Rosa Taurino

A B S T R A C T Chitosan is a biomaterial characterized by biodegradability, biocompatibility with human tissues, antimicrobial and antifungal activities, and for these reasons has been proposed in many different fields. The present work highlights the potentiality of chitosan as additive for active PVC-based composites, prepared by termo-mechanical process, with good mechanical-physical properties and antimicrobial activity. A specific mechanical characterization shows as elastic modulus and tensile strength increase with the chitosan concentration, as well as dynamical storage and loss moduli. These findings evidence that a significant interaction between chitosan and PVC occurs. The thermal stability and preliminary antimicrobial tests are encouraging.

Lightweight geopolymers from wastes with reduced thermal conductivity have become an important
trend for green buildings sector. In this work, organic-inorganic hybrid geopolymers were prepared from
polyurethane powders wastes (polyurethane foam and polyisocianurate foam). Chemical, physical and
mechanical properties of geopolymers, manufactured with different percentages of polyurethane wastes
are reported and discussed. The FTIR spectroscopy allowed to verify the influence of both polyurethane
powders on the framework structure revealing H-bonds between polyurethane and inorganic phase.
Flexural and compressive strengths showed that content and typology of the used polyurethane wastes
affected the material behavior. The strength of hybrid geopolymers was maximized with polyisocianurate
foam waste addition in a concentration lower than 14% in weight. Thermal conductivity was carried
out on appropriate samples, showing that the hybrid geopolymers exhibit satisfactory isolation properties.
The new materials proposed in this work represents an innovative solution, enhancing the thermal
resistance of the buildings by using a waste intended for landfill.

Starting from (but not limited to) their importance in the Italian context, three agricultural substrates, two of fruit origin (grape seeds and plum stones) and one of herbaceous origin (woad), were comparatively tested for both biomethane production and digestate characterization. The anaerobic digestion tests showed that grape seeds had the highest net methane production of 253.0 NmL g volatile solids (VS)(-1), followed by plum stones, whose best resulting net methane production was 174.7 NmL gVS(-1), and finally by woad with a net methane production of 153.1 NmL gVS(-1). Interestingly, the best methane productions of the fruit substrates were obtained with different substrate to inoculum ratios (on a VS basis), 1:1 for grape seeds but 2:1 for plum stones. On the other hand, a three-month ageing of woad caused a limited reduction of methane production. The estimation of obtained degrees of conversion, carried out on a chemical oxygen demand (COD) basis for the specific tests achieving the respective best methane productions, gave values of 48%, 31%, and 33% for grape seeds, plum stones, and woad, respectively. The estimated degrees of conversion were evaluated along with the respective methane productions and substrate COD/VS ratios. The comparison of Fourier transform infrared (FT-IR) spectra and differential thermal analysis (DTA) profiles, carried out for selected digestates in pairs, revealed some distinctive differences in the relative intensities or presence and absence of particular peaks in the FT-IR spectra and in the relative intensities of the exothermic peaks or horizontal curve shifting of the DTA profiles.

A combined experimental evaluation of methane production (obtained by anaerobic digestion) and detailed digestate characterization (with physical-chemical, thermo-gravimetric and mineralogical approaches) was conducted on two organic substrates, which are specific to Italy (at regional and national levels). One of the substrates was grape seeds, which have an agricultural origin, whereas the other substrate was vegetable-tanned leather dust, which has an industrial origin. Under the assumed experimental conditions of the performed lab-scale test series, the grape seed substrate exhibited a resulting net methane production of 175.0 NmL g volatile solids (VS)(-1); hence, it can be considered as a potential energy source via anaerobic digestion. Conversely, the net methane production obtained from the anaerobic digestion of the vegetable-tanned leather dust substrate was limited to 16.1 NmL gVS(-1). A detailed characterization of the obtained digestates showed that there were both nitrogen-containing compounds and complex organic compounds present in the digestate that was obtained from the mixture of leather dust and inoculum. As a general perspective of this experimental study, the application of diversified characterization analyzes could facilitate (1) a better understanding of the main properties of the obtained digestates to evaluate their potential valorization, and (2) a combination of the digestate characteristics with the corresponding methane productions to comprehensively evaluate the bioconversion process.

The aim of this study was the surface functionalization of a new green ceramic material, obtained using packaging glass waste (PGW), to improve its cleanability. This objective was reached through the deposition by air-brushing of a nanostructured coating based on titania–silica sol–gel suspension. The coatings were deposited on both glazed and unglazed ceramic substrates and the thermal treatment conditions (temperature) were optimized. The obtained results suggest that the applied coatings are transparent and show a good scratch resistance and photocatalitic activity under the tested conditions. The photodegradation process and the mechanical properties are clearly affected by the thermal treatment and thus by the sample surface roughness. The best surface properties were obtained with a thermal treatment at temperature of 150 1C. These coatings do not exhibit either cracks from the substrate. All in all, the developed surface modified ceramic material is attractive as potential sustainable building material.