Flue-gas desulfurization

Flue-gas desulfurization (FGD) is a set of technologies used to remove sulfur dioxide () from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration, petroleum refineries, cement and lime kilns. Methods Since stringent environmental regulations limiting emissions have been enacted in many countries, is being removed from flue gases by a variety of methods. Common methods used: *Wet scrubbing using a slurry of alkaline sorbent, usually limestone or lime, or seawater to scrub gases; *Spray-dry scrubbing using similar sorbent slurries; *Wet sulfuric acid process recovering sulfur in the form of commercial quality sulfuric acid; *SNOX Flue gas desulfurization removes sulfur dioxide, nitrogen oxides and particulates from flue gases; *Dry sorbent injection systems that introduce powdered hydrated lime (or other sorbent material) into exhaust ducts to eliminate and from process emissions. For

Development of metal-organic frameworks based on N-heterocyclic ligands

Ilia Kochetygov

Metal-organic frameworks (MOFs) have firmly established in the field of porous materials since their early discovery in the 1990s. With a plethora of applications, these materials offer endless possibilities owing to their tunable, modular nature. The vast amount of synthesized MOFs indicates an utmost interest in this topic among researchers in academia and industry. However, bulk scale uses of MOFs for gas storage, catalysis, water purification and complex separations require such MOFs to have a definite, large pore size in the nanometer range. As MOFs are modular, the production of such large pore materials requires a separate synthesis of particular building blocks called ligands. Most pathways to obtain large ligands rely on the use of palladium-catalyzed coupling chemistry, thus incurring enormous costs and low scalability of the corresponding MOFs. In this thesis, we explore metal-organic frameworks based on N-heterocyclic ligands. We show how the use of these heterocycles has allowed us to easily construct ligands and new MOFs with them, and we showcase various applications of these materials. In Chapter 1, we briefly overview the existing state of the art in ligand design for metal-organic frameworks and define thesis aims. In Chapter 2, we show how a new ligand forms a Cu-Sp5 MOF, which has one of the highest CO2/N2 adsorption selectivities in flue gas conditions reported to date. We investigate the origins of such remarkable performance via multiple characterization techniques. Chapter 3 reports a new MOF Cu-Sp5-BF4. We for the first time access N-heterocyclic carbene (NHC) adduct chemistry in a MOF via ligand post-synthetic modification. We then reveal how this process alters the dimensionality of the material and how it improves the accessibility of NHC sites for a second-step iridium grafting. We finally shed light on iridium speciation in the final material using a combination of EXAFS and XPS methods, and how it changes upon a catalytic reaction of stilbene hydrogenation. Chapter 4 illustrates a new approach for ligand synthesis for large pore MOFs. We show the development of a new concept in ligand design that we call LigX. Using the LigX approach, we simplify large pore MOF ligand synthesis by avoiding time- and cost-intensive Pd-based chemistry. We show the synthesis of structurally diverse MOFs using this methodology.

EPFL2022

Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture

Johanna Maria Huck, Rocio Mercado, Berend Smit, Hui Wang

Porous covalent polymers are attracting increasing interest in the fields of gas adsorption, gas separation, and catalysis due to their fertile synthetic polymer chemistry, large internal surface areas, and ultrahigh hydrothermal stabilities. While precisely manipulating the porosities of porous organic materials for targeted applications remains challenging, we show how a large degree of diversity can be achieved in covalent organic polymers by incorporating multiple functionalities into a single framework, as is done for crystalline porous materials. Here, we synthesized 17 novel porous covalent organic polymers (COPs) with finely tuned porosities, a wide range of Brunauer Emmett Teller (BET) specific surface areas of 430-3624 m(2) g(-1), and a broad range of pore volumes of 0.24-3.50 cm(3) g(-1), all achieved by tailoring the length and geometry of building blocks. Furthermore, we are the first to successfully incorporate more than three distinct functional groups into one phase for porous organic materials, which has been previously demonstrated in crystalline metal organic frameworks (MOFs). COPs decorated with multiple functional groups in one phase can lead to enhanced properties that are not simply linear combinations of the pure component properties. For instance, in the dibromobenzene-lined frameworks, the bi- and multifunctionalized COPs exhibit selectivities for carbon dioxide over nitrogen twice as large as any of the singly functionalized COPs. These multifunctionalized frameworks also exhibit a lower parasitic energy cost for carbon capture at typical flue gas conditions than any of the singly functionalized frameworks. Despite the significant improvement, these frameworks do not yet outperform the current state-of-art technology for carbon capture. Nonetheless, the tuning strategy presented here opens up avenues for the design of novel catalysts, the synthesis of functional sensors from these materials, and the improvement in the performance of existing covalent organic polymers by multifunctionalization.

American Chemical Society2015

Development of metal-organic frameworks based on N-heterocyclic ligands

Ilia Kochetygov

EPFL2022

Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture

Johanna Maria Huck, Rocio Mercado, Berend Smit, Hui Wang

American Chemical Society2015

Photochemical treatment of persistent organic pollutants in flue gases

Development of metal-organic frameworks based on N-heterocyclic ligands

Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture

Photochemical treatment of persistent organic pollutants in flue gases

Development of metal-organic frameworks based on N-heterocyclic ligands

Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture