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Journal ArticleDOI: 10.1021/ACSSUSCHEMENG.0C07055

Accelerated Synthesis of a Ni2Cl2(BTDD) Metal–Organic Framework in a Continuous Flow Reactor for Atmospheric Water Capture

05 Mar 2021-ACS Sustainable Chemistry & Engineering (American Chemical Society (ACS))-Vol. 9, Iss: 11, pp 3996-4003
Abstract: Atmospheric water capture (AWC) has tremendous potential to address the global shortage of clean drinking water. The Ni₂Cl₂(BTDD) metal–organic framework (MOF) has shown optimal water sorption performance under low relative humidity conditions, but its potentially high production costs, stemming in part from its lengthy multiday synthesis, has hindered widespread implementation. As with most traditional MOF syntheses, the original synthesis of Ni₂Cl₂(BTDD) involves batch reactors that have intrinsic inefficiencies impacting productivity during scale-up. We report a continuous manufacturing process for Ni₂Cl₂(BTDD) that can achieve higher yields, reduced solvent use, and drastically faster crystallization times in comparison to the batch process. Optimization of the synthesis space in the flow reactor as a function of residence time, temperature, and solvent volume yields 50% and 40% reductions in methanol and hydrochloric acid consumption by volume, respectively, with a simultaneous 3-fold increase in productivity (defined in units of kgMOF m–³day–¹). A computational fluid dynamics (CFD) model was developed to quantitate productivity enhancements in the flow reactor based on improved heat-transfer rates, larger surface-area to volume ratios, and effective residence times. This work adds critical facets to the growing body of research suggesting that the synthesis of MOFs in flow reactors offers unique opportunities to reduce production costs.

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Open access
01 Jan 2010-
Abstract: Abstract In this paper, the hydrodynamics and the pressure drop of liquid–liquid slug flow in round microcapillaries are presented. Two liquid–liquid flow systems are considered, viz. water-toluene and ethylene glycol/water-toluene. The slug lengths of the alternating continuous and dispersed phases were measured as a function of the slug velocity (0.03–0.5 m/s), the organic-to-aqueous flow ratio (0.1–4.0), and the microcapillary internal diameter (248 and 498 μm). The pressure drop is modeled as the sum of two contributions: the frictional and the interface pressure drop. Two models are presented, viz. the stagnant film model and the moving film model. Both models account for the presence of a thin liquid film between the dispersed phase slug and the capillary wall. It is found that the film velocity is of negligible influence on the pressure drop. Therefore, the stagnant film model is adequate to accurately predict the liquid–liquid slug flow pressure drop. The influence of inertia and the consequent change of the slug cap curvature are accounted for by modifying Bretherton’s curvature parameter in the interface pressure drop equation. The stagnant film model is in good agreement with experimental data with a mean relative error of less than 7%.

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Topics: Slug flow (76%), Flow coefficient (63%), Pressure drop (62%)

6 Citations


Open accessJournal Article
Abstract: The capture of water vapor at low relative humidity is desirable for producing potable water in desert regions and for heat transfer and storage. Here, we report a mesoporous metal–organic framework that captures 82% water by weight below 30% relative humidity. Under simulated desert conditions, the sorbent would deliver 0.82 gH2O gMOF–1, nearly double the quantity of fresh water compared to the previous best material. The material further demonstrates a cooling capacity of 400 kWh m–3 per cycle, also a record value for a sorbent capable of creating a 20 °C difference between ambient and output temperature. The water uptake in this sorbent is optimized: the pore diameter of our material is above the critical diameter for water capillary action, enabling water uptake at the limit of reversibility.

