Metal-Organic Frameworks (MOFs) for Environmental Applications

Sujit K. Ghosh

• Publisher: Elsevier
• Year: 2019
• ISBN:
  9780128146347
• Topic: Physical Sciences
• Subtopic: Inorganic Chemistry

Metal-Organic Frameworks for Environmental Applications examines this important topic, looking at potential materials and methods for the remediation of pressing pollution issues, such as heavy-metal contaminants in water streams, radioactive waste disposal, marine oil-spillage, the treatment of textile and dye industry effluents, the clean-up of trace amounts of explosives in land and water, and many other topics. This survey of the cutting-edge research and technology of MOFs is an invaluable resource for researchers working in inorganic chemistry and materials science, but it is also ideal for graduate students studying MOFs and their applications.

• Examines the applications of metal-organic frameworks for the remediation of environmental pollutants
• Features leading experts who research the applications of MOFs from around the world, including contributions from the United States, India and China
• Explores possible solutions to some of today's most pressing environmental challenges, such as heavy-metal contamination in bodies of water, oil spills and clean-up of explosives hidden in land and water
• Provides an excellent reference for researchers and graduate students studying in the areas of inorganic chemistry, materials chemistry and environmental science

1

Introduction

Sujit K. Ghosh^1,2* and Susumu Kitagawa³*,    ¹Centre for Energy Science, Indian Institute of Science Education and Research (IISER), Pune, India,    ²Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, India,    ³Institute for Integrated Cell-Material Science (iCeMS), Kyoto, Japan*, Corresponding authors: e-mail address: [email protected] and [email protected]

Abstract

The field of metal-organic frameworks or porous coordination polymers has witnessed a remarkable upsurge over the last few years owing to the wide array of applications realized by these materials. In this regard, remediation of environmental pollutants has commanded significant attention owing to pressing concerns globally. This chapter intends to brief the reader of the various aspects involving material development of specific applications along with their considerations while evaluating real-time performance. This chapter also outlines the scope and contents of the book and gives a brief glimpse of the span covered in this book.

Keywords

Metal-organic frameworks; porous coordination polymers; environmental pollution; air pollution; water pollution; adsorption; capture; sequestration; sensing

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) form a distinguished subset in the domain of coordination chemistry: they are broadly regarded as coordination networks bearing potential voids [1]. Constructed from organic struts which extend infinitely in a periodic manner through metal nodes, MOFs represent an advanced class of porous materials that have been subject to a remarkable upsurge over the last few decades. The myriad choice of building blocks along with access to combinatorial chemistry affords the synthesis on demand of architectures whose properties can be directly linked to the structural characteristics. These features have made MOFs highly sought-after over congener porous solid materials, for example, zeolites and activated carbon. Further, the ability to modulate nanospace properties, control pore size and nature, access mesoporosity, utilize reticular chemistry, and incorporate active sites in porous compounds as per demand has resulted in MOFs commanding research interest across disciplines. The spectrum of potential applications using MOFs has broadened with the evolution of this field, which prominently include gas storage/separation, adsorptive separation of industrially challenging liquid mixtures, ion-conduction, sensing and photonics, heterogeneous catalysis, drug delivery, etc. [2,3].

The rise of MOF chemistry can be primarily ascribed to the following broad reasons: growing knowledge of structural characteristics retrieved from a library of reported compounds, and the greater precision to obtain read-out and control host–guest chemistry in different media. In particular the rise of third generation of MOFs (soft porous crystals) has actuated the development of MOFs toward applications based on such host–guest chemistry [4]. The ability to have guest-responsive structural dynamics has further propelled their ability to operate as functional solids with a high precision and selectivity of guest accommodation and recognition response. Apart from softness, MOFs bear the inherent ability to incorporate specific active sites which have promoted the applicability of these compounds toward a wide array of gas or liquid adsorption, which are either environmentally noxious or industrially relevant. In addition to the liberty of designing a specific probe/sorbent, MOFs offer the choice to pick transduction mechanisms based on the specific field of application, such as electromagnetic responses, photonic responses, and naked-eye colorimetry. Other than conventional applications, recently MOFs have started demonstrating affirmative potential toward their utility in the recognition, capture, and detoxification of environmental toxins that are present in different media including air, water, and soil.

Addressing environmental pollution has become one of the greatest challenges for human civilization in the 21st century. This is clearly reflected in the list of sustainable development goals benchmarked by the United Nations [5]. The direct correlation in the higher emission or release of toxic species with the change in ecological balance has prompted the pressing need to curb the presence of pollutants. For instance, in 2018, a report by World Health Organization (WHO) raised the alarm, by suggesting that more than 90% of the human population on Earth is breathing polluted air [6].

