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Global energy demand is met in large part, by burning of fossil fuels, which is causing global warming. Mixed matrix membranes (MMMs) with metal organic frameworks (MOFs) as fillers are an interesting alternative for capturing post combustion CO2 which would make the energy sector sustainable. This research is focused on the synthesis of MOF ZIF‐94 from the recycling of its mother liquors and the incorporation of synthesized MOF into a Pebax MH 1657 for MMM fabrication. The pH and the temperature of ZIF‐94 synthesis are modified and monitored and this results in various nanoparticle diameters (average particle size in the range of 41 ± 8–180 ± 73 nm). Incorporation of ZIF‐94 significantly improves the performance of the bare Pebax MH 1657 membrane. The maximum CO2/N2 selectivity and CO2 permeability are obtained for 10 wt% ZIF‐94 loading in 9 wt% (polymer concentration in 70/30 (v/v) ethanol/water solution) Pebax MH 1657 matrix being 36 ± 7 (71% increment compared to bare membrane) and 137 ± 31 Barrer (80% improvement), respectively. [ABSTRACT FROM AUTHOR]

Viruses affect humanity causing deaths and economic problems all over the world. Metal‐organic frameworks (MOFs) and zeolites are nanoporous compounds that can be tailor‐synthetized to specific applications to detect and control virus infections. Three main applications are found for these materials towards viruses: biosensors, barriers and biocomposites. Biosensors based on MOFs and zeolites possess a high selectivity in fluorescence assays to detect virus genetic material. Barriers based on modified zeolites are tools to remove or concentrate viruses in water sources, besides zeolites powders can be added to other materials like fabrics and plastics to create or enhance physical barriers to viruses. Biocomposites are materials that are composed of at least one natural resource, constituting a new technology, which can be a strategy to deliver drugs in medicine and protect biological substances against denaturing process, under this concept it is possible to create vaccine‐based viral‐like particles. [ABSTRACT FROM AUTHOR]

In this work, alveolar‐like microfluidic devices are studied with a horizontal membrane arrangement that demonstrate a great potential as small‐scale blood oxygenator. The design criteria for the fabricated devices are to maximize the oxygen saturation level and minimize liquid chamber volume while ensuring the physiological blood flow in order to avoid thrombus formation and channel blockage during operation. The liquid chamber architecture is iteratively modified upon analysis of the fluid dynamics by computer modeling. Accordingly, two alveolar type architectures are fabricated, Alveolar Design 1 (AD1) and Alveolar Design 2 (AD2), and evaluated for oxygenation of sheep blood. The attained O2 transfer rate at 1 mL min−1 of blood flow rate for both devices is rather similar: 123 and 127 mL min−1 m−2 for AD1 and AD2 microfluidic devices, respectively. Among the studied, AD2 type geometry would lead to the lowest pressure drop and shear stress value upon implementation in a scaled microfluidic artificial lung (μAL) to satisfy oxygenation requirements of a 2.0 kg neonate. [ABSTRACT FROM AUTHOR]

A novel synthesis process of ZIF-94 (also known as SIM-1) is developed for particle size tuning, using either NaOH or NH4OH as a deprotonator. ZIF-94 originate from MOFs and have several advantages over traditional porous materials, in terms of their chemistry, structure and applications as catalysts, adsorbents, biocides and membrane materials. The existing synthesis process for ZIF-94 at a scale-up level produces particles of approximately 250 nm in size; an even smaller size is expected to result in an even better gas separation performance and catalytic activity. In this study, it was found that NaOH results in ZIF-94 particles with well-defined crystal structures, while in the case of NH4OH, the particles agglomerate to produce random shaped bigger particles. The optimum base to metal ratio was found to be 2 : 1 (NaOH : Zn), which shows a compromise between the particle size (114 ± 3 nm) and BET specific surface area (254 ± 4 m2 g−1). Furthermore, the synthesized nanoparticles underwent thorough characterization by XRD, TGA, N2 adsorption and electron microscopy revealing the lowest SEM average particle size of 84 ± 3 nm. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) have recently attracted considerable research interest in several fields from coordination chemistry and materials science to engineering and medicine not only due to energy and environmental issues but also due to the need for new paradigms of efficiency and sustainability according to the requirements of the 21st century global society. Because of their crystalline and organic–inorganic nature, they are able to crystallize constituting intergrown architectures ductile enough to be patterned, with the use of appropriate techniques, as nano- and micro-devices with multiple applications. This perspective comprehensively summarizes the recent state of the art in the use of top-down and bottom-up methodologies to create MOF structures with a defined pattern at the nano- and micro-scale. [ABSTRACT FROM AUTHOR]

