Chemical Speciation of Potentially Toxic Trace ... - ACS Publications

Jul 14, 2017 - Kingston Fly Ash Spill. Nelson Rivera,. §. Dean Hesterberg,. *. Navdeep Kaur, and Owen W. Duckworth. Department of Crop and Soil Scien...
0 downloads 0 Views 3MB Size
Subscriber access provided by UNIV OF DURHAM

Article

Chemical Speciation of Potentially Toxic Trace Metals in Coal Fly Ash Associated with the Kingston Fly Ash Spill Nelson A. Rivera, Dean Hesterberg, Navdeep Kaur, and Owen W. Duckworth Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.7b00020 • Publication Date (Web): 18 Jul 2017 Downloaded from http://pubs.acs.org on July 18, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Energy & Fuels is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

Chemical Speciation of Potentially Toxic Trace Metals in Coal Fly Ash Associated with the Kingston Fly Ash Spill

Nelson Rivera,§ Dean Hesterberg,* Navdeep Kaur, and Owen W. Duckworth

Department of Crop and Soil Science, Box 7620, North Carolina State University, Raleigh, North Carolina 27695-7620 USA §

Current Address: Department of Civil and Environmental Engineering, Box 90287, Duke University, Durham, North Carolina 27708, USA

Submitted in revised form Energy and Fuels July 14, 2017

*To whom correspondence should be addressed [email protected] Tel. (919) 513-3035 Fax. (919) 515-1267

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

Abstract: Coal ash released into the environment may release toxic trace elements into water,

2

sediments, and soils. The objective of this study was to characterize the chemical speciation of

3

As, Se, Cu, Zn, Cr, and U in coal fly ash samples related to the 2008 Kingston ash spill. Three

4

ash samples were analyzed using X-ray absorption spectroscopy (XAS) to determine oxidation

5

states or dominant species of trace-elements, which were previously found to range in

6

concentration from 8 to 20 mg kg-1. Linear combination fitting (LCF) of X-ray Absorption Near

7

Edge Structure (XANES) spectra from ash samples indicated that both reduced and oxidized

8

forms of the trace elements were present in the fly ash samples. We used the mineralogical

9

composition of the fly ash to select the most relevant standards for LCF fitting of XANES

10

spectra, which included metal-doped glasses, trace elements sorbed to iron oxy(hydroxides), and

11

pure mineral phases for each element. Arsenic K-edge XANES spectra were best fit as oxidized

12

As(V) (95–100%) associated with iron phases or aluminosilicate glass, where selenium K-edge

13

XANES spectra were fit as Se(IV) (77–86%) associated with glass, with lesser proportions of

14

Se(VI) and a more reduced Se species [fit as Se(0) or Se(II)S2]. Zinc K-edge XANES spectra

15

were best fit as Zn associated with ferrihydrite (70–77%), franklinite (ZnFe2O4, 8-12%), and

16

ZnO (14-20%). Qualitative assessment of U LIII-edge and Cr K-edge XANES spectra showed

17

dominances of U(VI) and Cr(III) oxidation states. Copper K-edge XANES data indicated the

18

possibility of both reduced and oxidized species, although our analysis could not fully account

19

for all spectral features. Our results revealed multiple species of each trace element in the fly ash

20

samples, which is important for predicting environmental mobility and bioavailability under the

21

range of geochemical conditions found in aquatic and terrestrial environments.

2

ACS Paragon Plus Environment

Page 2 of 33

Page 3 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

22

Energy & Fuels

1. INTRODUCTION

23

Fly ash contains trace elements and radionuclides,1 which has led to longstanding

24

concerns about the impacts of ash on aquatic and terrestrial ecosystems due to the large masses

25

of materials disposed or released into the environment.2,

26

toxicity of trace elements in coal fly ash are partially controlled by their chemical speciation. In

27

December 2008, 4.1-million cubic meters of fly ash were released into the Clinch, Emory, and

28

Tennessee Rivers from ash impoundment at the TVA Kingston (Tennessee, USA) Fossil Plant.

29

Ash samples associated with the release contain 8–200 mg kg-1 of As, U, Cr, Cu, Zn, and Se.4-6

30

Following cleanup operations, the total amounts of these potentially toxic trace metals in residual

31

ash left in the river sediments were estimated at 5–110 tonnes (Figure 1),5 raising concerns about

32

disturbance and redistribution of residual ash.7 Mobilization of these elements into the overlying

33

water or uptake into the aquatic food chain may pose a health risk to humans, wildlife, and the

34

aquatic ecosystem.4, 6, 8, 9 For example, selenium is an element of specific concern at the TVA

35

site, largely due to its potential toxicity to fish and waterfowl.10-12

36

3

The mobility, bioavailability, and

Coal fly ash from differing localities can vary in its composition and trace metal

37

concentrations.1,

13

38

transformations.14-21 In addition, trace elements may redistribute spatially in the resulting ash,

39

and form discrete solid phases, or adsorb or co-precipitate with major elements associated with

40

glassy or mineral matrices.22-25 For example, previous work suggests that fractions of As and Se

41

in coal evaporate during combustion, condensing by either heterogeneous nucleation on

42

refractory particles or homogeneous nucleation as submicron particles.17,

43

understand the chemical species of potentially toxic trace elements that form in fly ash to predict

44

their long-term mobility in aquatic environments of varying redox potential and pH.

