Management of Electronic Waste E-Book
177,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
MANAGEMENT OF ELECTRONIC WASTE Holistic view of the current and future trends in electronic waste management, focusing on recycling, technologies, and regulations Management of Electronic Waste delivers a complete overview of all aspects related to the toxicity characterization of electronic wastes, along with other important topics including resource recovery, recycling strategies, biotechnological advancements, and current perspectives on waste generation and management. The book presents hazards associated with conventional recycling methods and highlights environmentally compatible economic approaches for resource recovery, along with eco-friendly strategies for management of electronic wastes. The high metallic content, heterogeneous and composite nature of e-wastes make them a rich secondary reservoir of metals. The book explores the valuable potential of e-waste and highlights the eco-friendly, sustainable technologies and recycling strategies for the profitable and effective conversion of waste to wealth. Written by a highly qualified and internationally renowned author, Management of Electronic Waste covers sample topics such as: * Rise of e-waste generation paired with rising economies and mounting demand for electrical and electronic devices, with a country-by-country breakdown * Status of e-waste management and recycling efforts around the world, along with key processes that drive e-waste recycling * Macroeconomic trends between global demand and supply for metal resources and the transition of linear to circular economy * Bioleaching, an economic and green approach for recovery of metals, from e-waste and other low grade metal repositories * Different metallurgical approaches for extraction and recovery of resources from e-waste and their pros and cons Filling a gap on the understudied biotechnological recycling techniques and methods for mitigating environmental pollution caused by electronic waste, Management of Electronic Waste serves as an excellent guide on the subject for electronic waste producers, consumers, recycling industries, policy and law makers, academicians, and researchers.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 880
Veröffentlichungsjahr: 2023
Ähnliche
Table of Contents
Cover
Table of Contents
Title Page
Copyright
Dedication
List of Contributors
Preface
Acknowledgment
1 An Introduction to Electronic Waste
1.1 Introduction
1.2 Generation and Composition of E-Waste
1.3 Present Status of E-Waste Management and Recycling
1.4 Comparative Assessment of the Metallurgical Options for Metal Recovery
1.5 Future Prospects
1.6 Conclusion
References
2 The Global Challenge of E-Waste Generation
2.1 Introduction
2.2 The Fate of Steel and Al Alloys
2.3 The Fate of Synthetic Polymers
2.4 The Fate of Glass Present in E-Waste
2.5 The Fate of Geochemically Scarce Elements in Electric and Electronic Components of E-Waste
2.6 What Happens to Other Significant Constituents of E-Waste?
2.7 Conclusion: The Global Challenge of E-Waste
References
3 Generation, Composition, Collection, and Treatment of E-Waste
Abbreviations
3.1 Introduction
3.2 Global E-Waste Generation Scenario
3.3 General Composition of E-Waste
3.4 E-Waste Collection Strategies
3.5 Formal E-Waste Management
3.6 Informal E-Waste Management
3.7 Treatment of E-Waste
3.8 Reuse and Refurbish
3.9 Recycle
3.10 Recovery
3.11 Reduce
3.12 Rethinking
3.13 Conclusion
References
4 Toxicity Characterization and Environmental Impact of E-Waste Processing
4.1 Introduction
4.2 Impact of E-Waste
4.3 Environmental Impact
4.4 Health Impact
4.5 Ecological Impact
4.6 Impact from Processing E-Waste
4.7 Conclusions
References
5 Exposure to E-Wastes and Health Risk Assessment
5.1 Introduction
5.2 E-Waste Categorization and Vulnerable Population
5.3 Exposure Pathways and Health Implications of E-Waste
5.4 Chemical Composition of E-Waste and Health Risks Associated with Their Exposure
5.5 Health Risk Assessments
5.6 E-Waste Management
5.7 Conclusion
References
6 Metal Resources in Electronics: Trends, Opportunities and Challenges
6.1 Introduction
6.2 Composition of Different EEE Components: Past, Present, and Tendencies
6.3 Environmental Burden of the Electronic Devices
6.4 Recycling and Metal Recovery
6.5 Major Challenges in Management
6.6 Concluding Remarks and Perspectives
References
7 Urban Mining of e-Waste: Conversion of Waste to Wealth
7.1 The Principles of Urban Mining and the Life Cycle of Electrical and Electronic Equipment
7.2 Materials for Recovery from Electrical and Electronic Equipment
7.3 The Collections and Social Attitude Toward Disposal of E-Waste
7.4 Discussion and Conclusion
References
8 Life Cycle Assessment and Techno-Economic of E-waste Recycling
8.1 Introduction
8.2 Life Cycle Assessment of E-waste Systems
8.3 Techno-Economic Analysis
8.4 Conclusion
References
9 E-waste Recycling: Transition from Linear to Circular Economy
9.1 Introduction
9.2 Linear Economy and its Limitations
9.3 Circular Economy – Need of the Hour
9.4 The Transition from Linear to Circular Economy
9.5 Understanding E-Waste Through Smartphones
9.6 Conclusion
References
10 E-Waste Valorization and Resource Recovery
10.1 Introduction
10.2 E-Waste Composition
10.3 Resource Recovery Techniques
10.4 Valorization of E-Waste for Circular Economy
10.5 Opportunities and Challenges of Valorization of E-Waste
10.6 Conclusion
References
11 Hydrometallurgical Processing of E-waste and Metal Recovery
11.1 Introduction
11.2 Characterization
11.3 Leaching Techniques
11.4 Separation and Recovery
11.5 Emerging Technologies for E-Waste Recycling
11.6 Conclusion and Futures Perspectives
Acknowledgments
References
12 Microbiology Behind Biological Metal Extraction
12.1 Background
12.2 Overview of E-Waste: A Global Hazard
12.3 E-Waste Categories and Classification
12.4 Environmental Hazards Due to E-Waste Composition
12.5 Health Risks from E-Waste Exposure
12.6 Bioremediation Techniques for E-Waste Management
12.7 Why Biological Methods for Metal Extraction from E-Waste
12.8 Types of Bioremediation
12.9 Factors Influencing Microbial Metal Leaching
12.10 Conclusion
12.11 Future Prospects
References
13 Advances in Bioleaching of Rare Earth Elements from Electronic Wastes
13.1 Introduction
13.2 REEs Recovery Technology
13.3 Post-Leaching/Bioleaching Process
13.4 Conclusion and Outlook
References
14 Bioprocessing of E-waste for Metal Recovery
14.1 Introduction
14.2 Bioprocessing of E-waste for Metal Recovery
14.3 Biosorption and Bioaccumulation of Metals
14.4 Perspective and Future Aspects
Acknowledgments
References
15 State-of-the-Art Biotechnological Recycling Processes
15.1 Introduction
15.2 State-of-the-art Biotechnological Processes
15.3 Conclusion and Future Perspectives
References
16 Biorecovery of Critical and Precious Metals
16.1 Introduction to Critical and Precious Metals for Recovery
16.2 Precious Metal E-waste Recovery in the International Market
16.3 E-waste Sources and Progression
16.4 Conventional E-waste Metal Recovery Methods and Their Limitations
16.5 Biorecovery of Valuable Metals from Electronic Waste
16.6 Factors Affecting Biorecovery of Precious Metals
16.7 Confirmatory Tests for Recovered Metals from E-waste
16.8 Biorecovery and Environment Sustainability
16.9 Biorecovery and Socio-economic Sustainability
16.10 Conclusion
References
17 Biohydrometallurgical Metal Recycling/Recovery from E-waste: Current Trend, Challenges, and Future Perspective
17.1 Introduction
17.2 Overview of Biological Approach for Recycling of Metals
17.3 Existing E-waste Management Challenges
17.4 Advance Technology for Recycling Metals
17.5 Future Development Strategies for E-waste Management
17.6 Conclusion and Recommendation
References
Index
End User License Agreement
List of Tables
Chapter 1
Table. 1.1 E-waste generation for the major economies of the world for the y...
