Erratum to: “Application of gas separation to recover biohydrogen produced by Thiocapsa roseopersicina [Desalination 163 (2004) 261–265

Application of gas separation to recover biohydrogen produced by Thiocapsa roseopersicina

Switchable metal–organic frameworks (MOFs) conquer advanced applications in energy storage, sensing, gas separation, catalysis, and biomedicine. They benefit from unique adsorption characteristics and responsive behavior leading to anomalously high separation selectivity and deliverable storage capacity.Nanostructuring provides an effective means to tailor the responsive behavior of switchable MOFs. The characteristic switching pressure depends on critical crystal dimensions.The understanding of critical size effects affecting stimulus-responsive cooperative transformations is in its infancy. Thermodynamic and kinetic factors govern size-dependent switchability. General models explaining size-related changes in responsivity require further methodological development. Advancement of computational and analytical tools is crucial to achieve a deeper understanding of surface, interfacial, and finite size effects. Switchable metal–organic frameworks (MOFs) standt out for potential applications in energy storage, separation, sensing, and catalysis. The understanding of MOF switchability mechanisms has progressed significantly over the past two decades. Nanostructuring is essential for the integration of such materials into thin films, hierarchical composites, and membranes and for biological applications. However, downsizing below critical dimensions causes dramatic changes in the dynamic behavior and responsiveness towards external stimuli. We discuss the most important experimental findings and derive general guidelines and hypotheses of relevance for the impact of crystal size on switchability. Understanding nanostructure thermodynamics and implications for the tailoring of dynamic porous systems requires an interdisciplinary approach, advanced physical characterization techniques, and new modeling strategies to cover a wider range of time and length scales. Switchable metal–organic frameworks (MOFs) standt out for potential applications in energy storage, separation, sensing, and catalysis. The understanding of MOF switchability mechanisms has progressed significantly over the past two decades. Nanostructuring is essential for the integration of such materials into thin films, hierarchical composites, and membranes and for biological applications. However, downsizing below critical dimensions causes dramatic changes in the dynamic behavior and responsiveness towards external stimuli. We discuss the most important experimental findings and derive general guidelines and hypotheses of relevance for the impact of crystal size on switchability. Understanding nanostructure thermodynamics and implications for the tailoring of dynamic porous systems requires an interdisciplinary approach, advanced physical characterization techniques, and new modeling strategies to cover a wider range of time and length scales. MOFs are among the most porous systems, with great potential in diverse applications such as energy storage, separation, air purification, and many more [1.Jiao L. et al.Metal–organic frameworks: structures and functional applications.Mater. Today. 2019; 27: 43-68Crossref Scopus (117) Google Scholar,2.Yuan S. et al.Stable metal–organic frameworks: design, synthesis, and applications.Adv. Mater. 2018; 30: 1704303Crossref PubMed Scopus (667) Google Scholar]. An outstanding feature, compared with other, traditional porous materials, is their ability to transform (switch) between different phases with well-defined crystalline structures triggered by external stimuli, often by guest inclusion [3.Krause S. et al.Chemistry of soft porous crystals–structural dynamics and gas adsorption properties.Angew. Chem. Int. Ed. 2020; 59: 15325-15341Crossref PubMed Scopus (0) Google Scholar,4.Schneemann A. et al.Flexible metal–organic frameworks.Chem. Soc. Rev. 2014; 43: 6062-6096Crossref PubMed Google Scholar]. The latter leads, in some cases, to important improvements in gas separation or storage due to ultrahigh selectivity [5.Li L. et al.Flexible–robust metal–organic framework for efficient removal of propyne from propylene.J. Am. Chem. Soc. 2017; 139: 7733-7736Crossref PubMed Scopus (136) Google Scholar] or high deliverable capacity [6.Mason J.A. et al.Methane storage in flexible metal–organic frameworks with intrinsic thermal management.Nature. 