Sustainability analysis in the mining sector: a case study on new recycling technologies for sulphidic mine residues valorisation

Research has demonstrated that mining activities can cause serious impacts on the environment, as well as the surrounding communities, mainly due to the unsafe storage of mine tailings. This research focuses on the sustainability assessment of new technologies for the recovery of metals from mine residues. The assessment consists in the evaluation of the environmental, economic, and social impacts through the Life Cycle based methods: Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and Social Life Cycle Assessment (SLCA). The analyses are performed on the Mondo Minerals bioleaching project, which aim is to recover nickel and cobalt from the Sotkamo and Vuonos mine tailings. The LCA demonstrates that the project contributes to the avoided production of nickel and cobalt concentrates from new resources, hence reducing several environmental impacts. The LCC analysis shows that the company’s main costs are linked to the bioleaching process, caused by electricity consumption and the chemicals used. The SLCA analyses the impacts on three main stakeholder categories: workers, local community, and society. The results demonstrated that a fair salary (or the absence of it) impacts the workers the most, while the local community stakeholder category impacts are related to the access to material resources. The health and safety category is the most impacted category for the society stakeholder. The environmental and economic analyses demonstrate that the recovery of mine tailings may represents a good opportunity for mine companies both to reduce the environmental impacts linked to mine tailings and to increase the profitability. In particular, the project helps reduce the amounts of metals extracted from new resources and demonstrates that the use of the bioleaching technology for the extraction of metals can be economically profitable.

Comment (ne pas) devenir Parisien - Le guide ultime du parfait autochtone de la capitale: proposta di traduzione

L’objet de ce mémoire de maîtrise est la traduction du français en italien du guide humoristique Comment (ne pas) devenir Parisien – Le guide ultime du parfait autochtone de la capitale, écrit par la journaliste Caroline Rochet et publié en 2012 par Leduc.s Éditions. Ce mémoire a pour but de relier les aspects pratiques de la traduction avec ses principes théoriques et représente une piste de réflexion sur la nature complexe et fascinante de la traduction considérée comme médiation culturelle. Ce mémoire se compose de cinq chapitres : après une introduction illustrant la structure et les buts du mémoire, le premier chapitre présente l’œuvre originale, sa maison d’édition et l’auteur du guide. Le deuxième chapitre est dédié à l’analyse du texte : au genre textuel et à la typologie textuelle de l’œuvre, à son style, au profil socio-professionnel de la langue de l’auteur et au bagage de connaissances du destinataire. Le troisième chapitre expose le parcours d’approfondissement théorique suivi pour arriver au choix de la stratégie traductive convenable, c’est-à-dire la valorisation de la composante exotique. Le quatrième chapitre est consacré à la traduction du texte. Le dernier chapitre est constitué par deux sections : un commentaire sur les principaux aspects problématiques rencontrés pendant la traduction et sur les tactiques adoptées pour les résoudre (information invariante, information modifiée, information ajoutée et contenu éliminé) ; un commentaire dédié à la phase de rédaction d’un texte qui respecte le genre, le style et le fil conducteur du guide, c’est-à-dire l’ironie, ainsi que la formule d’interlocution la plus adapte à ce texte en langue italienne. Ces cinq chapitres sont suivis par une conclusion qui résume les différentes phases rencontrées pendant la traduction et est accompagnée par une réflexion sur la médiation interlinguistique considérée comme art d’écrire, liberté mais prise de responsabilité aussi.

Extraction of antioxidants from corn by-products for applications in bio-based polymer matrices

The objective of this dissertation is the evaluation of the exploitability of corn cobs as natural additives for bio-based polymer matrices, in order to hone their properties while keeping the fundamental quality of being fully bio-derived. The first part of the project has the purpose of finding the best solvent and conditions to extract antioxidants and anti-degrading molecules from corn cobs, exploiting room and high-temperature processes, traditional and advanced extraction methods, as well as polar and nonpolar solvents. The extracts in their entirety are then analysed to evaluate their antioxidant content, in order to select the conditions able to maximise their anti-degrading properties. The second part of the project, instead, focuses on assessing chemical and physical properties of the best-behaving extract when inserted in a polymeric matrix. To achieve this, low-density polyethylene (LDPE) and poly (butylene succinate – co – adipate) (PBSA) are employed. These samples are obtained through extrusion and are subsequently characterised exploiting the DSC equipment and a sinusoidally oscillating rheometer. In addition, extruded polymeric matrices are subjected to thermal and photo ageing, in order to identify their behaviour after different forms of degradation and to assess their performances with respect to synthetically produced anti-degrading additives.

Synthesis and characterisation of electrospun gold on ceria catalysts

Cerium oxide in catalysis can be used both as support and as a catalyst itself. Ceria catalyses many oxidations reactions, its excellent catalytic properties are due to its store oxygen storage capacity (OSC) and the reticular defects present on its surface. Different morphologies expose different reticular planes, and different reticular planes can expose different amounts of defects. The preparation method of cerium oxide can influence the surface area, morphology, and the number of defects in the sample. This work is focused on different preparation methods for gold nanoparticles supported on 1D nanostructures of cerium oxide prepared via electrospinning, their XRD, DRUV-Vis and Raman characterizations, and their catalytic performance on the oxidation reaction of HMF to FDCA.

Polyhydroxyalkanoates production from salted food waste using mixed microbial cultures.

Plastic is an essential asset for the modern lifestyle, given its superiority as a material from the points of view of cost, processability and functional properties. However, plastic-related environmental pollution has become nowadays a very significant problem that can no longer be overlooked. For this reason, in recent decades, the research for new materials that could replace fossil fuel-based plastics has been focused on biopolymers with similar physicochemical properties to fossil fuel-based plastics, such as Polyhydroxyalkanoates (PHA). PHAs are a family of biodegradable polyesters synthesized by many microorganisms as carbon and energy reserves. PHA appears as a good candidate to substitute conventional petroleum-based plastics since it has similar properties, but with the advantage of being biobased and biodegradable, and has a wide range of applications (e.g., packaging). However, the PHA production cost is almost four times higher (€5/kg) than conventional plastic manufacturing. The PHA production by mixed microbial cultures (MMC) allows to reduce production costs as it does not require aseptic conditions and it enables the use of inexpensive by-products or waste streams as these cultures are more amenable to deal with complex feedstocks. Saline wastewaters (WWs), generated by several industries such as seafood, leather and dairy, are often rich in organic compounds and, due to a strong salt inhibition, the biological treatments are inefficient, and their disposal is expensive. These saline WWs are a potential feedstock for PHA production, as they are an inexpensive raw material. Moreover, saline WWs could allow the utilization of seawater in the process as dilution and cleaning agent, further decreasing the operational costs and the environmental burden of the process. The main goal of the current project is to assess and optimize the PHA production from a mixture of food waste and brine wastewater from the fishery industry by MMC.