Chapter 2
Table. 2.1 Relatively recently developed synthetic polymers are emerging in ...
Table. 2.2 Geochemically scarce elements that may be functional, or dysfunct...
Table. 2.3 Estimated losses (as % of input) of geochemically scarce function...
Table. 2.4 Reported geochemically scarce elements produced by plants co-proc...
Table. 2.5 Estimated current recoveries (in % of the amount present in e-was...
Chapter 3
Table. 3.1 Fates of different e-waste components after utilization.
Chapter 4
Table. 4.1 Environmental impact of common substances present in e-waste.
Table. 4.2 Health impact of common substances found in e-waste.
Chapter 5
Table. 5.1 Routes of exposure to various chemical components of e-waste and ...
Table. 5.2 Noncarcinogenic and carcinogenic risk assessment scales.
Chapter 6
Table. 6.1 Metallic composition of PCBs found by different authors in a peri...
Table. 6.2 Composition differences for different types of PCBs
Table. 6.3 Mass fraction of LED lamps' macro components over time.
Table. 6.4 Composition of waste white LEDs
Table. 6.5 Composition of screens according to different authors
Table. 6.6 Permanent magnets' characteristics relevant for applications
Chapter 7
Table. 7.1 Comparing primary energy required for the extraction of materials...
Table. 7.2 Brief characteristics of the main materials in manufacturing elec...
Chapter 8
Table. 8.1 Real-time LCA application on various E-waste management strategie...
Table. 8.2 Details of environmental LCA of different technologies.
Chapter 9
Table. 9.1 Types of industrial economies.
Table. 9.2 Environmental, social, and economic benefits of CE.
Table. 9.3 Eco-innovations for implementation of CE.
Chapter 10
Table. 10.1 Material composition of different types of WEEE.
Table. 10.2 The summary of value-added products prepared using different par...
Table. 10.3 Top leading companies working in the global e-waste management a...
Chapter 11
Table. 11.1 Literature review of the chemical composition of the main elemen...
Table. 11.2 Literature review of the alkaline leaching of e-waste.
Table. 11.3 Examples of chemical groups and formulas of cationic and anionic...
Table. 11.4 Examples of chemical groups and formulas of chelating resins (In...
Table. 11.5 Properties of ILs.
Table. 11.6 Different types of DESs and their general formulas reproduced (S...
Table. 11.7 Physicochemical and thermal properties of DES (Padwal et al. 202...
Chapter 12
Table. 12.1 E-waste sources, components, and their hazardous effect on the e...
Table. 12.2 Detoxifying strategies for different metals adopted by metal-tol...
Table. 12.3 Microorganisms used for heavy metal remediation from e-waste (Pu...
Chapter 13
Table. 13.1 Distribution and production of rare earth oxides worldwide.
Table. 13.2 Types of microorganisms applied to rare earth element extraction...
Table. 13.3 Efficiency of bioleaching precious metals using cyanogen-produci...
Table. 13.4 A summary of studies using MFC for recovery of metals from solut...
Chapter 14
Table. 14.1 Recent investigations on bioprocessing of metal recovery from e-...
Chapter 15
Table. 15.1 Biosorption capacity of different biomasses for precious metals ...
Table. 15.2 Stability constant of metal and siderophore complexes.
Chapter 16
Table. 16.1 Microorganisms used for bioleaching of precious metals.
Chapter 17
Table. 17.1 Metals content (% and ppm values) in different e-wastes.
Table. 17.2 Microorganisms and optimum conditions applied for the solubiliza...
Table. 17.3 Organisms and percent metal leaching from e-waste.
List of Illustrations
Chapter 1
Figure 1.1 Benefits of e-waste recycling.
Figure 1.2 Generalized steps involved in pyrometallurgical recovery of metal...
Figure 1.3 Schematic representation of hydrometallurgical recovery of metals...
Figure 1.4 Schematic representation of biohydrometallurgical recovery of met...
Chapter 3
Figure 3.1 Flow diagram of a general WEEE management system (Masud et al. 20...
Figure 3.2 E-waste generation scenario in (a) Asia region, (b) Europe region...
Figure 3.3 Health hazards and risks associated with electronic waste (Jaibee...
Figure 3.4 Environmental impacts of e-waste (Dopp & Rettenmeier, 2013; Masud...
Figure 3.5 Global e-waste management strategies (Borthakur & Govind, 2017; L...
Figure 3.6 Formal E-waste process (Strike, 2021; WA, 2021).
Figure 3.7 Flow process of EPR policy.
Figure 3.8 Flow diagram of a take-back policy.
Figure 3.9 Informal E-waste Process (Barker, 2020; Record, 2019; Starr, 2019...
Figure 3.10 Illustrates the intricate interdependencies between reuse barrie...
Figure 3.11 Recycling of e-waste and recovery of valuable materials.
Figure 3.12 A simplified flowchart of the electronic goods recycling process...
Figure 3.13 A simplified diagram of the process steps at a material recovery...
Figure 3.14 Four ways to reduce e-waste carbon footprint.
Chapter 4
Figure 4.1 E-waste processing.
Chapter 5
Figure 5.1 Composition of e-waste.
Figure 5.2 Global e-waste production.
Figure 5.3 Exposure pathways of e-waste.
Chapter 6
Figure 6.1 Evolution of PCBs over the years.
Figure 6.2 Design variability of LED lamps (a) and typical components (b)....
Figure 6.3 Screen design evolution. (a) CRT display design.(b) PDP displ...
Figure 6.4 Timeline of battery evolution.
Figure 6.5 Elemental composition variation (wt.-%) of PM in accordance with ...
Chapter 7
Figure 7.1 Urban mining tasks in the circular economy.
Figure 7.2 Environmental impact costs in the life cycle of electrical and el...
Figure 7.3 Average material content in six categories of household e-waste....
Figure 7.4 Fate of end of life electrical and electronic equipment – Decisio...
Chapter 8
Figure 8.1 Elements of techno-economic model.
Figure 8.2 Model of the costs and revenues in an MRP (metal recovery process...
Figure 8.3 Stages of the LCA.
Figure 8.4 A general illustration of system boundaries of all the model scen...
Chapter 9
Figure 9.1 Linear and circular economies.
Chapter 10
Figure 10.1 Typical composition of e-waste and WPCBs.
Figure 10.2 Individual sub-processes involved in the pre-treatment of e-wast...
Figure 10.3 A circular economy approach toward e-waste management and valori...