2015; 527: 357-361Crossref PubMed Scopus (491) Google Scholar]. The terms 'flexible MOF', 'soft porous crystals', and 'switchable MOF' are used synonymously [7.Horike S. et al.Soft porous crystals.Nat. Chem. 2009; 1: 695Crossref PubMed Scopus (1544) Google Scholar,8.Evans J.D. et al.Four-dimensional metal–organic frameworks.Nat. Commun. 2020; 11: 2690Crossref PubMed Scopus (12) Google Scholar]. An important aspect indicated by the term 'switchability' is the stepwise (first order) character of the structural transition between two phases (bistability). Recently, even multistable systems have emerged, leading to remarkable recognition effects [9.Katsoulidis A.P. et al.Chemical control of structure and guest uptake by a conformationally mobile porous material.Nature. 2019; 565: 213-217Crossref PubMed Scopus (70) Google Scholar,10.Ehrling S. et al.Adaptive response of a metal–organic framework through reversible disorder–disorder transitions.ChemRxiv. 2020; (Published online May 19, 2020. https://doi.org/10.26434/chemrxiv.12326165.v1)Google Scholar]. These phase transitions induced by external stimuli (e.g., changes in temperature, external pressure, gas pressure, vapor pressure, or electromagnetic radiation) are associated with a latent heat of transformation, L, governing the energetics of the bulk phase transition. An activation barrier (EA or ΔGǂ) governs the kinetics and potential windows for metastable states. Nucleation (for nucleation theory see Glossary and see supplemental information online for additional Glossary terms) of the new solid phase is an important characteristic of the solid–solid phase transition. Nevertheless, the fluid kinetics of adsorption and, potentially, fluid nucleation kinetics may also play a role. The integration of switchable MOFs into applications frequently requires downsizing to the submicron or even nanoscale (Figure 1) (e.g., in membranes [11.Rodenas T. et al.Metal–organic framework nanosheets in polymer composite materials for gas separation.Nat. Mater. 2015; 14: 48-55Crossref PubMed Scopus (1099) Google Scholar, 12.Hou Q. et al.Balancing the grain boundary structure and the framework flexibility through bimetallic metal–organic framework (MOF) membranes for gas separation.J. Am. Chem. 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Finite submicron dimensions and morphology affect the switchability of dynamic MOFs, resulting in pronounced changes in gas adsorption isotherms with severe implications for separation performance (Figure 2) [16.Linder-Patton O.M. et al.Particle size effects in the kinetic trapping of a structurally-locked form of a flexible MOF.CrystEngComm. 2016; 18: 4172-4179Crossref Google Scholar, 17.Tanaka D. et al.Rapid preparation of flexible porous coordination polymer nanocrystals with accelerated guest adsorption kinetics.Nat. Chem. 2010; 2: 410-416Crossref PubMed Scopus (266) Google Scholar, 18.Hijikata Y. et al.Differences of crystal structure and dynamics between a soft porous nanocrystal and a bulk crystal.Chem. 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(A) Gating (purple, macro) and its suppression by downscaling leading to a type I isotherm of rigid crystal (orange, nano), (B) breathing (purple, macro) and suppression (orange, nano), (C) negative gas adsorption (NGA) (purple, macro) and rigidification (orange, nano), (D) gate-shift hysteresis and widening, and (E) gate-opening emergence.View Large Image Figure ViewerDownload (PPT) The purple lines show the isotherm of the macrosized bulk crystals; the orange line is the result of downsizing to the submicron or nanoregime. (A) Gating (purple, macro) and its suppression by downscaling leading to a type I isotherm of rigid crystal (orange, nano), (B) breathing (purple, macro) and suppression (orange, nano), (C) negative gas adsorption (NGA) (purple, macro) and rigidification (orange, nano), (D) gate-shift hysteresis and widening, and (E) gate-opening emergence. In the following sections, we identify key experimental findings