The inner and outer surfaces of a porous hollow fiber polysulfone support are compared as substrates for the synthesis of polyamide thin‐film composite (TFC) membranes by interfacial polymerization. While both surfaces have pores common of microfiltration membranes, the inner surface has a larger pore diameter than the outer surface (2,700 nm compared to 950 nm). The inner TFC membrane showed higher water nanofiltration permeance than the outer (2.20 ± 0.17 compared to 0.13 ± 0.03 L m−2 hr−1 bar−1). This was due to the influence of the porosity and roughness, which were different on both support surfaces. These membranes are interesting because they were synthesized in a hollow fiber support with a high membrane area per volume unit (~6,900 m2/m3) and the substrate used was commercial, which means that the TFC membrane obtained is suitable for industrial application. A mathematical simulation of the nanofiltration run with COMSOL Multiphysics 5.3 software confirmed the experimental trends observed. [ABSTRACT FROM AUTHOR]

Enzymatic membrane (EM) is a tool allowing to simultaneously upgrade enzymatic catalysis and membrane separation processes. However, their commercial use is often restricted by a trade-off between catalytic and mass transfer properties of the system. Herein, we report a new approach to the design of enzymatic membrane reactors (EMRs) - aimed to find the optimal balance between biocatalytic activity, water permeability, and enzyme loading; where we used co-deposited polyallylamine hydrochloride/polydopamine (PAH/PDA) membrane coatings as a tool to control the overall reactor performance. First, we demonstrate that tailoring the PAH/PDA coating chemistry can be more effective for promotion of total biocatalytic activity of EM with immobilized alcohol dehydrogenase (ADH) than increasing the amount of immobilized enzyme on a membrane support. Then, we show how the PAH/PDA ratio (0, 1:10, 1:2, 5:2), modification time (0.25, 1, 4, 16 h) and ionic strength (0.1–1.0 M NaCl) affect morphology of the membrane coating and alter the mechanisms of ADH-support interactions. Lastly, we illustrate the versatility of the PAH/PDA-coated membranes for application in other enzymatic systems on the example of glycerol dehydrogenase (GDH) and evaluate the performance of two EMRs as a function of applied pressure (1–3 bar). The final values of biocatalytic activities 25.4 ± 4.0 and 3.5 ± 0.3 mU/cm2 (which correspond to 140 ± 22 and 67 ± 5% immobilization efficiencies) for immobilized ADH and GDH, respectively, demonstrate that PAH/PDA-coated membranes not only can be used for simultaneous reaction and recovery of the biocatalyst, but also for enhancement of enzymatic activity - due to opportunity of reaction rate control in the membrane reactor. [Display omitted] • New membrane modification method for preparation of enzymatic membranes was proposed. • PAH/PDA coatings helped to retain both high biocatalytic activity and high water permeability. • Effect of co-deposition time, PAH/PDA ratio, and ionic strength on coating chemistry was estimated. • Enzymatic membrane allowed to exceed specific activity of immobilized ADH compared to free enzyme. [ABSTRACT FROM AUTHOR]

The novel concept of a microfluidic chip with an integrated three-dimensional fractal geometry with nanopores, acting as a gas transport membrane, is presented. The method of engineering the 3D fractal structure is based on a combination of anisotropic etching of silicon and corner lithography. The permeation of oxygen and carbon dioxide through the fractal membrane is measured and validated theoretically. The results show high permeation flux due to low resistance to mass transfer because of the hierarchical branched structure of the fractals, and the high number of the apertures. This approach offers an advantage of high surface to volume ratio and pores in the range of nanometers. The obtained results show that the gas permeation through the nanonozzles in the form of fractal geometry is remarkably enhanced in comparison to the commonly-used polydimethylsiloxane (PDMS) densemembrane. The developed chip is envisioned as an interesting alternative for gas-liquid contactors that require harsh conditions, such as microreactors or microdevices, for energy applications. [ABSTRACT FROM AUTHOR]