Figure 10.4 Schematic representation of steps followed to recover metallic f...
Chapter 11
Figure 11.1 Hydrometallurgical process flowsheet.
Figure 11.2 Pourbaix equilibrium potential–pH Diagram of (A) Au and (B) Ag p...
Figure 11.3 Structure of Au-thiosulfate complex, adapted from (Zhao et al. (...
Figure 11.4 Example of chemical structures of common organic extractants use...
Figure 11.5 Example of chelating reaction between the resin (iminodiacetate)...
Figure 11.6 Schematic of extraction process via ILs, adapted from reference....
Figure 11.7 Schematic representation of leaching of LiCoO
2
using ChCl:citric...
Chapter 12
Figure 12.1 Different strategies for heavy metal extraction from e-waste.
Figure 12.2 Types of bioremediation techniques and mechanisms.
Figure 12.3 Different Metal detoxification strategies adopted by metal-toler...
Chapter 13
Figure 13.1 The distribution of rare earth consumption in China in 2022 and ...
Figure 13.2 Schematic diagram of metal (M) leaching mechanism of
A. ferrooxi
...
Figure 13.3 Various post-leaching metal recovery methods.
Figure 13.4 An integrated process for vanadium purification from burnt oil a...
Figure 13.5 A process using solvent extraction (SX) for recovering REEs from...
Figure 13.6 An example of ion exchange with a copper ion.
Figure 13.7 A flowsheet for recovering REEs, Ga, and Al from fly ash using a...
Figure 13.8 Illustration of MFC for wastewater treatment in the anode chambe...
Chapter 14
Figure 14.1 Bioleaching mechanism
Chapter 15
Figure 15.1 Comparison of different processes for metal recovery.
Figure 15.2 Illustration of a peptide-functionalized column for the selectiv...
Chapter 16
Figure 16.1 Recapturing of metals using chemical method.
Figure 16.2 Recycling methods.
Figure 16.3 Treatment process – steps.
Figure 16.4 Recapturing of gold by the photocatalytic method based on TiO
2
/S...
Figure 16.5 Summary of the process of pyrometallurgy in recovery from e-wast...
Figure 16.6 Types of bioleaching processes.
Figure 16.7 Metal sulfides dissolution using (A) thiosulfate and (B) polysul...
Figure 16.8 Direct and Indirect mechanisms of bioleaching.
Figure 16.9 Types of metal mobilization mechanisms.
Chapter 17
Figure 17.1 Contact and noncontact bioleaching mechanisms.
Figure 17.2 Application of bioinformatics for biohydrometallurgy.
Guide
Cover
Table of Contents
Title Page
Copyright
Dedication
List of Contributors
Preface
Acknowledgment
Begin Reading
Index
End User License Agreement
Pages
iii
iv
v
xvii
xviii
xix
xx
xxi
xxii
xxiii
xxiv
xxv
xxvii
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
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
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
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
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
Management of Electronic Waste
Resource Recovery, Technology and Regulation
Edited byAnshu PriyaCity University of Hong Kong, Kowloon, Hong Kong
Copyright © 2024 by John Wiley & Sons Inc All rights reserved.
Published by John Wiley & Sons, Inc., Hoboken, New Jersey.Published simultaneously in Canada.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permission.
Trademarks: Wiley and the Wiley logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates in the United States and other countries and may not be used without written permission. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book.
Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.
For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at www.wiley.com.
Library of Congress Cataloging-in-Publication Data
Names: Priya, Anshu, editor.Title: Management of electronic waste : resource recovery, technology and regulation / edited by Anshu Priya.Description: Hoboken, New Jersey : Wiley, [2024] | Includes index.Identifiers: LCCN 2023046576 (print) | LCCN 2023046577 (ebook) | ISBN 9781119894339 (cloth) | ISBN 9781119894346 (adobe pdf) | ISBN 9781119894353 (epub)Subjects: LCSH: Electronic waste–Management.Classification: LCC TD799.85 .M36 2024 (print) | LCC TD799.85 (ebook) | DDC 621.3815028/6–dc23/eng/20231102LC record available at https://lccn.loc.gov/2023046576LC ebook record available at https://lccn.loc.gov/2023046577
Cover image(s): WileyCover design: © liangpv/Getty Images
Dedicated to my dearest grandfather, Mr. Anand Swaroop Varma, for his countless blessings, immense love, and endless support. You are a great source of encouragement to me. Thank you for inspiring me always. I owe it all to you...
List of Contributors
Abhinav Ashesh
KPMG India
Gurgaon
Haryana
India
Mishra Bhawana
Department of Environmental Sciences
Central University of Himachal Pradesh (CUHP)
Shahpur
Dharamshala
Kangra
Himachal Pradesh
India
Amilton Barbosa Botelho Junior
Department of Chemical Engineering
Polytechnic School
University of Sao Paulo
Sao Paulo
Brazil
Marcelo P. Cenci
Materials Engineering Department
Federal University of Rio Grande do Sul
Porto Alegre/RS
Brazil
Mital Chakankar
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Venkata Ravi Sankar Cheela
Civil Engineering Department
MVGR College of Engineering (A)
Vizianagaram
Andhra Pradesh
India
Pranav Prashant Dagwar
Department of Environmental Science and Engineering
SRM University-AP
Amaravati
Andhra Pradesh
India
and
CSIR-National Environmental Engineering Research Institute (CSIR-NEERI)
Nagpur
Maharashtra
India
Shailesh R. Dave
Xavier Research Foundation
Loyola Centre for Research and Development
St. Xavier's College Campus
Ahmedabad
India
Pant Deepak
Department of Environmental Sciences
Central University of Himachal Pradesh (CUHP)
Shahpur, Dharamshala, Kangra
Himachal Pradesh
India
Deblina Dutta
Department of Environmental Science and Engineering
SRM University-AP
Amaravati
Andhra Pradesh
India
Tingyue Gu
Department of Chemical and Biomolecular Engineering
Institute for Sustainable Energy and the Environment
Ohio University
Athens
OH
USA
Subrata Hait
Department of Civil and Environmental Engineering
Indian Institute of Technology Patna
Patna
Bihar
India
Pg Rusydina Idris
Civil Engineering Programme Area
Universiti Teknologi Brunei
Gadong
Brunei Darussalam
Kaviul Islam
Department of Mechanical Engineering
Iowa State University
Ames
IA
USA
and
School of Science and Engineering
Canadian University of Bangladesh
Dhaka
Bangladesh
Rohan Jain
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Sharifa Khatun
Department of Mechanical Engineering
Rajshahi University of Engineering and Technology
Rajshahi
Bangladesh
Atul Kumar
Department of Veterinary Public Health and Epidemiology
CSK HP Agricultural University
Palampur
Himachal Pradesh
India
Sunil Kumar
CSIR-National Environmental Engineering Research Institute (CSIR-NEERI)
Nagpur
Maharashtra
India
Sabine Kutschke
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Franziska Lederer
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Mahadi Hasan Masud
Mechanical & Automotive Discipline
School of Engineering
RMIT University, Bundoora Campus
Melbourne
VIC
Australia
and
Department of Mechanical Engineering
Rajshahi University of Engineering and Technology
Rajshahi
Bangladesh
Nahid Imtiaz Masuk
Department of Mechanical Engineering
Rajshahi University of Engineering and Technology
Rajshahi
Bangladesh
Shivangi Mathur
Department of Biotechnology
President Science College
