Using Lead Isotopes To Assess Source and Migration of Lead during

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Using Lead Isotopes to Assess Source and Migration of Lead during Thermal Treatment of Municipal Solid Waste Influenced by Air Excess Ratio LI-Ming Shao, Yang Li, Hua Zhang, and Pin-Jing He Energy Fuels, Just Accepted Manuscript • Publication Date (Web): 11 Jan 2018 Downloaded from http://pubs.acs.org on January 11, 2018

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Pb isotopic approach was very useful for gaining a better understanding of the migration behavior of Pb from individual waste components during the complicated high temperature process. 85x47mm (251 x 251 DPI)

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1

Using Lead Isotopes to Assess Source and Migration of Lead during Thermal

2

Treatment of Municipal Solid Waste Influenced by Air Excess Ratio

3

Li-Ming Shao 1,2,3,4, Yang Li 1,2,4, Hua Zhang 1,2,4*, Pin-Jing He 2,3,4

4

1

5

Shanghai 200092, China

6

2

7

China

8

3

9

Towns & Rural Area, Ministry of Housing Urban-Rural Development, Shanghai

State Key Laboratory of Pollution Control and Resource Reuse, Tongji University,

Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092,

Centre for the Technology Research and Training on Household Waste in Small

10

200092, China

11

4

12

China

13

* Corresponding to: [email protected]

Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092,

14 15

Abstract

16

The behavior of lead (Pb) during thermal treatment of municipal solid waste (MSW)

17

is a serious environmental concern. The migration of Pb during pilot-scale thermal

18

treatment of MSW with controlled air excess ratio (ER) was studied focusing on Pb

19

contents and isotope ratios analysis. Different ERs showed different Pb distribution

20

behaviors in fly ash (FA) from MSW incineration, owing to the change of Pb

21

migration from different MSW components. Although the Pb contents in FA under the

22

oxidizing condition increased significantly with the increase of ER (almost 100%


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from ER = 1.0 to ER = 1.3), the major sources (i.e., papers and plastics) contributing

24

Pb to FA were similar based on the Pb isotope identification. This suggested that the

25

migration of Pb from these MSW components was promoted in a high oxygen

26

environment. In contrast, the Pb contents in FA under the low oxygen condition (ER =

27

0.3−0.5) were similar, and rubbers became the major source of Pb in FA in the low

28

oxygen environment instead of papers. In the low oxygen environment the migration

29

of Pb in rubbers and papers was promoted and inhibited, respectively, as indicated by

30

the isotopic analysis combined with the micro-X-ray fluorescence and diffraction

31

analyses.

32

Keywords: thermal treatment, Pb migration, Pb isotopic approach, source

33

identification

34 35

1. Introduction

36

Industrial point sources (e.g., coal combustion, metal smelting, and waste

37

thermal treatment) are the major anthropogenic lead (Pb) inputs into the environment

38

1

39

evaporate into flue gas and condense onto the fly ash (FA), a small part of which

40

might escape from the precipitators into the environment and cause pollution. Studies

41

have focused extensively on the migration of Pb during the high-temperature

42

processes for its emission control 2. In laboratory-scale thermal treatment experiments,

43

the influencing factors such as temperature, atmosphere, chloride and other

44

compounds in the feedstocks have been investigated for their effects on Pb migration

. During such high-temperature treatment processes, Pb in the input materials can


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by controlling the change of other influencing factors and based on the partitioning of

46

Pb in the products 3, 4. For example, it was found that the migration of Pb from waste

47

to flue gas could be greatly promoted in the presence of chlorine

48

ways by which the source speciation and distribution of Pb in various feedstocks

49

determine Pb transformation and transfer at different reducing or oxidizing conditions

50

are unclear, due to the difficulties in identifying trace Pb compounds and determining

51

their respective migration.

5, 6

. However, the

52

Stable isotope analysis has become a novel and powerful tool to trace process

53

and sources of heavy metals and determine their reaction mechanisms as well as the

54

influencing factors during many processes by providing characteristic “fingerprint”

55

signatures

56

multiple chromium (Cr) removal mechanisms were evident by Cr isotope

57

measurements

58

predominant factor (litter biomass production) in atmospheric Hg inputs to the forest

59

floor

60

particulate matter, sediments, solid waste, soils, etc. were investigated

61

impacts of industrial emission, sediment contamination, etc. to the environment and

62

human health were evaluated 15-17. These studies indicated that the variation of stable

63

isotopic composition during various processes is a decisive condition for the

64

application of the stable isotope analysis method.

65 66

7-9

. Jamieson-Hanes et al. reported that during groundwater remediation,

10

. Wang et al. used mercury (Hg) isotopes to determine the

11

. On the basis of stable Pb isotope ratios, the sources of Pb in atmospheric 12-14

, and the

Thermal treatment of solid waste is one of the major sources of Pb release into the environment

12

. The migration of Pb during this process is more complex than


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during other high-temperature processes, such as coal combustion, because various

68

forms of heavy metals are contained in the multi-component feedstock. Many

69

researchers have studied the parameters influencing the migration of Pb during

70

municipal solid waste (MSW) thermal treatment, including redox atmosphere

71

temperature 14, and the presence of chloride 15, sulfur 4, and other mineral substances

72

16

73

significantly under different oxygen conditions, because of different speciation of Pb

74

in MSW components, which was affected by the redox atmosphere 17, 18. It is difficult

75

to identify the contributions of different MSW components to the Pb migration into

76

flue gas or fly ash during the thermal treatment process under the various oxygen

77

conditions that may occur in incinerators.

