Silvia Barbi

The growing interest in mitigating the effects associated with the extensive production and consumption of fossil-based plastics has led to increasing efforts in the development of biobased and biodegradable materials. In this setting, poly­(butylene adipate-co-terephthalate) (PBAT) has emerged as a viable biodegradable alternative to traditional polyesters. In this study, the manufacture of a PBAT-inulin composite film is investigated to assess its structural, mechanical, and environmental properties. A design of experiments (DoE) approach was applied to limit the number of experiments and find potential multivariate correlations (p-value <0.005) between composite formulation, e.g., inulin content, and mechanical properties. Results show that the inulin percentage has the highest influence on the strain at break, which is found to decrease as the percentage of inulin increases; as such, an ideal amount of inulin is found to be equal to 4.4−4.5% of the composite. From an environmental standpoint, results of a cradle-to-gate life cycle assessment (LCA) (1 kg of composite as the functional unit) show that PBAT production is the highest overall contributor to the impacts of the composite (68% average across categories), whereas inulin presents the highest contribution in the marine eutrophication (71%) and land-occupation (44%) categories. Among the processing steps, composite extrusion reports the highest average impacts at 14%. Also, a sensitivity analysis suggests that adopting biobased PBAT and increasing the percentage of renewable electricity consumed could reduce the cumulative environmental burdens. Overall, this integrated approach can provide valuable information for further optimization of both mechanical performance and environmental sustainability, in line with the principles of Green Chemistry and Green Engineering.

The reaction between aluminium and water has garnered significant interest in materials science due to its promising applications, particularly in hydrogen production. In this context, repurposing aluminium powder derived from waste presents a potentially sustainable pathway for low-impact hydrogen generation. This study explores the reaction mechanisms of various waste-sourced aluminium powders under different heating procedures in an uncontrolled (air) atmosphere. Post-reaction, the samples were analyzed using scanning electron microscopy (SEM) to assess their morphology, alongside energy-dispersive spectroscopy (EDS) for semi-quantitative chemical composition. Additionally, Rietveld refinement was applied to X-ray diffraction (XRD) data to identify the resulting crystalline compounds. The analysis revealed the formation of several aluminium-based compounds (such as AlN, Al ₂ O ₃ , Al ₂ MgO ₄ ), with no trace of pure aluminium remaining after thermal treatment. This finding highlights the high reactivity of the tested waste powders. Overall, the study offers valuable insights into the reaction pathways of aluminium powders and supports the potential of using waste aluminium in hydrogen production processes.

Environmentally sustainable methods for producing flexible electronics, such as paper-based energy harvesters in nanogenerators, are a major objective in materials science. In this frame, the present study investigated two different Komagataeibacter sp. strains (K2G30 and K2G44), never tested as biocatalysts for the production of bacterial cellulose (BC) functionalized with iron particles to provide potential electrical conductivity. Two functionalization strategies (ex situ and in situ) were evaluated using two iron compounds FeCl₂ and FeSO₄, individually and in combination (up to 0.1% w/v), to assess efficiency and feasibility. In addition, a Design of Experiment approach was implemented to calculate quantitative mathematical models to correlate the functionalization methods with the iron amount in the BC. Among the tested conditions, BC produced by strain K2G44 using the ex situ method with FeCl₂ showed the most promising results, achieving the highest iron content (~37% atomic weight) with a highly homogeneous dispersion of iron nanoparticles. Moreover, the in situ BC functionalization using FeSO₄ led to the formation of iron gluconate. FeSO₄ alone significantly enhanced BC production in the in situ process, with yields of 2.62 ± 0.15 g/L for K2G30 and 2.05 ± 0.09 g/L for K2G44.

The development of electrolyser technology is currently undergoing a breakthrough phase, poised to meet the upcoming demands for widespread hydrogen production under stringent requirements including high efficiency, purity, affordability, and rapid response to harness the full potential of renewable energy sources. In recent years, this rapid advancement necessitated concerted efforts supported by various diagnostic tools to achieve a comprehensive understanding of the underlying mechanisms governing electrolytic processes across diverse operating conditions. These tools prove particularly effective when capable of providing real-time insights into the features and behaviour of the studied system during operation. This paper presents a review of the latest diagnostic tools employed in the investigation of modern electrolyzers, with particular emphasis on electrochemical impedance analysis (EIS). It delves into how this tool facilitates a deeper comprehension of the fundamental electrochemical principles governing electrolysis, its evolution in the study of electrolysis, and its interconnectedness with other diagnostic methodologies.