Gujarat University
Ahmedabad
Gujarat
India
Sabine Matys
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Pankaj Meena
CSIR-National Environmental Engineering Research Institute (CSIR-NEERI)
Nagpur
Maharashtra
India
Soumya V. Menon
Department of Chemistry and Biochemistry
School of Sciences
Jain (Deemed to be) University
Bengaluru
Karnataka
India
José C. Mengue Model
Materials Engineering Department
Federal University of Rio Grande do Sul
Porto Alegre/RS
Brazil
Monjur Mourshed
Mechanical & Automotive Discipline
School of Engineering
RMIT University, Bundoora Campus
Melbourne
VIC
Australia
and
Department of Mechanical Engineering
Rajshahi University of Engineering and Technology
Rajshahi
Bangladesh
Seyyed Mohammad Mousavi
Biotechnology Group
Chemical Engineering Department
Tarbiat Modares University
Tehran
Iran
and
Modares Environmental Research Institute
Tarbiat Modares University
Tehran
Iran
Daniel D. Munchen
Materials Engineering Department
Federal University of Rio Grande do Sul
Porto Alegre/RS
Brazil
Ashkan Namdar
Faculty of Materials Science and Engineering
Khajeh Nasir Toosi University of Technology
Tehran
Iran
Tannaz Naseri
Biotechnology Group
Chemical Engineering Department
Tarbiat Modares University
Tehran
Iran
Piotr Nowakowski
Silesian University of Technology
Faculty of Transport and Aviation Engineering
Katowice
Poland
Biswaranjan Paital
Redox Regulation Laboratory
Department of Zoology
Odisha University of Agriculture and Technology
Bhubaneswar
Odisha
India
Katrin Pollmann
Department of Biotechnology
Helmholtz Institute Freiberg for Resource Technology
Helmholtz-Zentrum Dresden-Rossendorf
Dresden
Germany
Anshu Priya
School of Energy and Environment
City University of Hong Kong
Kowloon
Hong Kong
Seyed Omid Rastegar
Department of Chemical Engineering
Faculty of Engineering
University of Kurdistan
Sanandaj
Iran
Rahul Rautela
CSIR-National Environmental Engineering Research Institute (CSIR-NEERI)
Nagpur
Maharashtra
India
and
Academy of Scientific and Innovative Research (AcSIR)
Ghaziabad
Uttar Pradesh
India
Lucas Reijnders
Faculty of Science
IBED
University of Amsterdam
Amsterdam
The Netherlands
Nirmaladevi Saravanan
Department of Biochemistry and Biotechnology
Avinashilingam University for Women
Coimbatore
Tamil Nadu
India
Shahriar Shams
Civil Engineering Programme Area
Universiti Teknologi Brunei
Gadong
Brunei Darussalam
Abhishek Sharma
Department of Veterinary Public Health and Epidemiology
CSK HP Agricultural University
Palampur
Himachal Pradesh
India
Ummul Khair Sultana
School of Chemical Engineering
Faculty of Engineering
Architecture and Information Technology
University of Queensland
Brisbane
QLD
Australia
Ningjie Tan
State Key Laboratory of Bioreactor Engineering
East China University of Science and Technology
Shanghai
China
Shital C. Thacker
Department of Microbiology and Biotechnology
School of Sciences
Gujarat University
Ahmedabad
India
and
Department of Microbiology
Silver Oak Institute of Sciences
Silver Oak University
Ahmedabad
India
Devayani R. Tipre
Department of Microbiology and Biotechnology
School of Sciences
Gujarat University
Ahmedabad
India
James Vaughan
School of Chemical Engineering
Faculty of Engineering
Architecture and Information Technology
University of Queensland
Brisbane
QLD
Australia
Hugo M. Veit
Materials Engineering Department
Federal University of Rio Grande do Sul
Porto Alegre/RS
Brazil
Anusha Vishwakarma
Department of Civil and Environmental Engineering
Indian Institute of Technology Patna
Patna
Bihar
India
Ismawi Yusof
Civil Engineering Programme Area
Universiti Teknologi Brunei
Gadong
Brunei Darussalam
Xu Zhang
State Key Laboratory of Bioreactor Engineering
East China University of Science and Technology
Shanghai
China
Preface
Sustainable living conditions are necessary for a developing society. In order to meet the sustainable development goals for the attainment of a circular economy, there is a need for judicial utilization of natural resources, efficient technologies, effective waste management, recycling tools and techniques to maintain stability and continuity of the supply chain, and conservation of resources. Resource conservation can be facilitated through resource circularization, recycling, and reuse, driving toward zero waste discharge. Waste electrical and electronic equipment (WEEE) or electronic waste (e-waste) is one of the fastest-growing waste streams in the urban environment worldwide. A large portion of e-waste remains unaccounted for and is deprived of treatment through appropriate recycling chains and methods. They are often found to be managed by the informal sector using rudimentary approaches that not only cause environmental pollution but also lead to serious health hazards for the workforce employed. Out of the total e-waste generated, only a small share is collected formally by the take-back system, while the rest is disposed of in waste bins, which finally reach incinerators, landfills, and open dump yards. E-waste is a significant source of base, precious, and toxic metals. The composition of e-waste is diverse, and it contains a complex array of metals in quantities even higher than their natural deposits. This high metallic content contributes perpetually and comprehensively to the economic vitality of the recycling of metals. In addition, the recovery of metals is also necessary for waste treatment. Therefore, management and recycling of e-waste is an important aspect, not only from the point of waste treatment to avert environmental pollution but also for resource recovery for economic development. The hierarchy of e-waste management recommends the reuse and/or remanufacture of the whole end-of-life electrical and electronic equipment, followed by the recovery of materials by recycling techniques. For the recovery of metals from e-waste, various traditional metallurgical techniques, viz., pyrometallurgy using heat treatments like roasting, smelting, and hydrometallurgy based on chemical leaching, are employed. These processing methods are often demonstrated to be energy intensive, costly, and associated with serious secondary pollution such as the release of toxic gases like dioxins, furans, metal dust, a high volume of hazardous lixiviants, and wastewater. In order to meet the environmental norms for hazardous waste disposal and conservation of natural resources around the world, there is a growing concern for the safe recycling of e-waste. The limitations of conventional techniques have led to a shift toward biotechnological approach. The integration of biotechnology into the hydrometallurgical process by the application of biocatalysts such as microorganisms and enzymes has evolved into a green, safe alternate metallurgical process known as biohydrometallurgy, biometallurgy, or bioleaching technique for e-waste recycling. In comparison to conventional technologies, bioleaching-based processes offer a number of advantages, such as low operation costs, environmental compatibility, relatively low energy consumption, and easy technology for metals extraction. Further, as the majority of the e-waste generated is being managed by the informal sector using rudimentary approaches, bioleaching technology provides an alternative to the metallurgical sector with no environmental and health hazards.
