Two strategies for encapsulating caffeine in ZIF-8 were carried out in this work: (1) one-step, in situ encapsulation where caffeine is added to a ZIF-8 synthesis solution and the MOF structure is formed around the entrapped molecule; and (2) ex situ encapsulation whereby caffeine is put into contact with previously synthesized or purchased ZIF-8. The products obtained were analyzed with XRD, TGA, Vis-UV, GC-MS, FTIR, (13)C NMR, and N 1s XPS to compare both encapsulation methods. Chemical and structural evidence indicated that the preferential adsorption site of caffeine molecules inside the ZIF-8 structure is near the methyl and CH groups of 2-methylimidazole ligand. These two groups interact with caffeine by van der Waals forces with methyl groups and via CH···O hydrogen bonds with C═O groups, respectively. In addition, the one-step encapsulation of caffeine in ZIF-8 produced high guest loading (ca. 28 wt % in only 2 h at 25 °C) and controlled release (during 27 days).

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.

A new material, UZAR‐S1, has been obtained by exfoliation of the layered precursor microporous titanosilicate JDF‐L1. The exfoliation consists of a first stage of proton exchange with histidine followed by intercalation with nonylamine and final extraction in HCl/water/ethanol solution. UZAR‐S1 is an exfoliated material composed of sheets of a few nanometers of thickness with a high aspect ratio, a BET specific surface area of 160 m2/g (JDF‐L1 scarcely adsorbs N2), and a Si/Ti atomic ratio below 6. The dispersion of this material in commercial polysulfone results in an improved H2‐selective mixed matrix membrane.