13

,

.Therein, the migration of Pb on a total content basis was found to change

78

Our previous study confirmed the feasibility of using the Pb isotopic approach in

79

the source identification of Pb during laboratory-scale thermal treatment simulated by

80

a tube furnace experiment

81

differences in the reaction conditions that occur in laboratory-scale equipment, as well

82

as in feedstock waste compositions. In this study, therefore, a pilot-scale incinerator

83

was adopted to investigate (using Pb isotopic analysis) the migration of Pb during

84

thermal treatment by controlling air excess ratios (ER) of MSW collected from a

85

transfer station as the feedstock. The objectives were to determine the major sources

86

(contribution of MSW components) of Pb in FA and the influence of different oxygen

87

environments on the migration of Pb.

19

. Compared to actual waste incinerators, there are great

88


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2. Material and methods

90

2.1 Waste samples and air pollution control residues

91

The MSW samples (MSW1, MSW2, and MSW3) were collected from three

92

MSW transfer stations in different areas of Shanghai, China from September 2014 to

93

April 2015. The transfer stations process above 2000 tons of MSW daily, in which

94

MSW was unloaded from the collection vehicles. By means of coning and quartering,

95

sub-samples (approximately 15 kg for each) of the collected MSW samples were

96

prepared. Food and fruit wastes (FW), glass (GL), metals (ME), papers (PA), plastics

97

(PL), rubbers (RU), textiles (TE), and woods (WO) were separated from the

98

sub-samples

99

overnight and their moisture contents were determined. The physical compositions of

100

the three MSW samples are shown in Figure 1, and the characteristics of the MSW1

101

sample, which was used in the pilot-scale thermal treatment experiment, are shown in

102

Table S1 in the Supporting Information. The dried samples were ground using an

103

ultra-centrifugal mill (ZM200, Retsch Technology, Germany) into a particle size < 2

104

mm prior to analysis.

20

. All of these MSW components were dried in an oven at 65 ºC

105

The air pollution control residues (APCR), denoted as A1, A2, and A3, were

106

collected from three large-scale (treatment capacities of 1000−3000 t/d) MSW

107

incineration plants in Shanghai in 2013, 2015, and 2016, respectively. Those plants

108

were equipped with grate furnaces and semi-dry air pollution control systems (lime

109

slurry injection + activated carbon + bag filter, or lime slurry injection + activated

110

carbon + bag filter + wet scrubber), and the ER was 1.5−2.0. All the APCR samples


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were dried in an oven at 105 ºC for 24 h and ground to a particle size < 150 µm.

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2.2 Pilot-scale thermal treatment experiment

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The thermal treatment simulation experiment was conducted in the pilot-scale

114

incinerator illustrated in Figure S1 in the Supporting Information. The incinerator

115

consists of four systems: feeding, combustion (two combustion chambers), heat

116

exchange, and flue gas treatment. To control the redox atmosphere, the two

117

combustion chambers have individual air distribution systems. The waste (MSW1),

118

which is more evenly distributed, was continuously fed into the primary combustion

119

chamber (equipped with reciprocating grate) by a screw feeder at a rate of 450 kg/h.

120

The volatile matters emitted from the primary combustion chamber were further

121

combusted in the secondary chamber. In each test, the operating temperature was 900

122

ºC, and the stable running time exceeded 2.5 h. The FA samples were collected by an

123

FA collector from the top of primary combustion chamber and the front of secondary

124

air distribution system. To evaluate the effect of atmosphere on the migration of heavy

125

metals during the thermal treatment process, the ERs of the primary air distribution

126

system, as a stoichiometric ratio, varied from 0.3 to 1.3 (0 < ER < 1 indicates that the

127

combustion occurs under reducing conditions and ER ≥ 1 indicates oxidizing

128

conditions) 21.

129

2.3 Analysis of heavy metal contents and stable Pb isotope ratios

130

The MSW components, APCR, and FA samples were digested in triplicate using

131

concentrated HNO3-HF-HClO4-H2O2 in a hot-plate based digestion method 19. Heavy

132

metal concentrations in the diluted digestion solutions of the waste and ash samples


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were measured using an inductively coupled plasma optical emission spectrometer

134

(ICP-OES, 720ES, Agilent Scientific Technologies Ltd., USA) and an inductively

135

coupled plasma mass spectrometer (ICP-MS, Agilent-7700, Agilent Scientific

136

Technologies Ltd., USA), respectively.

137

Before conducting the stable Pb isotopic analysis, the digestion solutions of the

138

waste and ash samples were purified using micro exchange columns with AG1 X8

139

(100−200 mesh) anion exchange resin referring to Strelow et al.