This book comprehensively presents various aspects of e-waste, such as generation, management techniques, role as secondary metal reservoir, different conventional as well as eco-friendly recycling approaches, biotechnological advances, and developments in resource recovery, along with the associated toxicity, risks, and scope for future research. The book aims to present hazards associated with conventional recycling methods and highlights environmentally compatible and economic approaches to resource recovery. A review of the progress in bioleaching technology focused on a sustainable future is also presented in the book. Further, the book fills in the gaps in understudied biotechnological recycling techniques and explores possibilities to mitigate environmental pollution caused by conventional and rudimentary e-waste management and recycling approaches. Some of the latest research and developments in the areas of e-waste management, biotechnological recycling processes, regulations, and policies are also highlighted in the book. A complete overview of all aspects related to the toxicity characterization of e-waste, resource recovery, recycling strategies, biotechnological advancements, and current perspectives on e-waste generation and management is covered in the book. Further, recycling and resource recovery aspects of e-waste under the current global scenarios are conceptualized in this book, adopting a qualitative approach that will facilitate future risk characterization and evaluation. This book is expected to serve as a guideline for producers, consumers, recycling industries, policy and law makers, academicians, and researchers. The book is also expected to contribute to society by creating awareness and knowledge among the general masses and the scientific community regarding pollution abatement and sustainable utilization of resources.
July 26, 2023
Dr. Anshu PriyaCity University of Hong KongHong Kong
Acknowledgment
I extend my deep sense of gratitude to John Wiley & Sons for giving me this wonderful opportunity to publish and spread awareness on one of the most serious issues of urban world – the e-wastes, their hazards, importance, resource recovery, reutilization, management, and regulations. My immense thanks goes to the researchers and scientists who helped me with their innovative suggestions, vast knowledge, scientific advice, and expertise that led to successful completion of this book. I would like to convey my heartfelt gratitude to all the authors and contributors of this book for their insightful articles, kind cooperation, and unstinted support. The love of my parents and family has always been outstanding. I owe my deepest and warmest gratitude to my grandparents, parents, brother, family members, and friends for their unparallel love, care, support, and encouragement. I convey my deep sense of appreciation to my husband, Dr. Ambresh Shivaji, for his motivation, consideration, and constant support. Words will not suffice to acknowledge their constant support throughout this work. A special thanks to all my well-wishers whose names I missed out here.
Above all, I express my profound devotion and deepest gratitude to The Almighty for bestowing His blessings upon me.
1An Introduction to Electronic Waste
Anshu Priya
School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
Abstract
Waste electrical and electronic equipment (WEEE) or electronic waste (e-waste) is one of the fastest-growing waste streams worldwide. The rich metallic content of e-waste makes them secondary reservoir of many base, precious, rare earth, and toxic metals. Additionally, several nonmetallic constituents, such as brominated flame retardants, in quantities higher than the permissible limit make them hazardous in nature. Thus, the management, treatment, and resource recovery of e-waste are essential not only for economic development but also to avert environmental pollution. The problem of e-waste generation is more prominent in developed and developing economies. Further, the problem gets compounded by the transboundary movement of e-waste despite the Basel Convention Prohibition (1992). The evaluation of their generation, flow in economy, and composition are essential elements for development and implementation of various eco-friendly recycling approaches, sustainable reprocessing technologies, and sound policies for a sustainable, green, and circular economy.
Keywordse-waste; metal resources; recycling technologies; management approaches; sustainable and circular economy
1.1 Introduction
The unprecedented digitalization and urbanization over the past few decades, coupled with a rapid product obsolescence rate, have led to enormous generation of waste electrical and electronic equipment (WEEE) or electronic waste (e-waste), ranking it among the fastest-rising waste streams worldwide. China was reported to generate the highest e-waste, with more than 10 million metric tons (Mt) in 2019. The United States followed China with around 7 Mt and was the second-largest e-waste generator. As per the report by the United Nations University (UNU 2015), 53.6 Mt of e-waste were estimated to be generated in the year 2019 (Baldé et al. 2022). The generation trend was further anticipated to increase to 74.7 Mt. by 2030 (Forti et al. 2020).
E-waste includes a wide range of components and constituents from polymers, glass, and ceramics to valuable resources like metals. Base metals, precious metals, toxic metals, as well rare earth metals (REMs) such as Cu, Zn, Cd, Pb, Hg, Ni, Co, Al, Fe, Sn, Au, Ag, Pd, Nd, Ce, and La are integral constituents of e-waste. It has been reported that the concentration of metals in e-waste is in sufficiently rich quantity, many times even higher than their natural repository (Konaté et al. 2022). The rich metallic content of e-waste thus makes waste a good secondary source of metals. Thus, the removal of metals is subject of utmost concern not only for treatment of waste but also for recovery of metallic fractions. Reprocessing of waste metals generated from electric and electronic equipment is vital, as it not only allows waste management, treatment, and resource recovery but also averts environmental pollution. However, management of e-waste is a challenge due to the fact that the current recycling technologies include either pyrometallurgical or hydrometallurgical processes, which are energy-concentrated, costly, and also associated with environmental problems linked to the release of toxic gases like dioxins, furans, metal dusts, and lixiviants (Dutta et al. 2023). Therefore, it is urgent to develop an appropriate recycling technology for reprocessing of WEEE in cost-effective and environmentally compatible manner.
Biotechnology has thus proven to be a dominating and versatile substitute for the existing conventional recycling methods for tackling various problems related to environmental pollution because of its low energy demand, less inputs, low waste generation, and emissions (Brindhadevi et al. 2023). To date, several biotechnologies have been subjugated in well-developed, mechanized systems that can be categorized under the heading “biohydrometallurgy.” This technique exploits biological activities for efficient recovery of metal. Through these processes, metallic compounds are converted into their water-soluble states through a process called microbial leaching (Atlas and Bartha 1997). Over the past few years, studies related to biological leaching have shown to play a significant role in metal mobilization. Now there is a need for shifting the application of microbiological leaching process to extract metals from various wastes. There are many microorganisms that are reported to have significant role in metal recovery from industrial waste. Among the bacteria, sulfur-oxidizing bacteria, especially those of Thiobacillus spp. (also called Acidithiobacillus spp.), such as Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans, and Sulfolobus sp., are some of the well-known bioagents conducting bioleaching (Trivedi and Hait 2023; Qiu and Liu 2022; Trivedi et al. 2022). Metals present as leachate in the leached liquor are recovered using solvent extraction, adsorption, ion exchange, precipitation, cementation, and electrowinning. Compared with conventional methods for removing toxic metals from leached liquor, the biosorption process has the advantages of biodegradability, low operational cost, reduced volume of chemicals and biological sludge to be disposed of, and high efficiency in detoxifying very dilute liquors (Rivas-Castillo et al. 2022).
The challenges in the management of e-waste using sustainable reprocessing technologies that are able to address the e-waste using economically and ecologically responsive methods have encouraged need of active attempts in the area. This book presents a comprehensive insight into the various metallurgical processes, policies, laws, hazards, life cycles, and techno-economic assessments involved in the recovery and management of e-waste.
