Recycling

This study examines the psychosocial factors predicting municipal solid waste separation in Italy, applying and extending a model originally developed for Southern regions. The model integrates the Theory of Reasoned Action and the Value-Belief-Norm framework to explain how values, norms, and attitudes shape waste separation intentions and behaviours. Using data from 321 online survey respondents, this study tests the model’s validity in Northern Italy. Additionally, the study examines the relationships among the variables under investigation in people residing in the Northern and Southern regions of Italy. Findings confirm the model (χ² (10) = 28.118, p = 0.002, CFI = 0.956; RMSEA = 0.075; AIC = 8.118): bio-altruistic values and social norms significantly predict positive attitudes, which in turn determine behavioural intentions. Perceived distributive unfairness is negatively associated with attitudes toward waste separation. Separation behaviour is mainly influenced by internal attributions and knowledge, while egoistic values show a negative relationship. The multi-group analysis indicates a good model fit for both Northern and Southern samples (χ² (31) = 45.059, p = 0.049, CFI = 0.969; RMSEA = 0.053; AIC = −16.941), suggesting consistent psychosocial mechanisms. By integrating psychosocial insights with behavioural data, this research highlights the importance of knowledge, fairness, and social norms in promoting sustainable waste management. The findings provide practical guidance for policymakers and practitioners to design regionally communication and participation strategies that enhance the long-term sustainability of waste separation systems in Italy.

The growing demand for lithium, driven by its key role in rechargeable batteries and its use in electric vehicles, highlights the need for sustainable and environmentally friendly recovery strategies. Conventional methods, such as pyrometallurgy and hydrometallurgy, are effective but costly and harmful as they emit toxic compounds. Biohydrometallurgy has emerged as a promising alternative, as it uses microorganisms and their metabolites to solubilize metals under milder conditions. Biohydrometallurgy has emerged as a promising alternative, as it relies on microorganisms and their metabolites to solubilize metals under mild operating conditions. Nevertheless, challenges related to process efficiency and selectivity remain, particularly for lithium recovery. In this context, recent advances in metal-binding peptides have attracted increasing attention due to their inherent selectivity and the possibility of rational design and heterologous expression in well-established microbial hosts such as Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae. This review critically analyzes current biotechnological strategies and explores the integration of microbial bioleaching with peptide-based approaches as a complementary and environmentally friendly framework for the selective recovery of lithium and other metals from spent batteries and waste electrical and electronic equipment. Overall, this review provides an integrative conceptual framework that highlights the potential of combining microbial processes with metal-binding peptides to guide the development of more selective and sustainable biotechnological strategies for lithium recovery from secondary sources.

Mechanical milling is a relevant preliminary processing operation that is widely used for the reuse of various types of agro-industrial waste. The objective of this study was to conduct milling experiments of hazelnut (Corylus avellana L.) shell waste at different times (0.5, 1 and 1.5 min) and subsequently evaluate the particle size distribution (PSD) of the powders obtained by sieving methodology. In addition, flowability parameters were determined for the particles retained on the sieves, and their morphology and microstructure were examined using several microscopy techniques. The results demonstrated that the hazelnut shells were successfully fractionated under the milling conditions investigated (short milling times ≤ 1.5 min), and the histograms of the PSD exhibited a wide dispersion of sizes (≤1.7 mm). The particles retained from sieve₁₀₀ to residue exhibited poor or no flow, attributable to the high degree of cohesion between them. Morphological analysis based on optical microscopy and image analysis revealed that there was an increase in the aspect ratio parameter when the particle size decreased, meaning that the particles had elongated shapes. Microscopic analysis (SEM, AFM and CLSM) showed that the particles exhibited complex shapes and a comparable microstructure, comprising tightly packed clusters of sclerenchyma cells. From the microscopy images obtained (SEM and AFM), it was inferred that the cracks generated during blade impacts propagate along the middle lamella of the cells, allowing the cluster-like arrangement to be preserved. The CLSM results demonstrated that as the size of hazelnut shell particles decreases, the exposure of lignin on its surface is favored. The findings of this study demonstrate that hazelnut shell waste can be readily pre-processed using a blade grinder, thereby facilitating its reuse in applications that demand fine particle sizes (e.g., bioadsorption of pollutants and the production of biocomposite materials). Likewise, the results concerning the flowability parameters, microstructural arrangement, and morphological features of the different particle fractions obtained are crucial variables that must be considered. These variables significantly influence the possible applications for the revalorization of this type of agro-industrial waste.