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 40-70 ºC) 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 ºC, 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.

The production of MOFs at large scale in a sustainable way is key if these materials are to be exploited for their promised widespread application. Much of the published literature has focused on demonstrations of preparation routes using difficult or expensive methodologies to scale. One such MOF is nano-zeolitic imidazolate framework-8 (ZIF-8) – a material of interest for a range of possible applications. Work presented here shows how the synthesis of ZIF-8 can be tracked by a range of methods including X-ray diffraction, thermo gravimetric analysis and inelastic neutron scattering – which offer the prospect of in-line monitoring of the synthesis reaction. Herein we disclose how the production of nano-ZIF-8 can be conducted at scale using the intermediate phase ZIF-L. By understanding the economics and demonstrating the production of 1 kg of nano-ZIF-8 at pilot scale we have shown how this once difficult to make material can be produced to specification in a scalable and cost-efficient fashion.

The present work is focused on the study of the effect that the casting solution concentration has on the morphology and gas separation performance of poly(ether- block -amide) copolymer membranes (Pebax ® MH 1657). With this aim, three different concentrations of Pebax ® MH 1657 in the casting solution (1, 3 and 5 wt%) were used to prepare dense membranes with a thickness of 40 µm. The morphology and thermal stability of all membranes were characterized by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, rotational viscometry and thermogravimetric analyses. An increase in crystallinity was notable when the amount of solvent in the Pebax ® MH 1657 solution was higher, mainly related to the polymer chains arrangement and the solvent evaporation time. Such characteristic seemed to play a key role in the thermal degradation of the membranes, confirming that the most crystalline materials tend to be thermally more stable than those with lower crystallinity. To study the influence of their morphology and operating temperature on the CO 2 separation, gas separation tests were conducted with the gas mixture CO 2 /N 2 . Results indicated that a compromise must be found between the amount of solvent used to prepare the membranes and the crystallinity, in order to reach the best gas separation performance. In this study, the best performance was achieved with the membrane prepared from a 3 wt% casting solution, reaching at 35°C and under a feed pressure of 3 bar, a CO 2 permeability of 110 Barrer and a CO 2 /N 2 selectivity of 36.

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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.

Poly(ether-block-amide) (PEBA, commercialized as Pebax) copolymer membranes show a highly promising platform for preparing high-performance membranes for CO 2 capture from process streams containing CH 4 and N 2 . Pebax combines high CO 2 affinity with the desired mechanical strength for polymeric membranes thanks to its flexible polyether segment and hard polyamide block, respectively. Furthermore, researchers have been improving the performance of these membranes by preparing a thin Pebax selective layer on top of porous supports and by incorporating inorganic and organic nanofillers into the Pebax matrix to overcome the permeance-selectivity limit. The chemical and structural characteristics of Pebax membranes according to the different fabrication techniques and parameters are discussed first. Then, the recent developments in terms of both Pebax-based thin film composite and mixed matrix membranes are summarized. Finally, thermal and water stabilities of these membranes are addressed.

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