1.2 Generation and Composition of E-Waste
The advent of new, sophisticated inventions, advanced technologies, and substantially shortened life span of many electronic commodities has kicked out many electronic items from the consumer's hands, which ultimately builds up e-waste. A drastic increase in e-waste generation is being observed with the rising economy and mounting demand for EEE. As per a study conducted by UNU, Asia produced the highest volume of e-waste with generation of 24.9 Mt, followed by the United States with 13.1 Mt and Europe with 12 Mt, while the contributions by Africa and Oceania were 2.9 and 0.7 Mt, respectively (Baldé et al. 2022). China ranked first in e-waste generation with 10.1 Mt, followed by the United States Of America with 6.9 Mt, and India with 3.2 Mt. Japan and Brazil share almost the same platform with 2.6 and 2.1 Mt, respectively. Table 1.1 presents e-waste generation data for the year 2019 for the major economies of the world (Baldé et al. 2022). The developed and emerging economies contribute to a significant portion of global e-waste. E-waste generation has been shown to have a direct correlation with both population and purchasing power of the masses. Income level and purchasing power are powerful drivers of the economy and govern e-waste production. With the increase in per capita purchasing power of developing economies, there is a significant transition toward industrialization and e-waste generation (Puntillo 2023).
Table. 1.1 E-waste generation for the major economies of the world for the year 2019.
Country/region
Total e-waste generated (Mt) in 2019
China
10.1
United States
6.9
India
3.2
Japan
2.6
Brazil
2.1
Russia
1.6
Indonesia
1.6
Germany
1.6
United Kingdom
1.6
France
1.4
Source: Adapted from Baldé et al. (2022).
The complexity and heterogeneity of e-waste owe to its various constituents. It has been estimated that one personal computer is usually composed of 40% steel, 21% plastic, 10% Al, and 10% other metals such as Cu, Cd, Au, Pt, and Ag (Brindhadevi et al. 2023). The lithium batteries, an important power source of electronic devices, contain 2–7% Li and 5–15% Co as basic constituents (Neumann et al. 2022). Co being an expensive metal is recycled from spent batteries. Printed circuit board (PCB) an important component of electrical and electronic goods contains the majority of metals; however, the actual composition varies with type of PCB. The complex compositions of e-waste make them a rich recovery source. The hazardous components present in e-waste are of serious concern and mainly include metals such as As, Cr(IV), Co, Hg, Pb, and Ni. These are considered hazardous as they are bioaccumulative, can concentrate in cells, and further carried on to the successive tropic level, where they produce deleterious impact (Brindhadevi et al. 2023). Recycling thus turns e-waste into a secondary reserve for the recovery and recycling of metals and nonmetals, thereby reducing their environmental and health hazards as well as finding a way out to solve metal crisis (Islam et al. 2020).
1.3 Present Status of E-Waste Management and Recycling
As per a study conducted by UNU, only 17% of the total global e-waste generated in 2019 was officially recognized to be collected and managed in an environmentally viable manner, thus ensuring the recycling of a gross value of US $9.4 billion of metals such as Fe, Au, and Cu. The fate of the remaining 44.3 Mt, making up about 83% of e-waste generated in 2019, was undocumented and not known (Baldé et al. 2022). Efficient management and handling of e-waste can help alleviate global warming and global greenhouse gas emissions. The high metallic content and heterogeneous and composite nature of e-waste make them hazardous and rich secondary sources for recovery of metals. Environmental pollution caused by the metal content of e-waste is very noticeable in dumping areas, landfills, and incinerators. The dumped discarded metals leach out, generate toxic emissions on burning, and contaminate air, water, and soil (UNEP 2009). Metallic mercury, dimethyl mercury, Pb, and Cd are the most toxic leachates. Landfills and incinerators are also very much prone to uncontrolled fires and the release of harmful gases and toxic slag through which the metals reenter the environment (Murali et al. 2022). Taking all these into consideration, there is an urgent need to take up the “R” endeavors, i.e. Reduce, Reuse, and Recycle. The drift toward reducing the use of metals must be encouraged; however, the other two that deserve special attention are reuse and recycle. The benefits of metal recycling are depicted in Figure 1.1.
Figure 1.1 Benefits of e-waste recycling.
Recycling of e-waste from old, unused appliances or devices involves manual dismantling and segregation of the WEEE components like the metallic and nonmetallic fractions. Following sorting, the metallic components are shredded and then subjected to recovery. The recovery of metals from e-waste involves a number of mechanical, physical, chemical, and biological processes (Islam et al. 2020).
1.3.1 Pyrometallurgical Process
Pyrometallurgical processes include thermal treatment of the shredded metallic fractions in controlled high-temperature environment to recover the metals of interest (Hartley et al. 2023). The heat treatment is given in specialized furnaces such as incinerators, plasma arc furnaces, or blast furnaces where reactions between the metallic oxides and the reducing agent such as charcoal or coke are carried out releasing carbon dioxide (CO2). The nonmetallic fraction, i.e. gangue is heated with substance called flux to form slag. Slag is a molten mass that, being lighter than the metallic fraction, floats over it and can be easily decanted off (Ebin and Isik 2016).
Figure 1.2 Generalized steps involved in pyrometallurgical recovery of metals from e-waste.
A number of modifications have been proposed to the conventional pyrometallurgical processes to improve their yield as well as reduce their environmental hazardous impact. Wang et al. 2020) modified the gold refining process through reaction of gold scrap and chlorine. The resultant was washed with hydrochloric acid, ammonium hydroxide, and nitric acid to remove the impurities. Au with 99.9% purity was recovered by this process. Abdelbasir et al. (2018) applied vacuum pyrolysis and extracted Cu with 99% purity. Umicore's smelter trial recovered metals from electronic scrap by replacing the reducing agent coke and the energy source with plastic-rich WEEE materials (Castro and Bassin 2022). However, an important disadvantage linked to pyrometallurgical process is the emission of harmful gases and compounds, such as polybrominated dibenzodioxins (PBDD), polybrominateddibenzofurans (PBDF), phenol, naphthalene, biphenyl, anthracene or phenanthrene, dibromobenzene, dibenzofuran, dibenzo-p-dioxin, tribromobenzene, tetrabromobenzene, and many more, leading to serious environmental pollution (Hartley et al. 2023). Figure 1.2 shows generalized steps involved in pyrometallurgical metal recovery.
1.3.2 Hydrometallurgical Process
In conventional hydrometallurgical process, leaching of metals is carried out using suitable lixiviants. The crushed e-waste scrapes are subjected to various chemicals of acidic and basic nature such as aqua regia, nitric acid, sulfuric acid, thiourea, thiosulfate, cyanide, and halide to leach out the metals from them. Cyanide leaching is most widely used for effective and economic extraction of gold and can efficiently extract 1–3 g/t of Au, but the major drawback is that the chemical possesses environmental toxicity. Thiosulfate and thiourea also have fast leaching rate but low chemical stability. Acid leaching is conducted usually as first-stage leaching to recover base metals, especially Cu (Ashiq et al. 2019). Chemical leaching exploiting various chemical ligands such as ethylene diamine tetramaide (EDTA), diethylene triamine penta acetate (DTPA), and other chelators like oxalate and citric acid have also been exploited for metal extraction (Xavier et al. 2023). The metals are then purified through techniques such as electrorefining, solvent extraction, and adsorption. Figure 1.3 shows schematic representation of hydrometallurgical metals recovery. The wastewater generated in the whole process of recovery is extremely hazardous toxic and difficult to recycle (Islam et al. 2020).