140

recovery ratios of Pb ranged from 88% to 106%. The total Pb blank for the procedure

141

was lower than 100 pg. The Pb isotope ratios in the purified solutions were

142

determined using a multi-collector inductively coupled plasma mass spectrometer

143

(MC-ICP-MS, Nu Plasma, Nu Instruments Ltd., UK). The Pb isotopic standard

144

SRM-981 and Tl standard SRM-997 (203Tl/205Tl = 2.3889) solutions were measured

145

every five samples to determine and update the ratio correction factors

146

measured

147

15.490−15.494 and 36.696−36.707, respectively) of SRM-981 matched the certified

148

values of 16.940, 15.496 and 36.722, respectively 24.

206

Pb/204Pb,

207

Pb/204Pb,

and

208

Pb/204Pb

ratios

22

. The average

23

. The

(16.936−16.941,

149

2.4 Micro-X-ray fluorescence and diffraction investigation

150

Micro-X-ray fluorescence (µ-XRF) and diffraction (µ-XRD) analyses were used

151

to identify the distribution and speciation of heavy metals in FA, which were glued on

152

the surface of Magic Tape 25. The µ-XRD and µ-XRF measurements were carried out

153

at the BL15U1 beam line of the Shanghai Synchrotron Radiation Facility (SSRF,

154

China). The incident X-ray beam was monochromatized to 18 keV (λ = 0.688 Å) and


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focused to a spot size of 3 µm × 3 µm. Depending on the calibration of a pattern of

156

cerium dioxide, the µ-XRF point spectra and 2D (two-dimensional) µ-XRD patterns

157

were fast-detected at 20 s and 10–20 s, respectively. The µ-XRF point spectra were

158

processed using PyMca 4.3.0 (European Synchrotron Radiation Facility, France)

159

FIT2D software (European Synchrotron Radiation Facility, France) was used to

160

transform 2D patterns into standard 1D diagrams (2θ scan).

161

3. Results and discussion

26

.

162

3.1 Heavy metal contents and Pb isotope ratios in the MSW components

163

To ascertain the contribution of each MSW component to the total heavy metals

164

content, the contents of Pb, copper (Cu), and zinc (Zn) in each component and their

165

proportion relative to the corresponding total metals in the MSW samples were

166

determined, as shown in Figure 2. The MSW samples from three transfer stations

167

were collected to provide the representative ranges of metal contents and Pb isotopic

168

compositions in the MSW components. The difference in Pb contents in each

169

component among the three MSW samples (Figure 2a) was significant (p < 0.05)

170

except for PA, PL, and TE. For example, the Pb contents in GL and RU from MSW1

171

were significantly (p < 0.05) higher than those from MSW2 and MSW3. This

172

variation of heavy metal contents may be attributed not only to the differences in

173

waste matrixes, but also to inter-contamination during waste collection, handling, and

174

transportation

175

contained elevated heavy metals contents compared to those in source separated waste,

176

resulting from the contamination of extrinsic particles having high heavy metal

27

. Zhang et al. reported that the FW components in the mixed MSW


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177

contents 28. The MSW components exhibited a wide range of Pb contents. The lowest

178

average Pb contents, 0.62 ± 0.56 mg/kg, were found in the ME components, and the

179

highest contents, 193 ± 123 mg/kg, were observed in the RU components. In regard to

180

the proportion of Pb in each component (Figure 2d), the contributions of PA and PL to

181

the total Pb in MSW (37.6%−47.9% and 29.8%−32.9%, respectively) were higher

182

than those of the other components. The contribution of FW to Pb in MSW was

183

relatively high (4.7%−16.0%), due to the high proportion of FW in MSW. Besides,

184

although the mass proportion of RU in MSW was low (1.1%−1.5%, as shown in

185

Figure 1), its contribution to the total Pb (5.7%−14.0%) was high because of the high

186

Pb content of this material.

187

Similar to Pb, the contents of Cu and Zn (Figure 2b and 2c, respectively) in most

188

of the components were significantly different (p < 0.05). The highest (77.1 ± 27.9

189

mg/kg) and lowest (1.4 ± 0.4 mg/kg) Cu contents were observed in FW and RU,

190

respectively. The highest and lowest proportions of Cu in MSW were contributed by

191

FW (50.2%−68.8%) and RU (0.02%−0.1%), respectively. The Zn contents in most of

192

the components (all exceeding 100 mg/kg) were higher than Pb and Cu contents. As

193

with Pb, the contribution of RU to Zn in MSW was relatively high (24.6%−34.3%).

194

Thus, RU was one of the main pollution sources of heavy metals in the MSW.