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Topics: Water vapor (57%), Sorbent (56%), Relative humidity (55%)

2 Citations


Open accessJournal ArticleDOI: 10.1021/ACS.CGD.1C00968
Abstract: A fundamental understanding of the crystallization pathways for metal− organic frameworks (MOFs) allows for exploring the untapped combinatorial space of the organic and inorganic building units, creating possibilities to synthesize highly crystalline frameworks with desired physicochemical properties. In this work, we employ a continuous flow reactor to elucidate the kinetics of crystallization for the Zr-based MOF-808 using time-resolved powder X-ray diffraction measurements. Specifically, we fit the crystallization curves obtained experimentally using the Gualtieri model to determine the rate constants for nucleation (kN) and growth (kG) for different linker concentrations and temperatures. Higher linker concentrations reduce the competitive coordination of the formate ligand (growth modulator) with the secondary building unit, resulting in higher nucleation and growth rates. The activation energies obtained from Arrhenius plots for nucleation (Ea(N)) and growth (Ea(G)) are 64.7 ± 4 and 59.2 ± 5 kJ mol−1, respectively. At constant residence time, temperature, and composition, higher flow velocities increase the advective transport of precursor species to nucleation sites in the slugs resulting in increased crystal growth rates and thus higher average crystal sizes. Variation in the total flow rate from 0.334 to 1.067 mL/min increased the average crystal sizes from ∼105 ± 22 to ∼180 ± 19 nm, with other parameters held constant. We demonstrate that performing crystallization in the flow reactor provides a unique opportunity to tailor MOF crystal sizes. By strictly controlling the temperature, residence time, and mixing parameters, our results showcase the advantages of flow systems for performing rigorous crystallization and structural evolution studies that can be applied for the synthesis of other MOFs with tailored physicochemical properties. ■ INTRODUCTION Metal−organic frameworks (MOFs) are coordination complexes consisting of organic linkers and inorganic polynuclear clusters that form twoand three-dimensional structures. The numerous ways in which the organic and inorganic units can be combined have led to the discovery of thousands of new frameworks with unique properties that can be targeted for use in industrially attractive applications. Zr-based MOFs are particularly important due to their chemical stability, as well as amenability to postsynthetic modification (PSM). MOF-808, first reported by Furukawa et al., is formed from the assembly of a Zr6(μ3-O)4-(μ3-OH)4(CO2)12 (referred to as Zr6-cluster) inorganic secondary building unit and benzene-1,3,5-tricarboxylic acid (H3BTC) organic linkers. 3 The resulting structure features large cavities (diameter of 18.4 Å) and Brunauer− Emmett−Teller (BET) surface areas of ∼2000 m2·g−1. Monocarboxylic ligands, such as formate, acetate, and propionate, are employed as crystal growth modulators in MOF-808 synthesis to regulate crystal size and increase the crystallinity of the framework. Although MOF-808 has been demonstrated for use in a number of industrially relevant applications ranging from catalysis and water harvesting to heavy metal capture and arsenic removal, details pertaining to the kinetics of crystallization or the control of crystal size distributions (CSDs) have not been reported. A thorough understanding of the self-assembly of MOF building units along with the reaction pathways to achieve precise control over the crystallization process would help in optimizing MOF synthesis to yield the desired crystallinity and provide important parameters for synthesis scale-up. Tailored physicochemical properties of Zr-MOFs can be achieved by coordination modulation, using organic ligands with a similar chemical functionality as the linker to compete for coordination sites at the SBU. In the presence of a modulator, nucleation and crystal growth proceed at a reduced rate. The crystallization process requires an equilibrium between crystal formation and dissolution to allow for sufficient reorganization and defect reparation during the early stages of crystal growth. Accordingly, evaluating the amount of modulator, linker concentration, residence time, and temperature in the extent of crystallization is imperative to achieve the desired CSD, crystallinity, and product yields. Received: August 23, 2021 Revised: September 30, 2021 Article pubs.acs.org/crystal © XXXX American Chemical Society A https://doi.org/10.1021/acs.cgd.1c00968 Cryst. Growth Des. XXXX, XXX, XXX−XXX D ow nl oa de d vi a M A SS A C H U SE T T S IN ST O F T E C H N O L O G Y o n O ct ob er 2 1, 2 02 1 at 0 0: 17 :4 5 (U T C ). Se e ht tp s: //p ub s. ac s. or g/ sh ar in gg ui de lin es f or o pt io ns o n ho w to le gi tim at el y sh ar e pu bl is he d ar tic le s.