During coal combustion, elements may undergo both redox and phase

3

ACS Paragon Plus Environment

23

It is important to

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

45

Our previous work5 demonstrated that more abundant Si, Al, Fe, Ca, Na, K, Mg, Ti, S,

46

and Ba in fly-ash samples associated with the TVA Kingston release mainly occur in

47

aluminosilicate glass, and crystalline phases such as quartz, mullite, anhydrite, and hematite.

48

Spatial distributions of trace elements were found to be highly heterogeneous on the sub-

49

microscale, with Sr being diffusely distributed and Cr, Zn, Pb, P, and U concentrated into hot

50

spots.5 Most of the past research on trace-element speciation in fly ash from the Kingston spill

51

has focused on oxidation states and short-range structural order of Hg, As, and Se.26, 27 We lack

52

knowledge of speciation of a broader array of environmentally relevant trace metals, including

53

their associations with both mineral and glassy phases. The objective of this research was to

54

determine the speciation of As, Se, Zn, Cr, U, and Cu in fly ash samples associated with the 2008

55

Kingston fly ash release. Synchrotron X-ray absorption spectroscopy was used to determine

56

oxidation states and model chemical species of these trace elements in fly ash. Understanding the

57

speciation of the trace metals in the fly ash may provide insights into the geochemical processes

58

that promote release of these trace metals into the environment, which may in turn help assess

59

long-term environmental impacts and public-health risks arising from future releases.

60 61

2. EXPERIMENTAL SECTION

62

2.1. Materials. Trace-element speciation was analyzed for three fly ash samples from

63

Tennessee Valley Authority (TVA) that were previously characterized for elemental composition

64

and macroelement speciation:5 two from the Kingston fossil plant (TVA-KIF-110110-F and

65

TVA-122208-7-7-J) and one from the Johnsonville plant (TVA-JVL-101910-A). Herein, we

66

refer to these samples as “KIF1”, “KIF2”, and “JVL”, respectively. The KIF1 and JVL samples

67

were collected directly from the electrostatic precipitator of each plant, and sample KIF2 was 4

ACS Paragon Plus Environment

Page 4 of 33

Page 5 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

68

collected in March 2009 from an intact portion of the failed ash storage cell responsible for the

69

2008 ash release into the Clint and Emory Rivers in Kingston, TN. Samples, which were dried

70

and stored at room temperature prior to analysis, were provided by TVA personnel as samples of

71

fresh and stored ash at the Kingston site, and have been utilized in other studies of ash

72

geochemistry to describe the potential heterogeneity of ash at the site.4,

73

contained 28–45 mg As kg-1, 6–9 mg Se kg-1, 130–200 mg Zn kg-1, 100–148 mg Cr kg-1, 8.9–12

74

mg U kg-1, and 101–194 mg Cu kg-1.5

5, 26-29

The samples

75

2.2. X-ray Absorption Spectroscopy (XAS). X-ray absorption near edge structure

76

(XANES) spectra for ash samples were collected at the National Synchrotron Light Source

77

(NSLS), Brookhaven National Laboratory (Upton, NY) and the Stanford Synchrotron Radiation

78

Light Source (SSRL). Spectra were collected at the K-edges of As, Se, Cu, and Zn at room

79

temperature in fluorescence mode using a 13-element Ge array detector and a Si(311) double

80

crystal monochromator (detuned by 30%) at NSLS Beamline X11A. Uranium M5-edge XANES

81

spectra were collected in fluorescence mode at Beamline X15B using a single-channel Ge solid

82

state detector, a Si(111) monochromator, and a He flight path. Standards for fitting analyses were

83

diluted in boron nitride (BN) to achieve a unit edge step for spectra that were typically collected

84

in transmission mode.30 Samples for U were mounted in acrylic holders and covered with 5-µm

85

thick polypropylene X-ray film to reduce absorption effects from tape adhesive. Beamline 4-3 at

86

SSRL was used to collect Cr K-edge XANES spectra in fluorescence mode using a Si(111)

87

variable-exit monochromator and a Vortex-ME4 four element silicon drift detector. Higher-order

88

harmonics were rejected by Rh-coated mirrors. Samples were mounted in polycarbonate holders

89

and covered with Kapton tape. Multiple spectra collected for each sample were merged to

90

improve the signal-to-noise ratio. No evidence for beam-induced sample damage was found in 5

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

91

successive scans. Supporting information Table S1 summarizes the parameters used in collecting

92

XAS spectra.

93

Details of data collection and analysis are discussed by Kelly et al.30 XANES spectra

94

were generally collected over three energy regions of -200 to -50 eV, -50 to 50 eV, and 50 to 300

95

eV relative to a given edge energy. Smaller step sizes and larger counting times were used in the

96

region bracketing the absorption edge (-50 to 50 eV). Energy calibrations for XANES spectra

97

were performed before data collection for each element and energy drift was monitored during

98

scans with a reference (see Table S1 for calibrants and energy). XANES data were aligned,

99

merged, baseline subtracted using a linear model, and normalized to an edge step of 1 using a

100

quadratic model in the IFEFFIT suite of computer programs31 interfaced with the Athena

101

software.32 Consistent ranges of energies were used for baseline subtraction and normalization

102

for all samples and standards of a given element. Models of chemical speciation of the selected

103

trace elements in the fly ash samples were developed using the linear combination fitting (LCF)

104

routine in Athena, which calculates the combinations of scaled spectra from our chosen standards

105

that sum to a fit to sample spectra.30 The final “best fits” reported here represent the lowest R-

106

factor (residual) computed by Athena as a statistical goodness of fit parameter.