195

To understand the variation and sources of Pb in the MSW components, the 207

Pb/206Pb vs

208

Pb/206Pb for the MSW components, as well as for coal,

196

ratios of

197

metallurgic dust, and paint from Shanghai were compared (Figure 3) 29-31. There was a

198

significant difference (p < 0.05) in Pb isotope ratios among the MSW components,


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Pb/206Pb, and from 2.0740 to 2.1188 for

199

ranging from 0.8478 to 0.8679 for

200

208

201

additives, and possibly extraneous pollutants. Many additives containing specific

202

levels of Pb are added to raw materials during production and the Pb isotopic

203

compositions in those additives have a wide range that could influence the Pb isotope

204

ratios in MSW components. For example, the isotope ratios in paint range from

205

0.5888 ± 0.0029 to 0.8740 ± 0.0025 for

206

2.372 ± 0.0151 for

207

were the lowest (0.8478−0.8529 for

208

(0.8523 ± 0.0028 for

209

raw materials, and the variation of Pb isotope ratios in ME from different MSW may

210

result from the types of metals and additives that the wastes contain. For most MSW

211

components such as GL, PA, PL, and TE, additives from the production process may

212

have had relatively little effect, or the Pb isotopic composition of the additives was

213

similar, as suggested by the similar contents and isotopic data in these components

214

from different MSW. Besides, the difference in the Pb isotope ratios between FW and

215

WO was insignificant (p > 0.05). As mentioned above, the Pb contents in the organic

216

components were influenced mainly by some unidentified pollution sources, so the

217

pollution sources that contributed Pb in FW and WO might be similar. The Pb isotope

218

ratios in FW and WO were within the range of those for coal combustion, indicating

219

that the pollution sources affecting FW and WO might be related or similar to coal

220

combustion 28, 32.

Pb/206Pb. The sources of Pb in MSW components included primary raw materials,

208

207

Pb/206Pb and from 1.3485 ± 0.0103 to

Pb/206Pb.31 As shown in Figure 3, the Pb isotope ratios in ME 207

Pb/206Pb) and close to that of metallurgic dust

207

Pb/206Pb). Thus, Pb in ME appeared to be mainly from the


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221 222

3.2 Influence of air excess ratio on heavy metal contents and Pb isotope ratios in FA

223

The contents of Pb, Cu, and Zn in the FA samples under different ERs are

224

displayed in Figure 4. The ER had a great effect on Pb, Cu, and Zn contents in FA,

225

which ranged from 102 mg/kg to 196 mg/kg, from 635 mg/kg to 2150 mg/kg, and

226

from 744 mg/kg to 1654 mg/kg, respectively. When the thermal reaction occurred

227

under reducing atmosphere (0 < ER < 1), Pb and Zn contents in FA tended to reduce

228

gradually as ER increased from 0.3 to 1.0. Notably, the Zn content in FA at ER = 0.3

229

was more than two times greater than those at ER = 0.7 and 1.0. This suggested that

230

increasing the oxygen amount may inhibit the migration of Pb and Zn in MSW under

231

reducing atmosphere. However, Cu contents did not show a similar trend to Pb and Zn,

232

and ranged greatly from 635 mg/kg to 1504 mg/kg within the ER range 0.3−1.0.

233

Because heavy metals were present in various forms (elemental, sulfides, chlorides,

234

etc.), their migration was influenced by their speciation in each MSW component 21, 33.

235

When the ER was 1.3, the Pb content in FA (exceeding 200 mg/kg) increased almost

236

100% compared to those at ER = 0.3−1.0. Besides, Zn and Cu contents in FA (ER =

237

1.3) were higher than those at ER = 0.5−1.0. This indicated that the oxidizing

238

atmosphere favored the migration of heavy metals such as Pb, Cu, and Zn to fly ash

239

and flue gas. Their chlorides are more stable under higher oxygen condition, as a

240

result, the transformation into metallic chlorides increased their transfer under

241

oxidizing conditions

242

higher than oxides or chlorides, so it can be hardly released under reducing conditions.

21

. For Cu, the boiling point of elemental Cu is significantly


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14

244

MSW, and may change the sources of heavy metals in the thermal treatment fly ashes.

245

The transformation and evaporation of heavy metals during thermal treatment

246

lead to their transfer. The migration of heavy metals differs from metal to metal, as it

247

is affected not only by the thermochemical conditions such as redox atmosphere,

248

temperature, retention time, flue gas composition, mixing conditions etc., but also by

249

the physicochemical properties and distribution of heavy metal compounds in the

250

waste components which influence their evaporation or reaction dynamics kinetics 14,

251

18

In brief, the variation of the ER could influence the migration of heavy metals in

.

252

To understand the sources of Pb in FA from MSW thermal treatment, the Pb

253

isotopic compositions in FA were examined (Figure S2 in the Supporting Information).

254

The variation of Pb isotope ratios in five FA samples was obvious, and ranged from

255

0.8478 to 0.8679 for

256

isotope ratios

257

linear relationship was greatly significant (R2 = 0.89). In the reducing atmosphere, Pb

258

isotope ratios in FA obviously decreased with the increase of the ER from 0.3 to 0.7,

259

suggesting that MSW components with relatively lower Pb isotope ratios significantly

260

influenced Pb isotope ratios in FA. In contrast, as ER increased from 0.7 to 1.3, Pb

261

isotope ratios only slightly increased. The Pb isotope ratios under a low oxygen

262

condition were higher than those under a high oxygen condition, which indicated that

263

the contribution of MSW components containing the relatively higher Pb isotope

264

ratios increased under the low oxygen condition. The change of the ER had an impact

208

208

Pb/206Pb and from 0.8478 to 0.8679 for

Pb/206Pb and

207

207

Pb/206Pb. The

Pb/206Pb exhibited the same trends in FA, and their


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265

on the migration of Pb in different MSW components so as to influence sources of Pb

266

in FA. This observation was supported by the low correlations between

267

ratio and Pb contents in FA (Figure S3 in the Supporting Information).