Highly hydrophilic inorganic material graphene oxide (GO) was successfully prepared and incorporated into a cross-linked poly(vinyl alcohol) (PVA) matrix. The obtained mixed matrix membranes (MMMs) have been used for the dehydration of ethanol (10:90% water-ethanol) by pervaporation (PV), monitoring their performance in terms of total permeate flux, partial components fluxes, as well as their separation factor. The effect of filler was analyzed by doubling the GO content (at 0.5, 1.0, and 2.0 wt%) in the MMMs. A complete analysis of the operating temperature (between 40 and 70 °C) was carried out by means of Arrhenius relationship. Moreover, the membranes were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), measurements of degree of swelling (uptake), water contact angle (CA) and mechanical properties. At 40 °C, the best performance was provided by the MMMs containing 1 wt% GO, showing a separation factor of 263 and a permeate flux of about 0.137 kg m−2 h−1 (in which 0.133 kg m−2 h−1 corresponds to water). This represents a 75% enhancement of the original permeation rate of pristine cross-linked PVA membranes. Taking into account the promising results, it is likely that these MMMs will provide featured benefits in green processes, e.g. ethanol purification by means of less-energy consumption. Highly hydrophilic inorganic material graphene oxide was successfully prepared and incorporated into a cross-linked poly(vinyl alcohol) (PVA) matrix for ethanol dehydration. Image 1 • Hydrophilic graphene oxide (GO) was successfully incorporated (at 0.5, 1.0, and 2.0 wt%) into PVA matrix. • The obtained mixed matrix membranes (MMMs) were used for the ethanol dehydration by pervaporation (PV). • Complete analysis of the temperature (between 40 and 70 °C) was carried out by Arrhenius relationship. • The best performance with 1 wt% GO showed a separation factor of 263 and a PV flux of 0.14 kg m−2 h−1. • An enhancement of 75% for the pristine cross-linked PVA permeation rate was achieved. [ABSTRACT FROM AUTHOR]

Polybenzimidazole (PBI) is a promising and suitable membrane polymer for the separation of the H 2 /CO 2 pre-combustion gas mixture due to its high performance in terms of chemical and thermal stability and intrinsic H 2 /CO 2 selectivity. However, there is a lack of long-term separation studies with this polymer, particularly when it is conformed as hollow fibre membrane. This work reports the continuous measurement of the H 2 /CO 2 separation properties of PBI hollow fibres, prepared as mixed matrix membranes with metal-organic framework (MOF) ZIF-8 as filler. To enhance the scope of the experimental approach, ZIF-8 was synthesized from the transformation of ZIF-L upon up-scaling the MOF synthesis into a 1 kg batch. The effects of membrane healing with poly(dimethylsiloxane), to avoid cracks and non-selective gaps, and operation conditions (use of sweep gas or not) were also examined at 200°C during approximately 51 days. In these conditions, for all the membrane samples studied, the H 2 permeance was in the 22-47 GPU range corresponding to 22-32 H 2 /CO 2 selectivity values. Finally, this work continues our previous report on this type of application (Etxeberria-Benavides et al . 2020 Sep. Purif. Technol. 237 , 116347 (doi:10.1016/j.seppur.2019.116347)) with important novelties dealing with the use of ZIF-8 for the mixed matrix membrane coming from a green methodology, the long-term gas separation testing for more than 50 days and the study on the membrane operation under more realistic conditions (e.g. without the use of sweep gas)., (© 2021 The Authors.)

The effect of different deprotonators as well as washing steps and drying procedure on the synthesis of ZIF-8 from the mother liquor was investigated. The morphology, thermal stability, crystallinity, and surface area of the synthesized MOF were investigated. In addition, life-cycle assessment (LCA) or, in other words, eco-balance, was implemented as well. LCA compares the full range of environmental effects associated with the product by evaluating all inputs and outputs of material flows and predicting how such flow will affect the environment. ZIF-8 nanocrystals were synthesized from the recycled mother liquors using NaOH or NH 4 OH thus preserving the main characteristics of the ZIF-8 nanoparticles derived from the initial synthesis. The rest of the characterization methods confirmed the suitability of the synthesis methodology considering the phase purity of the obtained ZIF-8 and nanometer size particles. This procedure enabled us not only to obtain phase pure ZIF-8 but also to substantially decrease the amount of solvent used for washing making it a sustainable process., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)