107

The KIF1, KIF2, and JVL ash samples were predominantly composed of aluminosilicate

108

glasses (57–61% w/w) and crystalline phases (39–43% w/w) that included quartz (SiO2), mullite

109

(Al6Si2O13), anhydrite (CaSO4), lime (CaO), calcite (CaCO3), and iron (hydr)oxides.5 In addition

110

to the mineralogical composition from our previous publication, other characterizations showed

111

that the ash samples generally met the requirements of Class F fly ash by the ASTM C618

112

classification system.5 In short, class F fly ash has pozzolanic properties with contents of

113

aluminosilicates plus iron oxides greater than 70%.33 6

ACS Paragon Plus Environment

Page 6 of 33

Page 7 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

114

The above phases were considered to be the main sorbents for trace elements in our

115

speciation analysis along with discrete phases containing minerals or non-crystalline solids of a

116

given trace element. Based on the mineralogical composition of the fly ash, metal-doped glasses,

117

trace elements sorbed to iron oxy(hydroxides), and pure mineral phases for each element were

118

used in XANES fitting. A trace metal sorbed to a ferrihydrite phase was used as a proxy for the

119

iron phases. All standards used in the LCF fitting are listed in the supporting information.

120 121

3. RESULTS AND DISCUSSION

122

3.1. Arsenic. Arsenic in all fly ash samples was predominantly As(V), as shown by the

123

alignment of the white-line peaks in K-edge XANES spectra of the samples with that of As(V)

124

standards (Figure 2). Linear-combination fitting showed that the combination of our selected

125

standards yielding the best fit to the sample data included 62-65% of As(V) co-precipitated with

126

aluminosilicate glass and 30-38% of As(V) adsorbed on an iron phase (Table 1), with ~5%

127

As(III) present in the KIF2 sample from the failed storage cell. The results suggest that As(V)

128

was largely associated with the aluminosilicate glass that constitutes ~60% of these ash samples5,

129

and with Fe-(hydr)oxide phases such as hematite, spinels, or Fe(III)-enriched domains in the

130

glass (for which we used ferrihydrite as a surrogate sorbent).5 It should be noted that there is

131

little distinguishing structure in the white lines of the As(V) standards, and the main difference

132

between these spectra is a small energy shift in white line position (ca. 1 eV). These observations

133

suggest there may be some ambiguity in the fits with regard to the exact speciation of the As(V)

134

fraction. However, all three fits showed similar proportions of As(V)/glass and As(V)/iron oxide,

135

and these results agree with published XAS results showing that As(V) was the main oxidation

136

state in Class F fly ashes from other sources than used here.21, 34, 35An estimated 50 metric tons of 7

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 33

137

As remain in Clinch and Emory River sediments following cleanup of the TVA Kingston ash

138

spill (Figure 1). Sediment samples collected after the spill showed elevated concentrations of As

139

in porewaters.6,

140

Kingston ash in aqueous environments, thus posing a risk to the riverine ecosystems.4,

141

Arsenic(V), the dominant oxidation state in our samples, is generally less toxic and less mobile

142

than As(III) in most environments because it tends to adsorb strongly on Fe(III) and Al(III)

143

oxides.8,

144

measured at the TVA Kingston site.4, 6, 8, 28, 38

10, 37

8

In addition, leaching studies indicated that As can be mobilized from the 8, 36

However, reduction of As(V) to As(III) in reduced river sediments have been

145

3.2. Selenium. A comparison of Se K-edge XANES spectra for samples and standards

146

shows that Se(IV) (selenite) was the main oxidation state in our fly-ash samples (Figure 3).

147

However, a discernable shoulder on the lower energy side of the white line suggests the presence

148

of more reduced species. The XANES spectra of fly ash samples were best fit with spectra for

149

standards Se(IV) co-precipitated with glass standard (77–86% of total Se) along with 6–23% of

150

spectra from either Se(0) (elemental Se) or Se(II) in selenium sulfide (SeS2), and 90 mol%) form of Cr in our fly ash samples. The apparent lack ( 9,52 providing a pathway for

257

increased solubilization of trace elements associated with the glass (namely, Cu, Se, and As, as

258

suggested by our XANES results). Elements associated with iron phases may also be influenced

259

by the geochemical conditions of this environment. The alkaline pH may also favor the

260

desorption of oxyanions such as arsenate and selenite from surface sites of iron (hydr)oxides and

261

other sorbents.10 A study of aqueous and solid phase As speciation showed larger total dissolved

262

As total concentrations in pore waters (110 µg l-1) than in surface waters (3–13 µg l-1), as well as

263

a shift towards As(III) at greater depths in sediments.

264

embayments that contain residual fly ash from the spill show As concentrations ranging from

265

20–250 µg/L and Se concentrations from 5-40 µg/L when runoff from the surrounding area

266

interacts with the fly ash.54 In contrast, cations such as Cu and Zn should be retained at alkaline

267

pH, which promotes sorption to minerals or precipitation of insoluble (oxy)hydroxides.40 The

268

predicted behavior of this suite of trace elements thus illustrates the differing effects of

269

environmental conditions on the mobility of specific elements.