208

Pb/206Pb

268

The Pb isotope ratios in the FA samples were compared with those in the APCR

269

samples, as shown in Figure 5a. The Pb isotope ratios in APCR ranged from 2.1067 to

270

2.1094 for

271

ratios in APCR (ER = 1.5−2.0) and FA (ER = 0.7, 1.0 and 1.3) were in a narrow range

272

and were far away from those of FA at ER = 0.3 and 0.5. This suggested that sources

273

of Pb in fly ashes under oxidizing conditions were similar, but differed from those

274

under the reducing conditions. The distinction between MSW incineration fly ash

275

samples from different countries was examined by plotting

276

(Figure 5b). The Pb isotope ratios in the MSW incineration ashes obtained from

277

various countries exhibited a significant difference because of differences in the

278

proportion and sources of Pb in MSW components. For example, the 207Pb/206Pb ratio

279

of FA in Shanghai was lower than that in Japan (0.8645 ± 0.0025)

280

(0.8669 ± 0.0027)

281

originally derived Chinese source rocks, which have higher Th/U (206Pb,

282

208

283

respectively) than those in other countries 38.

208

Pb/206Pb, and from 0.8613 to 0.8616 for

208

Pb/206Pb. The Pb isotope

208

12

, and Switzerland (0.8687 ± 0.0008)

Pb are generated from the radioactive decay chain of

Pb/206Pb vs

34, 35

, France

, possibly due to

238

U,

235

3.3 Source identification of Pb in the ash samples

285

To identify major sources of Pb in the APCR and FA samples, the 208

Pb/206Pb

36, 37

284

286

207

207

Pb, and

U, and

207

232

Th

Pb/206Pb vs

Pb/206Pb ratios in these ash samples as well as in the MSW components were


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compared (Figure 6). The isotope ratios in the FA and APCR were mainly bounded

288

by the ratios in the MSW components; furthermore, there was a linear (statistically

289

significant) trend for the Pb isotope ratios in the MSW components and ash samples.

290

The distance between the isotope ratios in MSW components and ash samples enabled

291

the evaluation of the contribution of the MSW components to Pb in the ash samples.

292

Considering the contributions of the components to Pb in MSW discussed above, it

293

can be concluded that FW, PA, PL, and RU were the major sources of Pb in the ash

294

samples.

295

Among Pb isotope ratios in FW, PA, PL, and RU, those for PA and PL were the

296

closest to the isotopic field of APCR (Figure 6a). The ratios for FW and RU were

297

further away from those in APCR than were the ratios of other components.

298

Considering the highest contribution ratios of PA (37.6%−47.9%) and PL

299

(29.8%−32.9%) to Pb in MSW and the high migration ratios of Pb in PA and PL

300

during incineration, PA and PL were identified as the predominant sources of Pb in

301

APCR. Under the oxidizing condition (ER ≥ 1), the isotope ratios of FA were close to

302

those of APCR, as well as of the PA and PL components (Figure 6b), suggesting that

303

there were analogous sources (i.e., PA and PL) for Pb in FA and APCR. In contrast,

304

under a low oxygen content condition, the Pb isotope ratios in FA moved to a higher

305

value as the ER decreased, and this value was higher than that in PL or PA, and close

306

to that of RU. This result suggested that the contribution of the major MSW

307

components to Pb in FA changed significantly and RU surpassed PA as the major

308

source of Pb in FA.


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309

3.4 Migration of Pb during MSW thermal treatment

310

Based on the heavy metal contents and Pb isotope ratios in the ash samples, the

311

migration of Pb during MSW thermal treatment was estimated. As the ER increased

312

from 1.0 to 1.3, the significant increase of Pb, Cu, and Zn contents in FA was due to

313

the promoted migration of heavy metals. This was consistent with previous studies

314

that demonstrated for thermal treatment under oxidizing conditions, more Pb in MSW

315

partitioned into fly ash and flue gas than those under the reducing conditions

316

the other hand, in the present study the major sources of Pb in FA changed relatively

317

little, so this promotion did not result in a great variation of Pb isotope ratios in FA. In

318

comparison with ER=1.0−1.3, as the ER decreased from 1.0 to 0.3, the change of Pb

319

contents was smaller, and suggested that the migration of Pb in MSW was less

320

influenced. Notably, Pb isotope ratios in FA increased significantly, indicating the

321

change in one major source (from PA to RU). It can be hypothesized that as the

322

oxygen content decreased, the migration Pb in RU and PA changed under the reducing

323

atmosphere conditions.