Porous materials have emerged as suitable receptors to entrap environmental pollutants or detoxify them into safe substances on account of very high surface areas, high porosity, and ease in design of molecular scale functional voids. Due to several advantages MOFs score over conventional porous adsorbents, but the major bottleneck in pursuit of MOFs realizing applicability in this domain has been the stability under operating conditions or susceptibility of MOF compounds to decompose upon exposure to moisture. Recently, there has been a conscious effort in the field to address this issue and encouraging progress and long-term promise has been witnessed [7]. Apart from stability, another issue which has retarded the investigation of MOFs under real-time conditions has been the lack of strategies to form devices from microcrystalline MOF powders. Hence, composites based on MOFs have received greater attention, and more intensive research in this regard can propel the realization of MOF-based devices [8]. In addition to these major roadblocks, issues such as toxicity, durability, life-cycle assessment studies (LCA), bulk-scale synthesis, and cost-effectiveness are unavoidable and require careful consideration while proposing the utility of a newly developed material in real-time scenarios [9,10].

The book attempts to focus on the progress of MOFs and understand the long-term trends which have been studied and proposed by the leading names across the globe. Chapter 8, Metal-organic frameworks for detection and desensitization of environmentally hazardous nitro-explosives and related high energy materials, by Ghosh and coworkers emphasizes the utility of MOFs toward sensing and desensitization of nitroaromatic compounds (NACs) and related explosive compounds. Chapter 2, Metal-organic framework-based carbon capture and purification technologies for clean environment, by Zaworotko and coworkers revisits the major milestones in the domain of MOFs for the storage and separation of greenhouse gas carbon dioxide (CO₂) and explains the roadmap going ahead. Carreon and coworkers have described the role of MOFs as heterogeneous catalysts for the greener ways of generating fuels in Chapter 9, Green deoxygenation of fatty acids to transport fuels over metal-organic frameworks as catalysts and catalytic supports. The subsequent two chapters, Chapter 3, Sensing and sequestration of inorganic cationic pollutants by metal-organic frameworks (Ma and coworkers) and Chapter 4, Metal-organic frameworks for recognition and sequestration of toxic anionic pollutants (Ghosh and coworkers), deal with the various approaches wherein MOFs have been able to sense or trap ionic pollutants. Chapter 5, Metal-organic frameworks for the capture of volatile organic compounds and toxic chemicals, by Serre and coworkers discusses the state-of-art for utilizing MOFs for air-pollution control. Chapter 6, Metal-organic frameworks for capture and detoxification of nerve agents, by Farha and coworkers extends the discussion in previous chapter and highlights the progress of MOFs toward the capture and detoxification of chemical warfare agents. Zhou and coworkers (Chapter 7: Metal-organic frameworks for capture and degradation of organic pollutants) and Maji and coworkers (Chapter 10: Potential of hydrophobic metal-organic framework-based materials for environmental applications) provide a flavor of the research carried out toward remediation of water pollution with the focuses on degradation of organic pollutants and separation of oil–water mixtures, respectively. The growing dependence on nuclear power has resulted in the emission of high quantum of nuclear waste in aqueous streams. Wang and coworkers (Chapter 11: Radionuclide sequestration by metal-organic frameworks) describe the progress of MOFs toward the capture of such radioactive species. Finally the chapter by Ricco and coworkers (Chapter 12: Metal-organic framework-based devices for detection and removal of environmental pollutants) gives the reader a flavor of the research in the community devoted toward the development of MOFs in workable forms or as components of portable devices.

All the contributing authors are thanked for their insightful contributions, and the Elsevier team are thanked for all the backroom support. The book endeavors to provide the reader, either in academia or industry, with an essence of the research in the domain of MOFs devoted toward pressing practical concerns, and the editor hopes that the wide array of topics covered in this book can accomplish that objective.

References

1. Batten SR, Champness NR, Chen X-M, et al. Terminology of metal–organic frameworks and coordination polymers (IUPAC Recommendations 2013). Pure Appl Chem. 2013;85:1715–1724.

2. Furukawa H, Cordova KE, O’Keeffe M, Yaghi OM. The chemistry and applications of metal-organic frameworks. Science. 2013;341:1230444.

3. Yuan S, Feng L, Wang K, et al. Stable metal–organic frameworks: design, synthesis, and applications. Adv Mater. 2018; https://doi.org/10.1002/adma.201704303.

4. Horike S, Shimomura S, Kitagawa S. Soft porous crystals. Nat Chem. 2009;1:695–704.

5. www.un.org/sustainabledevelopment/sustainable-development-goals/.

6. http://www.who.int/airpollution/data/cities.

7. Howarth AJ, Liu Y, Li P, et al. Chemical, thermal and mechanical stabilities of metal–organic frameworks. Nat Rev Mater. 2016;1:15018.

8. Falcaro P, Ricco R, Doherty CM, Liang K, Hill AJ, Styles MJ. MOF positioning technology and device fabrication. Chem Soc Rev. 2014;43:5513–5560.

9. Julien PA, Mottillo C, Friscic T. Metal–organic frameworks meet scalable and sustainable synthesis. Green Chem. 2017;19:2729–2747.

10. Grande CA, Blom R, Spjelkavik A, Moreau V, Payet J. Life-cycle assessment as a tool for eco-design of metal-organic frameworks (MOFs). Sust Mater Technol. 2017;14:11–18.

2

Metal-organic framework based carbon capture and purification technologies for clean environment

Soumya Mukherjee, Amrit Kumar and Michael J. Zaworotko*, Department of Chemical Sciences, Bernal Institute, ...