56

In fact, data from TVA monitoring of

270

4.2. Riverene and Riparian Sediments. Diluted ash mixed with sediments are also

271

found in the river or along its banks. In riverine and riparian sediments, we expect to see mildly

272

acidic to circumneutral pH and potentially reducing Eh.8 In contrast to concentrated ash deposits,

273

the alkaline components in fly ash such as carbonates will solubilize in acidic environments. Our

274

XANES fitting results gave no indication of trace elements associated with carbonates, so no co13

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 33

275

dissolution of carbonate and trace elements is expected. However, any trace element cations such

276

as Cu2+ and Zn2+ adsorbed on iron oxides, as suggested by our XANES fits of ferrihydrite-

277

associated cations (Table 1), would have a tendency to desorb from ash under increasingly acidic

278

sediment conditions. In contrast, oxyanions of As(V) and As(III) that appear to be associated

279

with Fe (hydr)oxides, should be less susceptible to desorption under acidic conditions. The

280

presence of reduced copper and copper-sulfide species in the fly ash implied by our XANES

281

analyses (Table 1) suggests that oxidative dissolution of copper would occur under oxic sediment

282

conditions. Chromium as solid-phase Cr(III) (Fig. 5A) should remain stable and insoluble under

283

oxid conditions because conversion of Cr(III) to Cr(VI) under oxic conditions is generally

284

kinetically slow.10, 57, 58. However, under certain conditions such as in the presence of MnO2 and

285

chelators, dissolution of Cr(III) oxide can occur and rapidly convert Cr(III) to Cr(VI).57-61

286

Anoxic redox conditions would promote reduction of oxidized trace-element species or

287

matrix minerals to which trace elements are bound. Arsenate and selenite are the dominant forms

288

of arsenic and selenium in the freshly generated ash, and these species can be reduced in riverine

289

sediments.10, 26, 36, 38, 39 Of particular concern would be the reduction of As(V) to As(III), and the

290

reductive dissolution of host Fe(III)-phases that may promote concomitant release of sorbed or

291

coprecipitated elements. Although our XANES results indicated that the primary solid-phase As

292

species is arsenate, pore water extracted from the sediments has been shown to contain arsenite,8,

293

38

294

arsenite under anoxic conditions.36 In contrast, selenium reduction from selenite to Se(0)/SeS2

295

would result in less soluble and less reactive Se forms under reducing conditions.10, 26, 36 Uranium

296

exists in the oxidized form of U(VI) (Fig. 5B), and similar to Se, reduction of U(VI) should

297

produce less soluble precipitates, mainly uraninite.46 Average dissolved concentrations of Se and

and incubations conducted with sediment/ash mixtures show that arsenate can be reduced to

14

ACS Paragon Plus Environment

Page 15 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

298

U in pore water samples of sediments affected by the Kingston ash spill ranged from 0.3–2 µg Se

299

L-1 and 0.2–3 µg U L-1.8 Moreover, Cr(III) would not be expected to be mobilized under

300

reducing conditions.

301

The geochemical complexity of trace elements in the fly ash samples analyzed here

302

indicates that direct ecotoxicological assessments of potentially toxic trace elements should

303

consider chemical conditions in relation to the chemical speciation of target trace elements of

304

concern along with dominant matrix elements such as iron, aluminum, and silicon in oxides or

305

glasses with which trace elements are associated. In river sediments and other environmental

306

systems, the geochemical conditions in which fly ash resides are important for controlling trace

307

metal mobility and potential toxicity.

308 309

Acknowledgments. This work was supported by a Tennessee Valley Authority/Oak Ridge

310

Associated Universities Characterization and Environmental Effects of Coal Combustion

311

Products Grant (No. 7-22978). We thank Dr. Neil Carriker for valuable discussion and for

312

providing ash samples. We thank Dr. David Buchwalter for valuable discussion. We thank Drs.

313

Kaumudi Pandya, Paul Northrup, and Maria Hernandez-Soriano for assistance at the National

314

Synchrotron Light Source and John Bargar, Erik Nelson, Matthew Lattimer, and Martin Akafia

315

for assistance at the Stanford Synchrotron Radiation Lightsource. We thank Dr. Markus Gräfe

316

(CSIRO) for providing Cu K-edge XANES data for standards: CuFeS2, CuFe2S3 and CuS2 and

317

Paul Northrup for the U standards. Portions of this research were carried out at the National

318

Synchrotron Light Source (NSLS), Brookhaven National Laboratory, which is supported by the

319

U.S. Department of Energy, Division of Materials Science and Division of Chemical Services.

320

Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 15

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 33

321

is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy

322

Sciences under Contract No. DE-AC02-76SF00515.

323 324

SUPPORTING INFORMATION AVAILABLE

325

Supporting information includes synthesis details for aluminosilicate glass standards,

326

standards used in linear combination fitting, as well as parameters used in collecting XAS

327

spectra. . This information is available free of charge via the Internet at http://pubs.acs.org/.

328

16

ACS Paragon Plus Environment

Page 17 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

REFERENCES 1.

Hatch, J. R.; Bullock, J. H.; Finkelman, R. B. Open File Report 2006-1162: Chemical

Analyses of Coal, Coal-Associated Rocks and Coal Combustion Products Collected for the National Coal Quality Inventory USGS: Reston, VA, 2006. 2.

Carlson, C. L.; Adriano, D. C., Environmental impacts of coal combustion residues. .

Journal of Environmental Quality 1993, 22, 227-247. 3.

Harkness, J. S.; Sulkin, B.; Vengosh, A., Evidence for Coal Ash Ponds Leaking in the

Southeastern United States. Environmental Science & Technology 2016, 50, (12), 6583-6592. 4.