39

. On

324

High levels of Zn and Pb occurred in RU (Figure 2) and a similar trend in the

325

migration of Zn and Pb in RU during thermal treatment was reported previously 40. In

326

the current study, although Pb contents in FA did not increase greatly, the Zn contents

327

in FA at ER = 0.3 and 0.5 were approximately twice and 1.5 times, respectively, those

328

at ER = 0.7. This increase may be because the reducing atmosphere condition

329

promoted the migration of Zn in RU. The correlation between Zn contents and Pb

330

isotope ratios in FA suggested that variations in Zn contents were also caused by the


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major source of Pb. Thus, it is likely that the migration of both Zn and Pb in RU could

332

be promoted simultaneously under the reducing condition as the ER decreased. When

333

the migration of Pb in RU was promoted, the migration of Pb in PA was inhibited.

334

To further ascertain the migration of Pb under different atmosphere conditions,

335

the µ-XRF maps of Pb and Zn obtained from the FA samples at ER = 0.3 and 1.3 were

336

evaluated (Figure S4). It was apparent that Pb and Zn in the two FA samples exhibited

337

similar distributions and strong correlations, as previously reported by Zhu et al.,

338

indicating that during the thermal treatment process, Pb migration was associated with

339

Zn 25. In the present study, the correlation between Zn and Pb in FA at ER = 0.3 was

340

higher than that at ER = 1.3, which may be attributed to the fact that the migration of

341

Pb and Zn under the reducing condition was influenced more by RU than was

342

migration under the oxidizing condition, an explanation supported by the results of Pb

343

source identification in FA. Moreover, the compounds of Pb and Zn were identified

344

from µ-XRD patterns in the FA samples at ER = 0.3 as PbCl2O4, PbS2, ZnMn3O7,

345

Ti3Zn3O0.5 and at ER = 1.3 as ZnCl2, CaPbO3. The Zn and Pb that were associated

346

with some heavy metals were mainly in the form of mixed metal oxides. The

347

chemical combination of Pb and Zn was not detected by µ-XRD, indicating their

348

coexistence in solid solutions or as amorphous forms. It is noteworthy that when the

349

oxygen content was reduced, metal sulfide was observed in FA (ER = 0.3), which may

350

be attributed to the higher level of sulfur in RU 41. Therefore, RU was a predominant

351

contributor to Pb in FA under the low oxygen condition.

352

4. Conclusions


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353

Overall, because different MSW components have distinct Pb isotopic

354

ﬁngerprints, it is possible to use the Pb isotopic approach to trace sources and

355

understand the migration of Pb during the MSW thermal treatment. The µ-XRD and

356

µ-XRF analyses with high-energy light source and precise microscopy, could provide

357

the spatial distribution and speciation information of metals in micro-scales. By

358

combining Pb isotope ratios with µ-XRD and µ-XRF analyses, the predominant

359

sources of Pb in the FA samples under different atmosphere conditions could be

360

identified and the variations of Pb migration from different MSW components to FA

361

could be revealed. Thus, the Pb isotopic approach was very useful for gaining a better

362

understanding of the migration behavior of Pb during the high temperature process.

363

Future Pb monitoring programs could use this tool to trace Pb release during different

364

waste treatment and disposal processes, and provide a scientific basis on which to

365

implement more targeted and appropriate control strategies.

366 367

Acknowledgments

368

This study was financially supported by the National Natural Science Foundation of

369

China (No. 21577102), the National Social Science Fund of China (No.12&ZD236),

370

and the Fundamental Research Funds for the Central Universities.

371 372

Supporting Information

373

The Supporting Information is available free of charge on the ACS Publications website at DOI:

374

10.1021/acs.energyfuels.7b03387.

375

Table S1 Ultimate and proximate analysis of the MSW1 sample; Figure S1 Schematic diagram of


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the thermal treatment apparatus; Figure S2 Effect of air excess ratio on 208Pb/206Pb and 207Pb/206Pb

377

ratios in the fly ash; Figure S3 The correlation of lead contents and 207Pb/206Pb ratios in the fly ash;

378

Figure S4 The µ-XRF images of lead and zinc in the fly ash samples.