in this field and relate these to existing theories of size-dependent phase transitions. We outline the most important factors relevant to size-dependent switchability and derive a comprehensive scenario of relevant aspects. From this, we deduce future directions for simulation and experimental studies to advance the understanding of nucleation, interfacial effects, and surface layers influencing switchability. Nanostructures are essential for many applications (Figure 1 and Box 1). The increased outer active surface and mass transport in nanocrystals is advantageous for catalytic applications [38.Herbst A. et al.Brønsted instead of Lewis acidity in functionalized MIL-101Cr MOFs for efficient heterogeneous (nano-MOF) catalysis in the condensation reaction of aldehydes with alcohols.Inorg. 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Rev. 2009; 38: 1380-1399Crossref PubMed Scopus (1226) Google Scholar, 99.Bureekaew S. et al.Orbital directing effects in copper and zinc based paddle-wheel metal organic frameworks: the origin of flexibility.J. Mater. Chem. 2012; 22: 10249-10254Crossref Scopus (44) Google Scholar, 100.Evans J.D. et al.Origins of negative gas adsorption.Chem. 2016; 1: 873-886Abstract Full Text Full Text PDF Scopus (0) Google Scholar, 101.Sarkisov L. et al.On the flexibility of metal–organic frameworks.J. Am. Chem. Soc. 2014; 136: 2228-2231Crossref PubMed Scopus (143) Google Scholar, 102.Krause S. et al.A pressure-amplifying framework material with negative gas adsorption transitions.Nature. 2016; 532: 348Crossref PubMed Google Scholar, 103.Carrington E.J. et al.Solvent-switchable continuous-breathing behaviour in a diamondoid metal–organic framework and its influence on CO2 versus CH4 selectivity.Nat. Chem. 2017; 9: 882Crossref PubMed Scopus (158) Google Scholar, 104.Fairen-Jimenez D. et al.Opening the gate: framework flexibility in ZIF-8 explored by experiments and simulations.J. Am. Chem. Soc. 2011; 133: 8900-8902Crossref PubMed Scopus (639) Google Scholar]. Energy-efficient separation processes are investigated in academia [105.Du Y. et al.New high-and low-temperature phase changes of ZIF-7: elucidation and prediction of the thermodynamics of transitions.J. Am. Chem. Soc. 2015; 137: 13603-13611Crossref PubMed Scopus (30) Google Scholar] and industry [106.Adil K. et al.Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship.Chem. Soc. Rev. 2017; 46: 3402-3430Crossref PubMed Google Scholar,107.Sholl D.S. Lively R.P. Seven chemical separations to change the world.Nature. 2016; 532: 435-437Crossref PubMed Scopus (932) Google Scholar]. The majority of MOFs are rigid compounds. Switchable MOFs with ultrahigh selectivity are receiving increasing attention for challenging separations [108.Yu J. et al.CO2 capture and separations using MOFs: computational and experimental studies.Chem. Rev. 2017; 117: 9674-9754Crossref PubMed Scopus (462) Google Scholar, 109.Bao Z. et al.Potential of microporous metal–organic frameworks for separation of hydrocarbon mixtures.Energy Environ. Sci. 2016; 9: 3612-3641Crossref Google Scholar, 110.Bobbitt N.S. et al.Metal–organic frameworks for the removal of toxic and chemical Soc. Rev. 2017; 46: PubMed Google Scholar]. to external stimuli changes in The physical response efficient for N. et by structural of guest in a flexible porous coordination Mater. 2011; 10: PubMed Scopus Google Scholar, X. et al.Metal–organic frameworks for Mater. 2018; 30: PubMed Scopus Google Scholar, A. et breathing mechanisms in flexible metal–organic frameworks: impact of the metal Mater. Chem. 2018; 30: Scopus Google Scholar, P. et composite as Appl. Mater. Interfaces. 2017; 9: PubMed Scopus Google Scholar, P. et films for at high Chem. Eng. 2019; 7: Scopus Google Scholar, et al.A flexible for switchable and temperature Mater. Chem. 2018; 30: Scopus Google Scholar]. applications selective catalysis et of catalytic the of a flexible coordination Eur. J. 2012; 18: PubMed Scopus Google S. et al.Flexible metal-organic frameworks as switchable Chem. Int. Ed. 2016; PubMed Scopus Google materials et al.A flexible metal–organic framework with a high density of for Energy. 