Various improvements have been introduced in the existing pyrometallurgical process. Rath et al. 2012), coupled thermal plasma with acid leaching to improve metal recovery. This technique generates less effluent and offers fast separation of slag metal. Ultrasonic-assisted cleaner pyrometallurgical technique has also been shown to efficiently extract metals with less toxicant generation. The technique recovered Cu and Fe with an efficiency of 95.2–97.5% and 97.1–98.5%, respectively (Xie et al. 2009). In another approach, a combination of thermal and acid treatment was proposed for faster and more reliable gold dissolution and recovery (Mahapatra et al. 2019).
1.3.3 Biometallurgy
Biometallurgy, also known as biohydrometallurgy or bioleaching, is a novel technique aiming at efficient, green, and economic metal recovery (Figure 1.4). It is based on microbial solubilization of metals, through which they convert metals into soluble, extractable form. The leached metals in liquor are then adsorbed on suitable biological matrix and finally recovered. Microbes capable of secreting various organic and inorganic acids are exploited in this process to recover different metals from various low-grade sources (Arab et al. 2020; Dey et al. 2023). The frequently used microorganisms applied in bioleaching are acidophilic Fe- and sulfur-oxidizing bacteria such as Thiobacillus ferrooxidans, T. thiooxidans, L. ferrooxidans, and Sulfolobus spp., and fungi such as Aspergillus niger and Penicillium spp. to extract the target metals from waste (Dey et al. 2023). Apart from these, a number of heterotrophic bacteria, such as those of the genus Bacillus and Pseudomonas, also have the potential to extract nonsulfidic minerals (Hubau and Bryan 2023).
Figure 1.3 Schematic representation of hydrometallurgical recovery of metals from e-waste.
Heterotrophic bioleaching microorganisms derive carbon and energy from organic carbon sources, and as a result of consumption, they produce a number of metabolic by-products such as citric acid, oxalic acid, and formic acid, which interact with the metallic waste to leach out metals (Dey et al. 2023; Hubau and Bryan 2023). However, there are several factors that regulate the metal bioleaching; these factors can be optimized to maximize the biological metal extraction. The parameters include biotic factors such as the characteristics and type of microorganisms used and size of inoculums, and abiotic factors such as growth environment, pH, temperature, aeration rate, particle size of extractable e-waste sources, incubation time, and nutritional composition of media (Valix 2017; Yang et al. 2009). Various researchers have extracted metals using bioleaching reactions. Yang et al. (2009) observed the effects of concentrations of iron, pH, inoculum size, and concentration on Cu extraction by A. ferrooxidans. Ilyas et al. (2007) successfully used acidophilic heterotrophic bacteria to recover more than 80% of metals such as Al, Cu, Ni, and Zn from PCBs. Baldé et al. (2022) demonstrated the application of T. thiooxidans and A. niger in the recovery of metals from e-scrape. Faramarzi et al. (2004) applied cyanogenic Chromobacterium violaceum for bioextraction of Au from PCBs. Cu and Au are among the vital metals that are industrially extracted through biometallurgy (Ilyas et al. 2007).
Figure 1.4 Schematic representation of biohydrometallurgical recovery of metals from e-waste.
1.4 Comparative Assessment of the Metallurgical Options for Metal Recovery
The three most widely employed metallurgical options, pyrometallurgy, hydrometallurgy, and biometallurgy are central apparatus for metal recovery. Choosing an appropriate metal recovery option is very much dependent on its extractability, economics, time, involvement of labor, and compatibility with the environment.
Extraction parameters such as environmental compatibility, economics, engagement of labor, expertise, waste type, and metal content in waste must be assessed before the selection of a metallurgical technique. Pyrometallurgical process involves thermal treatment and hence generates tremendous amount of hazardous gases and dust. Burning of plastics and other inorganic and organic waste constituents generates hazardous gases such as furans, dioxins, CO2, CO, SO2, NOx, and various poisonous volatile compounds. Besides these, incineration produces ashes with high content of metals such as Cd, Pb, and As. Hydrometallurgical and biometallurgical treatments extract metals in soluble form and hence generate large amounts of wastewater; however, biometallurgy generates comparatively less amount of wastewater than hydrometallurgy (Dey et al. 2023). Types of wastewater include spent acids, cooling water, and washdowns.
Taking mass balance into consideration, pyrometallurgical method leads to higher losses of metals in the form of metal dust, slag, and refractories. Hydrometallurgy offers high recovery and less metal with relative ease of leaching. Biometallurgy exhibits a higher rate because of involvement of active bioagents, which can extract metals even from depleted, low-grade sources, and possibility of recirculation of leached liquor in the method (Trivedi and Hait 2023). A large amount of fuel and energy are also required in the pyrometallurgical process as compared to hydrometallurgical, while the energy requirement is the least in biometallurgy (Dey et al. 2023). Biometallurgical technique is the most time-consuming, labor-intensive, and requires expertise as compared to the other two metallurgical techniques (Hubau and Bryan 2023).
The expenses involved in current conventional metallurgical methods have necessitated need for exploration of efficient alternatives for waste management and metal recovery. Potential factors affecting metal recovery also include the cost of operation and maintenance, that is, the investment capital. The profitability of recycling methods drastically depends on the economics of the metallurgical technique.
1.5 Future Prospects
E-waste, especially PCBs, contains a wide range of metals in sufficient quantities, which get dumped when the equipment becomes obsolete. The conventional recovery techniques are costly, high energy consuming, and environmentally incompatible. Bioleaching, on the other hand, is economic and green approach for recovery of metals from e-waste and other low-grade metal repositories. However, the research in this area is very limited, on a laboratory scale, and has not yet developed at industrial scale. Process can be designed using agro- or food-industrial wastes as a growth medium for heterotrophic leaching microorganisms to carry out bioleaching. The limitation of bioleaching process is the inherently long operational time, which can be reduced through approaches such as genetic manipulation or the integration of other safe approaches such as physical and chemical approaches. Interdisciplinary research involving areas encompassing microbiology, chemical engineering, biotechnology, metallurgy, and biochemical engineering is required to take bioleaching to profitable commercial applications.
1.6 Conclusion
Environmental pollution by e-waste is very noticeable in dumping areas. The dumped metals leach out under the influence of physical, chemical, and biological factors of environment; their volume reduction by burning also generates toxic emissions and contaminates air, water, and soil. The high metallic content and heterogeneous and composite nature of e-wastes, however, make them rich secondary sources of metals. But the current recycling technologies, hydro, and pyrometallurgical techniques are environmentally incompatible, energy-concentrated, and uneconomic. Thus, there is an urgent need for recycling of metals, in eco-friendly, cost-effective way, to avert pollution with focus on economic metals recovery. Bioleaching of metals from e-waste emerged as a new approach for metal recovery in an environment-friendly manner. However, for maximizing the rate of recovery, certain biotic and abiotic factors must be taken into consideration and optimized so as to convert the process to a profitable one. Studies conducted on bioleaching show disparity in the process factors governing metal biodissolution. The same microorganism is shown to have different process requirements for metal recovery. Thus, there is a need to bridge the gaps present in the existing studies for efficient and profitable metal recovery by bioleaching.
