Covalent postsynthetic modification (PSM) of metal-organic frameworks (MOFs) has attracted much attention due to the possibility of tailoring the properties of these porous materials. Schiff-base condensation between an amine and an aldehyde is one of the most common reactions in the PSM of MOFs. Here, we report the use of the spray drying technique to perform this class of organic reactions, either between discrete organic molecules or on the pore surfaces of MOFs, in a very fast (1-2 s) and continuous way. Using spray drying, we show the PSM of two MOFs, the amine-terminated UiO-66-NH and the aldehyde-terminated ZIF-90, achieving conversion efficiencies up to 20 and 42%, respectively. Moreover, we demonstrate that it can also be used to postsynthetically cross-link the aldehyde groups of ZIF-90 using a diamine molecule with a conversion efficiency of 70%.

The exceptional porosity of Metal-Organic Frameworks (MOFs) could be harnessed for countless practical applications. However, one of the challenges currently precluding the industrial exploitation of these materials is a lack of green methods for their synthesis. Since green synthetic methods obviate the use of organic solvents, they are expected to reduce the production costs, safety hazards and environmental impact typically associated with MOF fabrication. Herein we describe the stepwise optimisation of reaction parameters (pH, reagent concentrations and reaction time) for the room temperature, water-based synthesis of several members of the CPO-27/MOF-74-M series of MOFs, including ones made from Mg(II), Ni(II), Co(II) and Zn(II) ions. Using this method, we built MOFs with excellent BET surface areas and unprecedented Space-Time Yields (STYs). Employing this approach, we have synthesised CPO-27-M MOFs with record BET surface areas, including 1279 m g (CPO-27-Zn), 1351 m g (CPO-27-Ni), 1572 m g (CPO-27-Co), and 1603 m g (CPO-27-Mg). We anticipate that our method could be applied to produce CPO-27-Ni, -Mg, -Co and -Zn with STYs of 44 Kg m day, 191 Kg m day, 1462 Kg m day and a record 18720 Kg m day, respectively.

A novel spray-drying continuous-flow method allows the synthesis of high-nuclearity MOFs as well as multivariate MOFs in the form of compact microspherical superstructures (beads) in good yields and high porosity.

Herein, we describe a new class of porous composites comprising metal–organic framework (MOF) crystals confined in single spherical matrices made of packed covalent‐organic framework (COF) nanocrystals. These MOF@COF composites are synthesized through a two‐step method of spray‐drying and subsequent amorphous (imine‐based polymer)‐to‐crystalline (imine‐based COF) transformation. This transformation around the MOF crystals generates micro‐ and mesopores at the MOF/COF interface that provide far superior porosity compared to that of the constituent MOF and COF components added together. We report that water sorption in these new pores occurs within the same pressure window as in the COF pores. Our new MOF@COF composites, with their additional pores at the MOF/COF interface, should have implications for the development of new composites.

Metal-organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV-vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66-NH, ZIF-67, CPO-27-M (M = Zn, Ni, and Mg), Fe-MIL-101-NH, and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs).

Adsorptive heat transformation (AHT) systems such as adsorption thermal batteries and chillers can provide space heating and cooling in a more environmental friendly way.However, their use is still hindered by their relatively poor performances and large sizes due to the limited properties of solid adsorbents. Here, we report the spray-drying continuous-flow synthesis of a new type of solid adsorbents that results from combining metal-organic frameworks (MOFs), such as UiO-66, and hygroscopic salts, such as CaCl2. These adsorbents, commonly named as composite salt in porous matrix (CSPM) "This is the peer reviewed version of the following article: Luis Garzón-Tovar, Javier Pérez-Carvajal, Inhar Imaz. Composite Salt in Porous Metal-Organic Frameworks for Adsorption Heat Transformation, Advanced Functional Materials, 27(21): 1606424, which has been published in final form https://doi.org/10.1002/adfm.201606424. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions." 2 materials, are packed in the form of spherical superstructures/beads. In terms of water sorption properties, these composites allow improving the water uptake capabilities of MOFs while preventing their dissolution in the water adsorbed; a common characteristic of these salts due to the deliquescence effect. We anticipate that these MOF-based CSPMs, in which the percentage of salt can be tuned, are promising candidates for adsorption thermal batteries and chillers. In the first application, we show that a CSPM made of UiO-66 and CaCl2 (38 % w/w) exhibits a heat storage capacity of 367 kJ kg -1 .For adsorption chillers, we demonstrate that a second CSPM made of UiO-66 and CaCl2 (53 % w/w) shows a specific cooling power of 631 W kg -1 and a coefficient of performance of 0.83, comparable to the best solid adsorbents reported so far. INTRODUCTIONThe anthropogenic greenhouse gas emissions related to the demand of electrical energy by traditional space heating and air conditioning processes have increased over the past decade. [1] To solve this problem, several initiatives have been proposed to replace the traditional vapor compression devices by more environmentally friendly adsorptive heat transformation (AHT) systems, such as adsorption chillers, heat pumps and thermal batteries. [2] These AHT systems are based on an adsorption-desorption cycle of a working fluid, where useful heat is released during the adsorption step and cold is produced during the evaporation of the working fluid. The main advantages of these systems are (i) the possibility to use low thermal energy sources (e.g. solar and waste heat) for regeneration and driving energy; and (ii) that water can be used as the working fluid. [3]

Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein we report the complementary adsorption capacities of metal-organic frameworks (MOFs; here, UiO-66 and UiO-66(SH)2) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II) and Hg(II). We further show that these microbeads can be used as packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly-polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spraydrying technique to simultaneously incorporate two types of iNPs (CeO2 and Fe3O4) into UiO-66(SH)2, obtaining CeO2/Fe3O4@UiO-66-(SH)2 microbeads that adsorb heavy metals and are magnetically responsive.water by a magnet. Given their ready formation and tunability, we are confident that such iNP@MOF-Beads will prove utile in future water-purification applications.

We report the synthesis of a highly active and stable metal‐organic framework derived Ni‐based catalyst for the photothermal reduction of CO2 to CH4. Through the controlled pyrolysis of MOF‐74 (Ni), the nature of the carbonaceous species and therefore photothermal performance can be tuned. CH4 production rates of 488 mmol g−1 h−1 under UV‐visible‐IR irradiation are achieved when the catalyst is prepared under optimized conditions. No particle aggregation or significant loss of activity were observed after ten consecutive reaction cycles or more than 12 hours under continuous flow configuration. Finally, as a proof‐of‐concept, we performed an outdoor experiment under ambient solar irradiation, demonstrating the potential of our catalyst to reduce CO2 to CH4 using only solar energy.