With the aim of better identifying possible solutions to the actual critical issues regarding the uncertain performance of anion exchange membrane (AEM) electrolyzers, analytical mathematical models related to their materials’ selection are developed through multivariate analysis. An objective evaluation and selection of such solutions are herein proposed through a statistical approach, based on multivariate data analysis (ANOVA), involving data from literature based on academic and commercial datasets. First, a classification of the materials of interest is made; thereafter, three electrolyzer properties are evaluated as responses (cost, current density, and time stability). In the results, it is demonstrated that each property considered is promoted by a different material's combination. For example, the highest current density (>1123 mA cm⁻²) is achieved by employing KOH as electrolyte, whereas the lowest assembly cost (≈2 $ Kg⁻¹) is related to platinum‐based cathodes coupled with membranes at a higher loading thickness (130 μm). The selection of materials in this way will aim to gather the most suitable ones based on objective criteria, which will further drive the development of electrolyzers that are increasingly efficient and sustainable.

In recent years, the EU policy identified the hydrogen as one of the main energy vectors to support the power production from renewable sources. Coherently, electrolysis is suitable to convert energy in hydrogen with no carbon emission and high purity level. Among the electrolysis technologies, the anion exchange membrane (AEM) seems to be promising for the performance and the development potential at relatively high cost. In the present work, AEM electrolysers, and their technological bottlenecks, have been investigated, in comparison with other electrolysers’ technology such as alkaline water electrolysis and proton exchange membranes. Major efforts and improvements are investigated about innovative materials design and the corresponding novel approach as main focus of the present review. In particular, this work evaluated new materials design studies, to enhance membrane resistance due to working cycles at temperatures close to 80 °C in alkaline environment, avoiding the employment of toxic and expensive compounds, such as fluorinated polymers. Different strategies have been explored, as tailored membranes could be designed as, for example, the inclusion of inorganic nanoparticles or the employment of not-fluorinated copolymers could improve membranes resistance and limit their environmental impact and cost. The comparison among materials’ membrane is actually limited by differences in the environmental conditions in which tests have been conducted, thereafter, this work aims to derive reliable information useful to improve the AEM cell efficiency among long-term working periods.

Paper is one of the most promising materials for food packaging and wrapping due to its low environmental impact, but surface treatments are often needed to improve its performance, e.g., the resistance to fats and oils. In this context, this research is focused on the formulation of a new paper bio-coating. Paper was coated with liquids containing poly(hexano-6-lactone) (PCL), glycerol and variable percentages of starch (5–10% w/w PCL dry weight), agar-agar (0–1.5% w/w PCL dry weight), and polyethylene glycol (PEG) (5% or 15% w/w PCL dry weight) to improve coating uniformity and diffusion. A design of experiments approach was implemented to find statistically reliable results in terms of the best coating formulation. Coated paper was characterized through mechanical and physical properties. Results showed that agar content (1.5% w/w PCL dry weight) has a beneficial effect on increasing the resistance to oil. Furthermore, the best coating composition has been calculated, and it is 10% w/w PCL dry weight of starch, 1.5% w/w PCL dry weight of agar, and 15% w/w PCL dry weight of PEG.

Paper is one of the most promising materials for food packaging and wrapping due to its low environmental impact, but surface treatments are often needed to improve some performance, e.g. the resistance to fats and oils. In this context, this research is focused on the formulation of a new paper bio-coating. Paper was coated with liquids containing Poly(hexano-6-lactone) (PCL), Glycerol and variable percentages of starch (5 - 10% w/w PCL dry weight), agar agar (0 - 1.5% w/w PCL dry weight) and PEG (5% or 15% w/w PCL dry weight) to improve coating uniformity and diffusion. A Design of Experiments approach was implemented to find statistically reliable results in terms of best coating formulation. Coated paper was characterized through mechanical and physical properties. Results showed that agar content (1.5% w/w PCL dry weight) has a beneficial effect on increasing the resistance to oil. Furthermore, the best coating composition has been calculated, and it is: 10% w/w PCL dry weight of Starch, 1.5% w/w PCL dry weight of agar and 15% w/w PCL dry weight of PEG.

The modern agriculture system based on open-field crops requires a lot of energy and resources in terms of soil, water, and chemicals. Vertical farming (VF) systems could be a viable alternative for some types of cultivation that are receiving interest thanks to their high modularity, optimized water and nutrients use, and LEDs employment as an energy-efficient light source. However, VF design and installation are expensive and require well-tailored optimization depending on the specific crop to increase its competitiveness. This work analyzed the effects of different combinations of NPK (nitrogen-phosphorus-potassium) slow-release fertilizers and LED-based light recipes on the growth of baby leaf lettuce (Lactuca sativa L.), taking advantage of the Design of Experiments (DoE) methodology. The type of slow-release fertilizer, its quantity measured as the number of aggregates from 0 to 6, and the type of light recipe were considered as input factors, and their possible influence on the growth of lettuce (in terms of morphological parameters) in a controlled indoor farming system was measured. Results suggest that using higher fertilizer inputs equal to six aggregates leads to an increase of average leaf area equal to 46% (from 13.00 cm² to 19.00 cm²), while the fresh weight of lettuce increases by 65% (from 1.79 g to 2.96 g). However, the height of plants also depends on the combination of the light recipes. In particular, the separate coupling of higher inputs of two fertilizers and light recipes leads to an increase in the height of lettuce equal to 33% (from 6.00 cm to 8.00 cm).