2017; 2: Scopus Google and CO2 separation E.J. et al.Solvent-switchable continuous-breathing behaviour in a diamondoid metal–organic framework and its influence on CO2 versus CH4 selectivity.Nat. Chem. 2017; 9: 882Crossref PubMed Scopus (158) Google et CO2/CH4 selectivity through reversible guest in the flexible metal–organic framework Am. Chem. Soc. 2018; PubMed Scopus (0) Google Scholar]. MOFs, featuring repeatable structural transformations, are attractive for research and many important applications [98.Férey G. Serre C. Large breathing effects in three-dimensional porous hybrid matter: facts, analyses, rules and consequences.Chem. Soc. Rev. 2009; 38: 1380-1399Crossref PubMed Scopus (1226) Google Scholar, 99.Bureekaew S. et al.Orbital directing effects in copper and zinc based paddle-wheel metal organic frameworks: the origin of flexibility.J. Mater. Chem. 2012; 22: 10249-10254Crossref Scopus (44) Google Scholar, 100.Evans J.D. et al.Origins of negative gas adsorption.Chem. 2016; 1: 873-886Abstract Full Text Full Text PDF Scopus (0) Google Scholar, 101.Sarkisov L. et al.On the flexibility of metal–organic frameworks.J. Am. Chem. Soc. 2014; 136: 2228-2231Crossref PubMed Scopus (143) Google Scholar, 102.Krause S. et al.A pressure-amplifying framework material with negative gas adsorption transitions.Nature. 2016; 532: 348Crossref PubMed Google Scholar, 103.Carrington E.J. et al.Solvent-switchable continuous-breathing behaviour in a diamondoid metal–organic framework and its influence on CO2 versus CH4 selectivity.Nat. Chem. 2017; 9: 882Crossref PubMed Scopus (158) Google Scholar, 104.Fairen-Jimenez D. et al.Opening the gate: framework flexibility in ZIF-8 explored by experiments and simulations.J. Am. Chem. Soc. 2011; 133: 8900-8902Crossref PubMed Scopus (639) Google Scholar]. Energy-efficient separation processes are investigated in academia [105.Du Y. et al.New high-and low-temperature phase changes of ZIF-7: elucidation and prediction of the thermodynamics of transitions.J. Am. Chem. Soc. 2015; 137: 13603-13611Crossref PubMed Scopus (30) Google Scholar] and industry [106.Adil K. et al.Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship.Chem. Soc. Rev. 2017; 46: 3402-3430Crossref PubMed Google Scholar,107.Sholl D.S. Lively R.P. Seven chemical separations to change the world.Nature. 2016; 532: 435-437Crossref PubMed Scopus (932) Google Scholar]. The majority of MOFs are rigid compounds. Switchable MOFs with ultrahigh selectivity are receiving increasing attention for challenging separations [108.Yu J. et al.CO2 capture and separations using MOFs: computational and experimental studies.Chem. Rev. 2017; 117: 9674-9754Crossref PubMed Scopus (462) Google Scholar, 109.Bao Z. et al.Potential of microporous metal–organic frameworks for separation of hydrocarbon mixtures.Energy Environ. Sci. 2016; 9: 3612-3641Crossref Google Scholar, 110.Bobbitt N.S. et al.Metal–organic frameworks for the removal of toxic and chemical Soc. Rev. 2017; 46: PubMed Google Scholar]. to external stimuli changes in The physical response efficient for N. et by structural of guest in a flexible porous coordination Mater. 2011; 10: PubMed Scopus Google Scholar, X. et al.Metal–organic frameworks for Mater. 2018; 30: PubMed Scopus Google Scholar, A. et breathing mechanisms in flexible metal–organic frameworks: impact of the metal Mater. Chem. 2018; 30: Scopus Google Scholar, P. et composite as Appl. Mater. Interfaces. 2017; 9: PubMed Scopus Google Scholar, P. et films for at high Chem. Eng. 2019; 7: Scopus Google Scholar, et al.A flexible for switchable and temperature Mater. Chem. 2018; 30: Scopus Google Scholar]. applications selective catalysis et of catalytic the of a flexible coordination Eur. J. 2012; 18: PubMed Scopus Google S. et al.Flexible metal-organic frameworks as switchable Chem. Int. Ed. 2016; PubMed Scopus Google materials et al.A flexible metal–organic framework with a high density of for Energy. 2017; 2: Scopus Google and CO2 separation E.J. et al.Solvent-switchable continuous-breathing behaviour in a diamondoid metal–organic framework and its influence on CO2 versus CH4 selectivity.Nat. Chem. 2017; 9: 882Crossref PubMed Scopus (158) Google et CO2/CH4 selectivity through reversible guest in the flexible metal–organic framework Am. Chem. Soc. 2018; PubMed Scopus (0) Google Scholar]. MOFs are in many applications, is essential to the