379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414

References 1. Callender, E. Treatise on Geochemistry 2003, 9, 67–105. 2. Mu, L.; Peng, L.; Liu, X.; Bai, H.; Song, C.; Wang, Y.; Li, Z. Environ. Sci. Technol. 2012, 46, 6425–6430. 3. Morf, L. S.; Brunner, P. H.; Spaun, S. Waste Manage. Res. 2000, 18, 4–15. 4. Lu, S.; Du, Y.; Zhong, D.; Zhao, B.; Li, X.; Xu, M.; Li, Z.; Luo, Y.; Yan, J.; Wu, L. Environ. Sci. Technol. 2012, 46, 5025–5031. 5. Nowak, B.; Rocha, S. F.; Aschenbrenner, P.; Rechberger, H.; Winter, F. Chem. Eng. J. 2012, 179, 178–185. 6. Vogel, C.; Adam, C. Environ. Sci. Technol. 2011, 45, 7445–7450. 7. Shiel, A. E.; Weis, D.; Orians, K. J. Sci. Total Environ. 2010, 408, 2357–2368. 8. Wiederhold, J. G. Environ. Sci. Technol. 2015, 49, 2606–2624. 9. Ochoa, G. R.; Weiss, D. J. Environ. Sci. Technol. 2015, 49, 12560–12567. 10. Jamiesonhanes, J. H.; Amos, R. T.; Blowes, D. W. Environ. Sci. Technol. 2012, 46, 13311– 13316. 11. Wang, X.; Luo, J.; Yin, R.; Yuan, W.; Lin, C. J.; Sommar, J.; Feng, X.; Wang, H.; Lin, C. Environ. Sci. Technol. 2016, 51, 801–809. 12. Dewana, N.; Majestica, B. J.; Kettererb, M. E.; Miller-Schulzec, J. P.; Shaferd, M. M.; Schauerd, J. J.; Solomonf, P. A.; Artamonovag, M.; Chenh, B. B. Atmos. Environ. 2015, 120, 438–446. 13. Sun, G. X.; Wang, X. J.; Hu, Q. H. Environ. Pollut. 2011, 159, 3406–3410. 14. Zhang, H.; Yao, Q. S.; Zhu, Y. M.; Fan, S. S.; He, P. J. Chinese Sci. Bull. 2013, 58, 162–168. 15. Gallon, C.; Ranville, M. A.; Conaway, C. H.; Landing, W. M.; Buck, C. S.; Morton, P. L.; Flegal, A. R. Environ. Sci. Technol. 2011, 45, 9874–9882. 16. Li, H. B.; Cui, X. Y.; Li, K.; Li, J.; Juhasz, A. L.; Ma, L. Q. Environ. Sci. Technol. 2014, 48, 8548−8555. 17. Dang, D. H.; Schäfer, J.; Brach-Papa, C.; Lenoble, V.; Durrieu, G.; Dutruch, L.; Chiffoleau, J. F.; Gonzalez, J. L.; Blanc, G.; Mullot, J. U.; Mounier, S.; Garnier, C. Environ. Sci. Technol. 2015, 49, 11438−11448. 18. Carignan, J.; Libourel, G.; Cloquet, C.; Le, F. L. Environ. Sci. Technol. 2005, 39, 2018–2024. 19. Wu, M. H.; Lin, C. L.; Zeng, W. Y. Fuel Process. Technol. 2014, 125, 67–72. 20. Dong, J.; Chi, Y.; Tang, Y.; Ni, M.; Nzihou, A.; Weisshortala, E.; Huang, Q. Energ. Fuel. 2016, 30, 3994–4001. 21. Chiang, K. Y.; Wang, K. S.; Lin, F. L.; Chu, W. T. Sci. Total Environ. 1997, 203, 129–140.


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

415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451

22. Yu, J.; Sun, L.; Xiang, J.; Hu, S.; Su, S.; Qiu, J. Chemosphere 2012, 86, 1122–1126. 23. Liu, Y. S.; Liu, Y. S. Environ. Sci. Technol. 2005, 39, 3855–3863. 24. Belevi, H.; Moench, H. Environ. Sci. Technol. 2000, 34, 2501–2506. 25. Li, Y.; Zhang, H.; Shao, L. M.; He, P. J. J. Hazard. Mater. 2017, 327, 28–34. 26. Zhang, H.; He, P. J.; Shao, L. M. Environ. Sci. Technol. 2008, 42, 6211–6217. 27. Abanades, S.; Flamant, G.; Gagnepain, B.; Gauthier, D. Waste Manage. Res. 2002, 20, 55– 68. 28. Strelow, F. W. E. Anal. Chem. 1978, 50, 1359–1361. 29. Rehkämper, M.; Mezger, K. 2000, 15, 1451–1460. 30. Zhao, Z. Q.; Zhang, W.; Li, X. D.; Yang, Z.; Zheng, H. Y.; Ding, H.; Wang, Q. L.; Xiao, J.; Fu, P. Q. Atmos. Environ. 2015, 115, 163–169. 31. Zhu, Y. M.; Zhang, H.; Fan, S. S.; Wang, S. J.; Xia, Y.; Shao, L. M.; He, P. J. J. Hazard. Mater. 2014, 276, 241–252. 32. Solé, V. A.; Papillon, E.; Cotte, M.; Walter, P.; Susini, J. Spectrochim. Acta B 2007, 62, 63– 68. 33. Hasselriis, F.; Licata, A. J. Hazard. Mater. 1995, 47, 77–102. 34. Zhang, H.; He, P. J.; Shao, L. M.; Lee, D. J. Environ. Sci. Technol. 2008, 42, 1586–1593. 35. Tan, M. G.; Zhang, G. L.; Li, X. L.; Zhang, Y. X.; Yue, W. S.; Chen, J. M.; Wang, Y. S.; Li, A. G.; Li, Y.; Zhang, Y. M. Anal. Chem. 2006, 78, 8044–8050. 36. Chen, J.; Tan, M. Y.; Zhang, Y.; Lu, W.; Tong, Y.; Zhang, G.; Li, Y. Atmos. Environ. 2005, 39, 1245–1253. 37. Feng, L.; Zhang, G. L.; Tan, M. G.; Yan, C. H.; Li, X. L.; Li, Y. L.; Yan, L.; Zhang, Y. M.; Shan, Z. Environ. Sci. Technol. 2010, 44, 4760–4765. 38. Li, F. L.; Liu, C. Q.; Yang, Y. G.; Bi, X. Y.; Liu, T. Z.; Zhao, Z. Q. Sci. Total Environ. 2012, 431, 339–347. 39. Okada, T.; Matsuto, T. Chemosphere 2009, 75, 272–277. 40. Sakata, M.; Kurata, M.; Tanaka, N. Geochem. J. 2008, 34, 23–32. 41. Mukai, H.; Furuta, N.; Fujii, T.; Ambe, Y.; Sakamoto, K.; Hashimoto, Y. Environ. Sci. Technol. 1993, 27, 1347–1356. 42. Chiaradia, M.; Cupelin, F. Atmos. Environ. 2000, 34, 959–971. 43. Hansmann, W.; Köppel, V. Chem. Geol. 2000, 171, 123–144. 44. Ewing, S. A.; Christensen, J. N.; Brown, S. T.; Vancuren, R. A.; Cliff, S. S.; Depaolo, D. J. Environ. Sci. Technol. 2010, 44, 8911–8916. 45. Dong, J.; Chi, Y.; Tang, Y.; Ni, M.; Nzihou, A.; Weisshortala, E.; Huang, Q. Energ. Fuel. 2015, 29, 7516–7525. 46. Borrok, D. M.; Gieré, R.; Ren, M.; Landa, E. R. Environ. Sci. Technol. 2010, 44, 9219–9224. 47. Tang, Y. T.; Ma, X. Q.; Zhang, C.; Yu, Q. H.; Fan, Y. Fuel 2016, 165, 272–278.

