar, R., Tang, Y.J.J., 2010. Comparative eco-toxicities of nano-ZnO particles under aquatic and aerosol exposure modes. Environmental Science & Technology 44, 1484–1489. Zhang, L.L., Jiang, Y.H., Ding, Y.L., Daskalakis, N., Jeuken, L., Povey, M., York, D., 2010. Mechanistic investigation into antibacterial behavior of suspensions of ZnO nanoparticles against E. coli. Journal of Nanoparticle Research 12, 1625– 163.

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