14 - Fluoropolymer nanocomposite membranes for gas separation applications

Polymers of intrinsic microporosity (PIMs), with an interconnected microporous network, high surface area, and structural diversity, have attracted great interest in developing diverse materials for various applications in the fields of environmental remediation, gas and liquid separation, sensors, and energy. Solution-processable PIMs can be transformed into various robust functional materials, including films, membranes, coatings, and fibers, that can be applied to address different industrial challenges. Since the first PIM synthesis, great strides have been made in expanding the structural diversity of PIMs by designing fine-tuned PIMs for various applications. This review provides a general overview of PIMs, from their synthesis to their involvement in state-of-the-art applications such as water and air filtration, gas and liquid separation, catalysis, sensing, and energy applications, during the last decade. Several PIMs have exhibited outstanding performance in oil adsorption, gas separation, and catalysis. In this context, PIMs’ functionality and porosity are key parameters that must be controlled to tailor PIMs for broader applications. Overall, this review provides a comprehensive overview of PIMs from chemistry to applications and highlights the challenges and prospects of the next generation of PIM-based functional materials that will open new avenues for adsorption, gas separation, and filtration applications.

Nanospace within metal–organic frameworks for gas storage and separation

Reverse-selective polymeric membranes for gas separations

A two-dimensional photoluminescent cadmium(II) coordination polymer containing a new coordination mode of pyridine-2,3-dicarboxylate: Synthesis, structure and molecular simulations for gas storage and separation applications

A high-throughput gas adsorption apparatus is presented for the evaluation of adsorbents of interest in gas storage and separation applications. This instrument is capable of measuring complete adsorption isotherms up to 40 bar on six samples in parallel using as little as 60 mg of material. Multiple adsorption cycles can be carried out and four gases can be used sequentially, giving as many as 24 adsorption isotherms in 24 h. The apparatus has been used to investigate the effect of metal center (MIL-100) and functional groups (CAU-10) on the adsorption of N(2), CO(2), and light hydrocarbons on MOFs. This demonstrates how it can serve to evaluate sample quality and adsorption reversibility, to determine optimum activation conditions and to estimate separation properties. As such it is a useful tool for the screening of novel adsorbents for different applications in gas separation, providing significant time savings in identifying potentially interesting materials.

The increase in global energy demand, the scarcity of fossil fuels resources, climate change and global warming are undeniable realities. In this energy context, the implementation of concrete measures in favor of greater energy efficiency systems becomes urgent. Among these systems, the integration of environmental friendly, low energy adsorption technologies is gaining more interest in many chemical, residential and industrial applications such as adsorption refrigeration systems, quality treatment and energy storage processes. Pressure swing adsorption and temperature swing adsorption are among the promising techniques for CO2 capturing and separation from exhaust gases. In this study, corrected adsorption rates of CO2 onto activated carbon powder were investigated using computational fluid dynamics simulation. The modified linear driving force (mLDF) model was used as the adsorption kinetics equation by fitting of experimental data with isothermal assumption. Then the adsorbent layer temperature was estimated with CFD simulation which allowed to adjust the diffusion time constants for accurate performance investigation of CO2 adsorption cooling, storage and separation applications.