References
Abdelbasir, S.M., El-Sheltawy, C.T., and Abdo, D.M. (2018). Green processes for electronic waste recycling: a review.
Journal of Sustainable Metallurgy
4 (2): 295–311.
Arab, B., Hassanpour, F., Arshadi, M. et al. (2020). Optimized bioleaching of copper by indigenous cyanogenic bacteria isolated from the landfill of e-waste.
Journal of Environmental Management
261: 110124.
Ashiq, A., Kulkarni, J., and Vithanage, M. (2019). Hydrometallurgical recovery of metals from E-waste. In:
Electronic Waste Management and Treatment Technology
, 225–246. Oxford: Butterworth-Heinemann.
Atlas, R.M. and Bartha, R. (1997).
Microbial Ecology: Fundamentals and Applications
. California: Benjamin Cummings.
Baldé, C.P., D'Angelo, E., Luda, V. et al. (2022).
Global Transboundary e-Waste Flows Monitor – 2022, United Nations Institute for Training and Research (UNITAR)
. Germany: Bonn.
Brindhadevi, K., Barceló, D., Chi, N.T.L., and Rene, E.R. (2023). E-waste management, treatment options and the impact of heavy metal extraction from e-waste on human health: scenario in Vietnam and other countries.
Environmental Research
217: 114926.
Castro, F.D. and Bassin, J.P. (2022). Electronic waste: environmental risks and opportunities. In:
Hazardous Waste Management
, 421–458. Amsterdam: Elsevier.
Dey, S., Shekhawat, M.S., Pandey, D.K. et al. (2023). Microbial community and their role in bioremediation of polluted e-waste sites. In:
Metagenomics to Bioremediation
, 261–283. Cambridge: Academic Press.
Dutta, D., Rautela, R., Gujjala, L.K.S. et al. (2023). A review on recovery processes of metals from E-waste: a green perspective.
Science of the Total Environment
859: 160391.
Ebin, B. and Isik, M.I. (2016). Pyrometallurgical processes for the recovery of metals from WEEE. In:
WEEE Recycling
, 107–137. Amsterdam: Elsevier.
Faramarzi, M.A., Stagars, M., Pensini, E. et al. (2004). Metal solubilization from metal-containing solid materials by cyanogenic Chromobacterium violaceum.
Journal of Biotechnology
113 (1–3): 321–326.
Forti, V., Baldé, C.P., Kuehr, R., and Bel, G. (2020). The global e-waste monitor 2020: quantities, flows and the circular economy potential. In:
United Nations University (UNU)/United Nations Institute for Training and Research (UNITAR) – Co-Hosted SCYCLE Programme
. Bonn/Geneva/Rotterdam: International Telecommunication Union (ITU) & International Solid Waste Association (ISWA).
Hartley, J.M., Scott, S., Rivera, R.M. et al. (2023). Tailoring lixiviant properties to optimise selectivity in E-waste recycling.
RSC Sustainability
1 (1): 107–116.
Hubau, A. and Bryan, C.G. (2023). Metal recovery from E-wastes. In:
Biomining Technologies
, 239–259. Cham: Springer.
Ilyas, S., Anwar, M.A., Niazi, S.B., and Ghauri, M.A. (2007). Bioleaching of metals from electronic scrap by moderately thermophilic acidophilic bacteria.
Hydrometallurgy
88 (1–4): 180–188.
Islam, A., Ahmed, T., Awual, M.R. et al. (2020). Advances in sustainable approaches to recover metals from e-waste – a review.
Journal of Cleaner Production
244: 118815.
Konaté, F.O., Ancia, P., Soma, F. et al. (2022). Waste electrical and electronic equipments as urban mines in Burkina Faso: characterization and release of metal particles.
Waste Management
139: 17–24.
Mahapatra, R.P., Srikant, S.S., Rao, R.B., and Mohanty, B. (2019). Microwave heating and acid leaching processes for recovery of gold and other precious metals from e-waste.
Current Science
116 (3): 463–468.
Murali, A., Plummer, M.J., Shine, A.E. et al. (2022). Optimized bioengineered copper recovery from electronic wastes to increase recycling and reduce environmental impact.
Journal of Hazardous Materials Advances
5: 100031.
Neumann, J., Petranikova, M., Meeus, M. et al. (2022). Recycling of lithium-ion batteries—current state of the art, circular economy, and next generation recycling.
Advanced Energy Materials
12 (17): 2102917.
Puntillo, P. (2023). Circular economy business models: towards achieving sustainable development goals in the waste management sector—empirical evidence and theoretical implications.
Corporate Social Responsibility and Environmental Management
30 (2): 941–954.
Qiu, G.Z. and Liu, X.D. (2022). Biotech key to unlock mineral resources value.
Transactions of Nonferrous Metals Society of China
32 (7): 2309–2317.
Rath, S.S., Nayak, P., Mukherjee, P.S. et al. (2012). Treatment of electronic waste to recover metal values using thermal plasma coupled with acid leaching–a response surface modeling approach.
Waste Management
32 (3): 575–583.
Rivas-Castillo, A.M., Gómez-Ramírez, M., Lucas-Gómez, I.M. et al. (2022). A new technique to evaluate Acidithiobacillus thiooxidans growth during a bioleaching process based on DNA quantification.
Journal of Microbiological Methods
198: 106494.
Trivedi, A. and Hait, S. (2023). Metal bioleaching from printed circuit boards by bio-Fenton process: optimization and prediction by response surface methodology and artificial intelligence models.
Journal of Environmental Management
326: 116797.
Trivedi, A., Vishwakarma, A., Saawarn, B. et al. (2022). Fungal biotechnology for urban mining of metals from waste printed circuit boards: a review.
Journal of Environmental Management
323: 116133.
UNEP (2009).
Recycling – from E-waste to Resources
. Paris: United Nations Environmental Programme (UNEP).
UNU (2015).
E-Waste World Map: Update to Quantitative Data and Legal Texts – STEP
. United Nations University (UNU).
Valix, M. (2017). Bioleaching of electronic waste: milestones and challenges.
Current Developments in Biotechnology and Bioengineering
1: 407–442.
Wang, J., Zhang, M., and Lu, Y. (2020). Study of gold leaching behavior in the chlorination process from waste printed circuit boards.
ACS Sustainable Chemistry & Engineering
9 (1): 284–290.
Xavier, L.H., Ottoni, M., and Abreu, L.P.P. (2023). A comprehensive review of urban mining and the value recovery from e-waste materials.
Resources, Conservation and Recycling
190: 106840.
Xie, F., Cai, T., Ma, Y. et al. (2009). Recovery of Cu and Fe from printed circuit board waste sludge by ultrasound: evaluation of industrial application.
Journal of Cleaner Production
17 (16): 1494–1498.
Yang, T., Xu, Z., Wen, J., and Yang, L. (2009). Factors influencing bioleaching copper from waste printed circuit boards by Acidithiobacillus ferrooxidans.
Hydrometallurgy
97 (1–2): 29–32.