Bednar, A. J.; Chappell, M. A.; Seiter, J. M.; Stanley, J. K.; Averett, D. E.; Jones, W. T.;

Pettway, B. A.; Kennedy, A. J.; Hendrix, S. H.; Steevens, J. A., Geochemical investigations of metals release from submerged coal fly ash using extended elutriate tests. Chemosphere 2010, 81, (11), 1393-1400. 5.

Rivera, N.; Kaur, N.; Hesterberg, D.; Ward, C. R.; Austin, R. E.; Duckworth, O. W.,

Chemical composition, speciation, and elemental associations in coal fly ash samples related to the kingston ash spill. Energy & fuels 2015, 29, (2), 954-967. 6.

Ruhl, L.; Vengosh, A.; Dwyer, G. S.; Hsu-Kim, H.; Deonarine, A.; Bergin, M.;

Kravchenko, J., Survey of the Potential Environmental and Health Impacts in the Immediate Aftermath of the Coal Ash Spill in Kingston, Tennessee. Environmental Science & Technology 2009, 43, (16), 6326-6333. 7.

Cowan, E. A.; Gaspari, D. P.; Brachfeld, S. A.; Seramur, K. C., Characterization of coal

ash released in the TVA Kingston spill to facilitate detection of ash in river systems using magnetic methods. Fuel 2015, 159, 308-314.

17

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

8.

Page 18 of 33

Ruhl, L.; Vengosh, A.; Dwyer, G. S.; Hsu-Kim, H.; Deonarine, A., Environmental

Impacts of the Coal Ash Spill in Kingston, Tennessee: An 18-Month Survey. Environmental Science & Technology 2010, 44, (24), 9272-9278. 9.

Ruhl, L.; Vengosh, A.; Dwyer, G. S.; Hsu-Kim, H.; Schwartz, G.; Romanski, A.; Smith,

S. D., The Impact of Coal Combustion Residue Effluent on Water Resources: A North Carolina Example. Environmental Science & Technology 2012, 46, (21), 12226-12233. 10.

Adriano, D. C., Bioavailability of Trace Metals. In Trace Elements in Terrestrial

Environments, Springer New York: 2001; pp 61-89. 11.

Lemly, A. D., Symptoms and implications of selenium toxicity in fish: the Belews Lake

case example. Aquatic Toxicology 2002, 57, (1–2), 39-49. 12.

Lemly, A. D., Teratogenic effects and monetary cost of selenium poisoning of fish in

Lake Sutton, North Carolina. Ecotoxicology and Environmental Safety 2014, 104, 160-167. 13.

Mattigod, S. V.; Rai, D.; Eary, L. E.; Ainsworth, C. C., Geochemical factors controlling

the mobilization of inorganic constituents from fossil-fuel combustion residues. 1. Review of the major elements. Journal of Environmental Quality 1990, 19, (2), 188-201. 14.

Yudovich, Y. E.; Ketris, M. P., Arsenic in coal: a review. International Journal of Coal

Geology 2005, 61, (3–4), 141-196. 15.

Yudovich, Y. E.; Ketris, M. P., Selenium in coal: A review. International Journal of Coal

Geology 2006, 67, (1-2), 112-126. 16.

Huffman, G. P.; Huggins, F. E.; Shah, N.; Zhao, J., Speciation of arsenic and chromium

in coal and combustion ash by XAFS spectroscopy. Fuel Processing Technology 1994, 39, (1), 47-62.

18

ACS Paragon Plus Environment

Page 19 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

17.

Shoji, T.; Huggins, F. E.; Huffman, G. P.; Linak, W. P.; Miller, C. A., XAFS

spectroscopy analysis of selected elements in fine particulate matter derived from coal combustion. Energy & fuels 2002, 16, (2), 325-329. 18.

Huggins, F. E.; Najih, M.; Huffman, G. P., Direct speciation of chromium in coal

combustion by-products by X-ray absorption fine-structure spectroscopy. Fuel 1999, 78, (2), 233-242. 19.

Shah, P.; Strezov, V.; Stevanov, C.; Nelson, P. F., Speciation of arsenic and selenium in

coal combustion products. Energy & fuels 2007, 21, (2), 506-512. 20.

Stam, A. F.; Meij, R.; te Winkel, H.; Eijk, R. J. v.; Huggins, F. E.; Brem, G., Chromium

Speciation in Coal and Biomass Co-Combustion Products. Environmental Science & Technology 2011, 45, (6), 2450-2456. 21.

Luo, Y.; Giammar, D. E.; Huhmann, B. L.; Catalano, J. G., Speciation of Selenium,

Arsenic, and Zinc in Class C Fly Ash. Energy & fuels 2011, 25, (7), 2980-2987. 22.

Linak, W. P.; Wendt, J. O. L., Trace metal transformation mechanisms during coal

combustion. Fuel Processing Technology 1994, 39, (1), 173-198. 23.

Vejahati, F.; Xu, Z.; Gupta, R., Trace elements in coal: Associations with coal and

minerals and their behavior during coal utilization – A review. Fuel 2010, 89, (4), 904-911. 24.

Eary, L. E.; Rai, D.; Mattigod, S. V.; Ainsworth, C. C., Geochemical Factors Controlling

the Mobilization of Inorganic Constituents from Fossil Fuel Combustion Residues: II. Review of the Minor Elements. Journal of Environmental Quality 1990, 19, (2), 202-214. 25.

Hulett, L. D.; Weinberger, A. J.; Northcutt, K. J.; Ferguson, M., Chemical species in fly

ash from coal burning power plants. Science 1980, 210, (4476), 1356-1358.

19

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

26.