Covalent organic frameworks (COFs) are crystalline porous polymers constructed from organic building blocks into ordered two- or three-dimensional networks through dynamic covalent bonds. Attributed to their high porosity, well-defined structure, tailored functionality and excellent chemical stability, COFs have been considered ideal sorbents for various separation applications. The synthesis of COFs mainly employs the solvothermal method, which usually requires organic solvents in sealed Pyrex tubes, resulting in unscalable powdery products and environmental pollution that seriously limits their practical applications. Herein, our protocol focuses on an emerging synthesis method for COFs based on organic flux synthesis without adding solvents. The generality of this synthesis protocol has been applied in preparing various types of COFs, including olefin-linked, imide-linked, Schiff-based COFs on both gram and kilogram scales. Furthermore, organic flux synthesis avoids the disadvantages of solvothermal synthesis and enhances the crystallization and porosity of COFs. Typically, COF synthesis takes 3-5 d to complete, and subsequent washing procedures leading to pure COFs need 1 d. The procedure for kilogram-scale production of COFs with commercially available monomers is also provided. The resulting COFs are suitable for separation applications, particularly as adsorbent materials for industrial gas separation and water treatment applications. The protocol is suited for users with prior expertise in the synthesis of inorganic materials and porous organic materials.

Metal–organic framework nanosheets (MONs) have recently emerged as a distinct class of 2D materials with programmable structures that make them useful in diverse applications. In this review, the breadth of applications that have so far been investigated are surveyed, thanks to the distinct combination of properties afforded by MONs. How: 1) The high surface areas and readily accessible active sites of MONs mean they have been exploited for a variety of heterogeneous, photo‐, and electro‐catalytic applications; 2) their diverse surface chemistry and wide range of optical and electronic responses have been harnessed for the sensing of small molecules, biological molecules, and ions; 3) MONs tunable optoelectronic properties and nanoscopic dimensions have enabled them to be harnessed in light harvesting and emission, energy storage, and other electronic devices; 4) the anisotropic structure and porous nature of MONs mean they have shown great promise in a variety of gas separation and water purification applications; are discussed. The aim is to draw links between the uses of MONs in these different applications in order to highlight the common opportunities and challenges presented by this promising class of nanomaterials.

11 - Applications of MXenes in gas separation and energy storage

Metal-organic frameworks (MOFs) have emerged as versatile materials with applications in gas separation, catalysis, and energy storage due to their high porosity and tunable structures. However, traditional synthesis methods often involve toxic solvents and high energy inputs, limiting scalability and environmental sustainability. This review explores green synthesis strategies for robust MOFs, focusing on water-based hydrothermal and ambient temperature approaches that enhance stability and performance. Key examples include aluminum-based MOFs for water adsorption and zirconium-based frameworks for gas purification, demonstrating high yields, stability in harsh conditions, and efficient applications in heat allocation and ethylene separation. These methods align with the principles of sustainable chemistry, paving the way for their industrial adoption.

The characteristics and preparation methods of zeolite-based adsorbents and membranes were reviewed and their applications in gas separation and purification were introduced according to classification. The effects of framework structure, equilibrium cations and pore size of zeolites as well as temperature and pressure of the system on gas adsorption and separation were discussed, and the separation mechanisms were also summarized. The main defects and improved methods of zeolite-based adsorbents and membranes were briefly described, and their future trend for gas separation and purification was finally prospected.

Nanostructured membranes containing UiO-66 (Zr) and MIL-101 (Cr) for O2/N2 and CO2/N2 separation