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2 Citations


Open accessJournal ArticleDOI: 10.1039/D1GC02824C
Sujay Bagi1, Shuai Yuan1, Sergio Rojas-Buzo2, Yang Shao-Horn1  +1 moreInstitutions (2)
05 Nov 2021-Green Chemistry
Abstract: Metal–organic frameworks (MOFs) are promising materials for a wide range of applications given their chemical stability and structural tunability. Most traditional MOF synthesis methods use batch reactors with intrinsic inefficiencies during scale-up that negatively impact process productivity. Here, we report a low-cost and energy-efficient continuous manufacturing process for MOF-808—a Zr-MOF widely studied as a catalyst and adsorbent in industrially important processes—using flow-through reactors that increase process yields and minimize solvent use compared to batch processes. The flow platform allowed us to investigate the influence of several synthesis parameters, including residence time, linker concentration, and volumetric ratio of modulator and solvent on the crystallization process. Under optimal conditions, the N,N-dimethylformamide solvent and formic acid modulator volumetric amounts were decreased by 84% and 67%, respectively, and resulted in an increase in productivity (defined in units of kgMOF m−3 day−1) by two orders of magnitude with similar yields, compared to established batch synthesis methods. A process engineering assessment based on laboratory-scale synthesis routes was performed to compare energy and cost savings for flow and batch workflows, indicating that solvent use was the largest contributor to the overall cost. The methodology presented in this work opens new pathways for critical assessment and optimization of continuous manufacturing routes on a lab-scale environment, which serve as a preliminary step for the transition to more efficient MOF synthesis routes at the industrial scale.

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1 Citations


Open accessJournal ArticleDOI: 10.1021/ACSSUSCHEMENG.1C02146
Abstract: The growing demand for Li-ion batteries (LIBs) has made their postconsumer recycling an imperative need toward the recovery of valuable metals, such as cobalt and nickel. Nevertheless, their recove ...

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Topics: Battery recycling (57%), Cobalt (56%), Nickel (52%)

1 Citations


References
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54 results found


Journal ArticleDOI: 10.1126/SCIENCE.1230444
30 Aug 2013-Science
Abstract: Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

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8,296 Citations



Journal ArticleDOI: 10.1039/B804680H
Abstract: New materials are prerequisite for major breakthrough applications influencing our daily life, and therefore are pivotal for the chemical industry. Metal–organic frameworks (MOFs) constitute an emerging class of materials useful in gas storage, gas purification and separation applications as well as heterogeneous catalysis. They not only offer higher surface areas and the potential for enhanced activity than currently used materials like base metal oxides, but also provide shape/size selectivity which is important both for separations and catalysis. In this critical review an overview of the potential applications of MOFs in the chemical industry is presented. Furthermore, the synthesis and characterization of the materials are briefly discussed from the industrial perspective (88 references).

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1,829 Citations


Open accessJournal ArticleDOI: 10.1002/ANIE.200601554
Helen Song1, Delai Chen1, Rustem F. Ismagilov1Institutions (1)
13 Nov 2006-Angewandte Chemie
Abstract: Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.

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Topics: Microfluidics (51%)

1,618 Citations


Journal ArticleDOI: 10.1016/J.CEJ.2009.10.029
Shaobin Wang1, Yuelian Peng2Institutions (2)
Abstract: Natural zeolites are abundant and low cost resources, which are crystalline hydrated aluminosilicates with a framework structure containing pores occupied by water, alkali and alkaline earth cations Due to their high cation-exchange ability as well as to the molecular sieve properties, natural zeolites have been widely used as adsorbents in separation and purification processes in the past decades In this paper, we review the recent development of natural zeolites as adsorbents in water and wastewater treatment The properties and modification of natural zeolite are discussed Various natural zeolites around the world have shown varying ion-exchange capacity for cations such as ammonium and heavy metal ions Some zeolites also show adsorption of anions and organics from aqueous solution Modification of natural zeolites can be done in several methods such as acid treatment, ion exchange, and surfactant functionalisation, making the modified zeolites achieving higher adsorption capacity for organics and anions

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Topics: Zeolite (55%), Adsorption (52%), Ion exchange (52%)

1,500 Citations