Chitin nanoparticles are responsible for the outstanding mechanical properties found in the exoskeletons of crustaceans and are finding applications in many scientific and technological fields. Following a Circular Economy approach, diverse biomass wastes can be valorized to be reintroduced back into the economic cycle while preventing biowaste landfill upon isolation of chitin nanoparticles. Novel environmentally sustainable paths over the conventional chitin nanoparticle extraction involving harsh acid-hydrolysis treatments from crustacean shells have been recently proposed. In particular, fungi emerge as an attractive alternative provided the demineralization process with acids such as HCl is circumvented. In spite of this recognized virtue, no works have quantified the environmental impacts of these processes. The life-cycle assessment methodology is applied to close this gap and quantify the cradle-to-gate impacts of chitin nanofibril extraction from fungi. The results are compared to conventional chitin nanocrystal hydrolytic isolation processes from shrimp shells, chitin powder, and crab shells, together with sulfuric-acid-induced hydrolysis of microcrystalline cellulose to cellulose nanocrystals. Eighteen impact indicators are analyzed scaling-up laboratory quantities into processes treating 1 kg of biowastes. A global warming potential value of 18.5 kg•CO 2 -equiv per 1 kg of chitin nanofibrils is obtained, well below the 906.8, 105.2, 543.5, and 177.9 kg CO 2equiv•kg −1 values obtained for chitin nanocrystals from shrimp shells, chitin powder, crab shells, and cellulose nanocrystals, respectively. A sensitivity analysis shows a 10.1−62.6% impact decrease to a minimum value of 14.7 kg CO 2 -equiv•kg −1 for chitin nanofibril isolation from fungi considering 95% recirculation of the solvent/NaOH, highlighting the environmentally sustainable character of chitin nanofibril extraction from fungi. The potential application of chitin nanoparticles into environmentally sustainable materials and devices is explored. These results provide novel cues for the environmentally friendly synthesis of nanochitin, guiding the implementation of sustainable approaches in the field of biomass nanoparticles.

The global demand for lithium-ion batteries (LIBs) has witnessed an unprecedented increase during the last decade and is expected to do so in the future. Although the service life of batteries could be expanded using Circular Economy approaches such as repair or remanufacture, batteries will inevitably become a huge waste stream as electric vehicles gain popularity. Battery recycling reintroduces end-of-life materials back into the economic cycle and prevents landfill scenarios. The reclamation of materials from spent batteries in general, and cathodes in particular, reduces the pressure over finite critical raw materials such as cobalt, nickel, lithium, or manganese and avoids severe heavy metal contamination issues associated with battery disposal. To establish a sustainable battery-recycling industry, the environmental impact assessment of cathode-recycling approaches is urgently needed. Accordingly, a life-cycle assessment methodology is applied to quantify and compare the environmental impacts of nine hydrometallurgical laboratory-scale LIB cathode-recycling processes in 18 impact indicators such as global warming potential. The LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode is selected given its predominant market share among electric vehicles. Hydrometallurgical recycling approaches based on inorganic acid-leaching (hydrochloric, sulfuric, and phosphoric acids), inorganic alkali-leaching (ammonia/sodium sulfite), organic leachates (citric, formic, or lactic acids), and bioleaching processes are analyzed. Scaling up the recycling to 1 kg cathode, global warming values from 25.1 to 95.2 kg•CO 2 -equiv per 1 kg of recycled cathode are obtained. The processes based on HCl and H 2 SO 4 /H 2 O 2 and the autotrophic bio-leaching process are preferred to lower greenhouse gas emissions and toxicity-and resource-related potential impacts. The choice of chemicals, the energy consumption, and more importantly, material efficiency emerge as the cornerstones to achieve environmentally sustainable processes. A sensitivity analysis demonstrates the potential to reduce the impacts by transitioning to a renewable energy mix, reaching a global warming value of 5.01 kg•CO 2 -equiv•kg cathode −1 . These results provide guidance toward further process optimization through eco-design approaches, securing the long-term sustainability of LIBs.