Page 20 of 33

Chappell, M. A.; Seiter, J. M.; Bednar, A. J.; Price, C. L.; Averett, D.; Lafferty, B.;

Tappero, R.; Stanley, J. S.; Kennedy, A. J.; Steevens, J. A.; Zhou, P.; Morikawa, E.; Merchan, G.; Roy, A., Stability of solid-phase selenium species in fly ash after prolonged submersion in a natural river system. Chemosphere 2014, 95, (0), 174-181. 27.

Liu, Y.-T.; Chen, T.-Y.; Mackebee, W. G.; Ruhl, L.; Vengosh, A.; Hsu-Kim, H.,

Selenium Speciation in Coal Ash Spilled at the Tennessee Valley Authority Kingston Site. Environmental Science & Technology 2013, 47, (24), 14001-14009. 28.

Bednar, A. J.; Averett, D. E.; Seiter, J. M.; Lafferty, B.; Jones, W. T.; Hayes, C. A.;

Chappell, M. A.; Clarke, J. U.; Steevens, J. A., Characterization of metals released from coal fly ash during dredging at the Kingston ash recovery project. Chemosphere 2013, 92, (11), 15631570. 29.

Cowan, E. A.; Seramur, K. C.; Hageman, S. J., Magnetic susceptibility measurements to

detect coal fly ash from the Kingston Tennessee spill in Watts Bar Reservoir. Environ Pollut 2013, 174, 179-88. 30.

Kelly, S.; Hesterberg, D.; Ravel, B., Analysis of soils and minerals using x-ray absorption

spectroscopy. In Methods of Soil Analysis. Part 5. Mineralogical Methods., Ulery, A. L.; Drees, R., Eds. Soil Science Society of America: Madison, WI, 2008; pp 387-463. 31.

Newville, M., FEFFIT: Interactive XAFS analysis and FEFF fitting. . Journal of

Synchrotron Radiation 2001, 8, 322-324. 32.

Ravel, B.; Newville, M., ATHENA, ARTEMIS, HEPHAESTUS: Data analysis for X-ray

absorption spectroscopy using IFEFFIT. Journal of Synchrotron Radiation 2005, 12, 537-541.

20

ACS Paragon Plus Environment

Page 21 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

33.

American Society for Testing and Materials (1988). Standard specifications for fly ash

and raw or calcined natural pozzolon for use as a mineral admixture in Portland cement concrete. C618-88. ASTM, Philadelphia, PA. 34.

Catalano, J. G.; Huhmann, B. L.; Luo, Y.; Mitnick, E. H.; Slavney, A.; Giammar, D. E.,

Metal Release and Speciation Changes during Wet Aging of Coal Fly Ashes. Environmental Science & Technology 2012, 46, (21), 11804-11812. 35.

Huggins, F. E.; Senior, C. L.; Chu, P.; Ladwig, K.; Huffman, G. P., Selenium and arsenic

speciation in fly ash from full-scale coal-burning utility plants. Environmental Science & Technology 2007, 41, (9), 3284-3289. 36.

Schwartz, G. E.; Rivera, N.; Lee, S. W.; Harrington, J. M.; Hower, J. C.; Levine, K. E.;

Vengosh, A.; Hsu-Kim, H., Leaching potential and redox transformations of arsenic and selenium in sediment microcosms with fly ash. Applied Geochemistry 2016, 67, 177-185. 37.

Thomas, D. J., Arsenic toxicity in humans: Research problems and prospects.

Environmental Geochemistry and Health 1994, 16, (3), 107-111. 38.

Rogers, W. J.; Carriker, N. E.; Vitale, R. J.; Gable, J. N.; Rodgers, E. E.; Kraycik, J. P. In

Porewater Studies Subsequent to the Kingston Ash Event World of Coal Ash, Lexington, Kentucky, April 22-25, 2013; Lexington, Kentucky, 2013. 39.

Conley, J. M.; Funk, D. H.; Hesterberg, D. H.; Hsu, L.-C.; Kan, J.; Liu, Y.-T.;

Buchwalter, D. B., Bioconcentration and Biotransformation of Selenite versus Selenate Exposed Periphyton and Subsequent Toxicity to the Mayfly Centroptilum triangulifer. Environmental Science & Technology 2013, 47, (14), 7965-7973. 40.

McBride, M. B., Reactions Controlling Heavy Metal Solubility in Soils. In Advances in

Soil Science, Stewart, B. A., Ed. Springer New York: 1989; Vol. 10, pp 1-56. 21

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

41.

Page 22 of 33

Schultz, M. F.; Benjamin, M. M.; Ferguson, J. F., Adsorption and desorption of metals on

ferrihydrite: reversibility of the reaction and sorption properties of the regenerated solid. Environmental Science & Technology 1987, 21, (9), 863-869. 42.

Bartlett, R. J.; James, B. R., Redox Chemistry of Soils. In Advances in Agronomy,

Donald, L. S., Ed. Academic Press: 1993; Vol. Volume 50, pp 151-208. 43.

Bannister, W. H., The biological chemistry of the elements: The inorganic chemistry of

life: By J J R Fraústo da Silva and R J P Williams. pp 561. Clarendon Press, Oxford. 1991. £60 ISBN 0-19-855598-9. Biochemical Education 1992, 20, (1), 62-63. 44.

Richard, F. C.; Bourg, A. C. M., Aqueous geochemistry of chromium: A review. Water

Research 1991, 25, (7), 807-816. 45.

