Synthetic zeolite materials from recycled glass and aluminium food packaging as potential oenological adjuvant

Turn-on fluorescent sensor based on curcumin@MOF-5 for the sensitive detection of Al3

Two fluorescent chemosensors based on MOF-5 and curcumin (A-curcumin@MOF-5 and B-curcumin@MOF-5) were designed and synthesized. The two curcumin@MOF-5 materials retained the framework structure of MOF-5 and the fluorescence properties of curcumin. Importantly, both curcumin@MOF-5 materials in ethanol displayed highly selective fluorescence enhancement responses toward Al³⁺ with the special pore structure of MOF-5 as the main reason for the high selectivity. The fluorescence intensities of the two curcumin@MOF-5 materials showed a good linear relationship with Al³⁺ concentration with low detection limits of 3.10 μM for A-curcumin@MOF-5 and 2.84 μM for B-curcumin@MOF-5, respectively. The complexation of curcumin with Al³⁺ inhibited the photoinduced electron-transfer (PET) process and further enhanced the fluorescence of the curcumin molecules. Both the curcumin@MOF-5 materials can be used as fluorescent sensors to identify and detect Al³⁺ in water samples.

Driving Forces of Cationic Dye Adsorption, Confinement, and Long-Range Correlation in Zeolitic Materials

Zeolitic materials are commonly used to capture emergent contaminants in water or complex aqueous effluents. The efficiency of this adsorption depends strongly on the guest-host interactions and on the surrounding environment with possible coadsorption of the solvent. Only a few experimental techniques are available to probe in situ the sequestration processes at the solid/liquid interface. We propose in the present work to combine the second harmonic scattering technique with isothermal titration calorimetry in order to investigate the adsorption and the confinement of a hemicyanine dye adsorbed inside faujasite materials. The methodology described here permits the quantification of the correlations between the confined dyes in the material and thus gives local information about the organization at the nanometer scale. Various impacts, such as the effect of the solvent type and the silicon to aluminum ratio of the zeolitic adsorbent, are quantitatively estimated and discussed. This work highlights that the most correlated system matches the higher adsorption capacity associated with the lower entropic contribution.

Application of natural and synthetic zeolites in the oenological field

Zeolites are crystalline hydrated aluminosilicates, of natural or synthetic origin, characterized by a microporous structure and high adsorption properties. They are employed as soil amendments and fertilizer carriers in agriculture, as catalysts, detergents, adsorbents and molecular sieves in many chemical processes, as well as in water and soil decontamination, and in food processing. They have been also tested in the oenological field for several potential applications; yet an overview on such topic is not still available. The present review summarizes the recent and innovative applications of zeolites in winemaking and supplies a critical discussion about their potential to prevent protein haze, tartrate instability or the appearance of certain defects, like light-struck off-flavour and earthy off-flavours. Further applications of these minerals in the management of winery wastes and in the analytical field are also reviewed. The outcomes of this work evidenced the need of further research on the use of zeolites in oenology for better exploiting their peculiar sorption and exchange properties, selecting the most efficient natural types and improving the performances of the synthetic ones, without disregarding the potential secondary effects of these treatments on wine quality.