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List of Figure Captions

455

Figure 1 The physical compositions of the three municipal solid waste samples on a


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wet basis.

457

Figure 2 Contents of (a) lead (Pb), (b) copper (Cu), and (c) zinc (Zn), and (d) their

458

proportions in the municipal solid waste (MSW) components.

459

Figure 3 Lead (Pb) isotopic compositions (208Pb/206Pb vs 207Pb/206Pb) in the

460

municipal solid waste (MSW) components (this study) and the reported samples,

461

including coal, paint, and metallurgical dust, as well as the Pb growth curve, which

462

were obtained from references 29-31.

463

Figure 4 Contents of (a) lead (Pb), (b) zinc (Zn), and (c) copper (Cu) in the fly ash

464

(FA) arising from combustion at various air excess ratios (ERs).

465

Figure 5 Lead isotope ratios 208Pb/206Pb vs 207Pb/206Pb in the fly ash (FA) and air

466

pollution control residue (APCR) samples in (a) this study, and (b) as reported for

467

municipal solid waste (MSW) combustion ash samples from Shanghai, Japan, France,

468

and Switzerland 12, 34-37.

469

Figure 6 Lead isotope ratios 208Pb/206Pb vs 207Pb/206Pb (a) in municipal solid waste

470

(MSW) components, air pollution control residue (APCR) and fly ash (FA) samples

471

with the lead growth curve, and (b) in some MSW1 components and the FA samples.

472 473 474 475 476 477 478 479 480


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

481 482 483 484 485 486 487

488 489 490 491 492 493 494 495 496

Figure 1 The physical compositions of the three municipal solid waste samples on a wet basis.

497 498 499 500 501 502 503


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504 505 506 507 508 509 510 511 512 513 1

514 515 516 517 518

Figure 2 Contents of (a) lead (Pb), (b) copper (Cu), and (c) zinc (Zn), and (d) their

519

proportions in the municipal solid waste (MSW) components.

520 521 522 523 524 525


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

526 527 528 529 530 531

532 533

Figure 3 Lead (Pb) isotopic compositions (208Pb/206Pb vs 207Pb/206Pb) in the

534

municipal solid waste (MSW) components (this study) and the reported samples,

535

including coal, paint, and metallurgical dust, as well as the Pb growth curve, which

536

were obtained from the literatures 29-31.

537 538 539 540 541


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Energy & Fuels

542 543 544 545 546 547 548

549 550

Figure 4 Contents of (a) lead (Pb), (b) zinc (Zn), and (c) copper (Cu) in the fly ash

551

(FA) arising from combustion at various air excess ratios (ERs).

552 553 554 555 556 557


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558 559 560 561 562

563 564

Figure 5 Lead isotope ratios 208Pb/206Pb vs 207Pb/206Pb in the fly ash (FA) and air

565

pollution control residue (APCR) samples in (a) this study, and (b) as reported for

566

municipal solid waste (MSW) combustion ash samples from Shanghai, Japan, France,

567

and Switzerland 12, 34-37.

568 569 570 571 572 573 574


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Energy & Fuels

575 576 577 578 579

580 581

Figure 6 Lead isotope ratios 208Pb/206Pb vs 207Pb/206Pb (a) in municipal solid waste

582

(MSW) components from three MSW transfer stations, air pollution control residue

583

(APCR) and fly ash (FA) samples with the lead growth curve, and (b) in some MSW1

584

components and the FA samples.

585


Using Lead Isotopes To Assess Source and Migration of Lead during

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