Silva, R. J.; Nitsche, H., Actinide Environmental Chemistry. Radiochimica Acta 1995,

70/71, 377-396. 46.

Bargar, J. R.; Bernier-Latmani, R.; Giammar, D. E.; Tebo, B. M., Biogenic Uraninite

Nanoparticles and Their Importance for Uranium Remediation. Elements 2008, 4, (6), 407-412. 47.

O'Loughlin, E. J.; Kelly, S. D.; Cook, R. E.; Csencsits, R.; Kemner, K. M., Reduction of

Uranium(VI) by Mixed Iron(II)/Iron(III) Hydroxide (Green Rust):  Formation of UO2 Nanoparticles. Environmental Science & Technology 2003, 37, (4), 721-727. 48.

McKeown, D. A., X-ray-absorption near-edge structure of transition-metal zinc-blende

semiconductors: Calculation versus experimental data and the pre-edge feature. Physical Review B 1992, 45, (6), 2648-2653. 49.

Kau, L. S.; Spira-Solomon, D. J.; Penner-Hahn, J. E.; Hodgson, K. O.; Solomon, E. I., X-

ray absorption edge determination of the oxidation state and coordination number of copper.

22

ACS Paragon Plus Environment

Page 23 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

Application to the type 3 site in Rhus vernicifera laccase and its reaction with oxygen. Journal of the American Chemical Society 1987, 109, (21), 6433-6442. 50.

Pearce, C. I.; Pattrick, R. A. D.; Vaughan, D. J.; Henderson, C. M. B.; van der Laan, G.,

Copper oxidation state in chalcopyrite: Mixed Cu d9 and d10 characteristics. Geochimica et Cosmochimica Acta 2006, 70, (18), 4635-4642. 51.

Font, O.; Querol, X.; Huggins, F. E.; Chimenos, J. M.; Fernández, A. I.; Burgos, S.; Peña,

F. G., Speciation of major and selected trace elements in IGCC fly ash. Fuel 2005, 84, (11), 1364-1371. 52.

Bunker, B. C., Molecular mechanisms for corrosion of silica and silicate glasses. Journal

of Non-Crystalline Solids 1994, 179, (0), 300-308. 53.

Kulczycki, E.; Fowle, D. A.; Knapp, C.; Graham, D. W.; Roberts, J. A., Methanobactin-

promoted dissolution of Cu-substituted borosilicate glass. Geobiology 2007, 5, (3), 251-263. 54.

Authority, T. V. Kingston Ash Recovery Project Non-Time-Critical Removal Action for

the River System Long-term Monitoring Sampling and Analysis Plan (SAP); 2013. 55.

Scott, S. H. Impact of Flood Flows on Residual Fly ash Distribution in the Emory,

Clinch, and Tennessee River Reaches of Watts Bar Reservoir; Coastal and Hydraulics Laboratory: 2014. 56.

Jackson, B. P.; Seaman, J. C.; Hopkins, W., Arsenic speciation in a fly ash settling basin

system. In Chemistry of trace elements in fly ash, Sajwan, K. S.; Alva, A. K.; Keefer, R. F., Eds. Kluwer Academic/Plenum Publishers: NY, 2003; pp 203-218. 57.

Apte, A. D.; Tare, V.; Bose, P., Extent of oxidation of Cr(III) to Cr(VI) under various

conditions pertaining to natural environment. Journal of Hazardous Materials 2006, 128, (2–3), 164-174. 23

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

58.

Page 24 of 33

Duckworth, O. W.; Akafia, M. M.; Andrews, M. Y.; Bargar, J. R., Siderophore-promoted

dissolution of chromium from hydroxide minerals. Environmental Science: Processes & Impacts 2014, 16, (6), 1348-1359. 59.

Carbonaro, R. F.; Gray, B. N.; Whitehead, C. F.; Stone, A. T., Carboxylate-containing

chelating agent interactions with amorphous chromium hydroxide: Adsorption and dissolution. Geochimica et Cosmochimica Acta 2008, 72, (13), 3241-3257. 60.

Carbonaro, R. F.; Stone, A. T., Oxidation of CrIII aminocarboxylate complexes by

hydrous manganese oxide: products and time course behaviour. Environmental Chemistry 2015, 12, (1), 33-51. 61.

Oze, C.; Bird, D. K.; Fendorf, S., Genesis of hexavalent chromium from natural sources

in soil and groundwater. Proc Natl Acad Sci U S A 2007, 104, (16), 6544-9.

24

ACS Paragon Plus Environment

Page 25 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

FIGURES Figure 1. Total mass selected trace elements from fly ash residuum. The total fly ash remaining is estimated to be 380,000 metric tons. Calculations assume a specific gravity of 2.3 and trace element concentrations from previous studies.5, 7 Figure 2. Stacked, normalized As K-edge XANES spectra for coal fly ash samples KIF1, KIF2, and JVL and selected As standards. Best fits to the sample spectra (overlaid solid lines) over the range of 11850 and 11890 eV for As were obtained with linear combinations of As(V) incorporated into glass, As(V) adsorbed to ferrihydrite (Fh), and/or As(III) adsorbed to ferrihydrite (Fh). Figure 3. Stacked, normalized Se K-edge XANES for coal fly ash samples KIF1, KIF2, and JVL and selected Se standards. Best fits to the sample spectra (overlaid solid lines) over the range of 12650 and 12680 eV were obtained with linear combinations of selenite incorporated into glass, selenium sulfide or Se0, and/or Na-selenate. Figure 4. Stacked, normalized Zn K-edge XANES spectra for coal fly ash samples KIF1, KIF2, and JVL and selected Zn standards. Best fits to the sample spectra (overlaid solid lines) over a range of 9650 and 9700 eV included Zn incorporated into glass, ZnO, Sphalerite ((Zn,Fe)S), Zn sorbed to ferrihydrite (Fh), and/or franklinite (ZnFe2O4). Figure 5. (A) Stacked, normalized Cr K-edge XANES and (B) U M5-edge XANES spectra for coal fly ash samples KIF1, KIF2, and JVL and selected Cr and U standards. The Cr oxidation state is predominantly +3 because the fly ash samples lack the prominent pre-edge feature associated with a +6 oxidation state (vertical dashed line). For U, all samples show a peak position consistent with a U in +6 oxidation state. Figure 6. (A) Stacked, normalized Cu K-edge XANES spectra and (B) derivative XANES spectra for coal fly ash samples KIF1, KIF2, and JVL and selected Cu standards. Best fits to the sample spectra (overlaid solid lines) were computed over an energy range of 8970 to 9020 eV for Cu, and included linear combinations of Cu(II) incorporated into glass, Cu2O, chalcopyrite (CuFeS2), and Cu2S. Fitting with our available standards did not account for the pre-white line feature (see dashed vertical line) in fly ash spectra. This feature is indicative of a reduced copper species. Figure 7. Conceptual model of pH and redox conditions favoring leaching and diffusion of trace elements from fly ash.

25

ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 33

Table 1. Results of linear combination fitting (LCF) showing combinations of standards yielding the best fits to arsenic, selenium, copper, and zinc K-edge XANES spectra for fly-ash samples KIF1, KIF2, and JVL. Included are spectral weighting factors on standards (%) ± uncertainties and residuals in the fits (R factors). Fits were performed across energy ranges of 11850-11890 eV (As), 12650-12680 eV (Se), 8970-9020 eV (Cu), and 9650-9700 eV (Zn). Element/Sample Arsenic As(V)/glass KIF1 64 ± 7 KIF2 65 ± 6 JVL 62 ± 8 Selenium Se(0)/SeS2 KIF1 23 ± 1 KIF2 12 ± 3 JVL 6±2 Copper Cu2O KIF1 27 ± 3 KIF2 20 ± 8 JVL 22 ± 8 Zinc ZnO KIF1 14 ± 1 KIF2 20 ± 1 JVL 17 ± 1

XANES Individual components (%)a As(V)/Fh As(III)/Fhb 36 ± 8 30 ± 7 5±2 38 ± 8 Se(IV)/Glass Na-Selenate 77 ± 2 80 ± 2 8±2 86 ± 2 8±2 Cu2S Chalcopyrite Cu-glass CuO 14 ± 3 42 ± 5 17 ± 8 41 ± 8 20 ± 9 19 ± 13 36 ± 8 13 ± 8 29 ± 11 Zn/Fhb Franklinite 77 ± 4 9±3 72 ± 3 8±3 70 ± 3 12 ± 3 b

a

R-factorc 0.01 0.01 0.02 0.01 0.03 0.01 0.02 0.02 0.02 0.001 0.002 0.002

Sum of the data values of individual components (%) are normalized to 100. R-factor = ∑(data – fit)2 / ∑(data2); As(III) , As(V), or Zn sorbed to ferrihydrite; cParameter uncertainties calculated by Athena are given in parenthesis;

26

ACS Paragon Plus Environment

Page 27 of 33

Figure 1.

70 Mass (Metric tons)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Energy & Fuels

60

60

60

Zn

Cu

50

50 40

40 30

30 20 10 0

5 Se

9 U

Pb

Cr

As

ACS Paragon Plus Environment

Energy & Fuels

Figure 2.

As(III)/Fh

Normalized XANES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

As(V)/Fh

As(V)/Glass As2O5 JVL KIF2 KIF1 11860 11870 11880 X-ray Energy (eV) ACS Paragon Plus Environment

Page 28 of 33

Page 29 of 33

Figure 3.

Na-Selenate

Se(IV)/Glass

Normalized XANES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

SeS2 Se(0)

JVL KIF2 KIF1 12650

12660 12670 X-ray Energy (eV)

ACS Paragon Plus Environment

12680

Energy & Fuels

Figure 4.

Zn-Glass Sphalerite

ZnO Normalized XANES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 33

Franklinite Zn/Fh

JVL KIF2 KIF1

9650 9660 9670 9680 9690 9700 X-ray Energy (eV) ACS Paragon Plus Environment

Page 31 of 33

Energy & Fuels

Figure 5.

A

B

K2Cr2O7

U(IV)

10% Cr(VI)/90% Cr(III)

Cr2O3

JVL

KIF2

Normalized XANES

50% Cr(VI)/50% Cr(III)

Normalized XANES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

KIF1

U(VI)

JVL

KIF2 KIF1

5980 6000 6020 6040 6060 6080 3540 ACS Paragon Plus Environment X-ray Energy (eV)

3550 3560 X-ray Energy (eV)

Energy & Fuels

Figure 6. A

B

CuO

Cu2S Chalcopyrite Cu2O JVL

First Derivative XANES

Cu2+/Glass

Normalized XANES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Page 32 of 33

KIF2 KIF1

8980 9000 X-ray Energy (eV)

9020

ACS Paragon Plus Environment

8980 8990 X-ray Energy (eV)

Page 33 of 33

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Energy & Fuels

Figure 7.

ACS Paragon Plus Environment