While TiO₂ nanoparticles have shown potential as photocatalysts in the degradation of organic contaminants, their inability to absorb efficiently visible light has limited their industrial application. One strategy for solving this problem is monodoping TiO₂ photocatalysts with transition metals, which has worked in the degradation of several pollutants. However, it is not clear if this improvement is enough to offset the potential environmental impacts of adding metal ions to the synthesis of TiO₂. Herein, we have used Life Cycle Assessment (LCA) to determine the sustainability of monodoping TiO₂ with transition metals (Fe, Co, Mn and Ni, with a 1% weight ratio) to enhance the photocatalytic properties of the photocatalyst toward the degradation of Carbamazepine and Methyl Orange, under UV-A and visible light irradiation. We found that the addition of transition-metals has no significant effect on the environmental impacts associated with the synthesis of TiO₂, when a weight-based functional unit was considered. However, when photocatalytic activity was considered, major differences were found. Thus, our results demonstrate that the sustainability of monodoping with different transition metals is solely determined by their ability to enhance (or not) the photocatalytic activity of TiO₂. Our data also demonstrated that isopropyl alcohol constitutes a critical point in the synthesis of TiO₂ photocatalysts, with ethanol being a potential substitute.

Carbon dots (CDs) are carbon-based nanomaterials with remarkable properties that can be produced from a wide variety of synthesis routes. Given that “standard” bottom-up procedures are typically associated with low synthesis yields, different authors have been trying to devise alternative high-yield fabrication strategies. However, there is a doubt if sustainability-wise, the latter should be really preferred to the former. Herein, we employed a Life Cycle Assessment (LCA) approach to compare and understand the environmental impacts of high-yield and “standard” bottom-up strategies, by applying different life cycle impact assessment (LCIA) methods. These routes were: (1) production of hydrochar, via the hydrothermal treatment of carbon precursors, and its alkaline peroxide treatment into high-yield CDs; (2) microwave treatment of carbon precursors doped with ethylenediamine; (3) and (6) thermal treatment of carbon precursor and urea; (4) hydrothermal treatment of carbon precursor and urea; (5) microwave treatment of carbon precursor and urea. For this LCA, four LCIA methods were used: ReCiPe, Greenhouse Gas Protocol, AWARE, and USEtox. Results identified CD-5 as the most sustainable synthesis in ReCiPe, Greenhouse Gas Protocol, and USEtox. On the other hand, in AWARE, the most sustainable synthesis was CD-1. It was possible to conclude that, in general, high-yield synthesis (CD-1) was not more sustainable than “standard” bottom-up synthesis, such as CD-5 and CD-6 (also with relatively high-yield). More importantly, high-yield synthesis (CD-1) did not generate much lower environmental impacts than “standard” approaches with low yields, which indicates that higher yields come with relevant environmental costs.

Backgroung: The rising complexity and associated side effects of cancer treatments highlight the need for safer and more effective therapeutic agents. Carbon-based nanomaterials such as CDs have been gaining prominence for their unique characteristics, opening avenues for diverse applications such as fluorescence imaging, drug and gene transport, controlled drug delivery, medical diagnosis, and biosensing. Despite promising advancements in research, it remains imperative to scrutinize the properties and potential cytotoxicity of newly developed CDs, ensuring their viability for these applications. Methods: We synthesized four N-doped CDs through a hydrothermal method. Cell viability assays were conducted on A549 and UM-UC-5 cancer cells at a range of concentrations and incubation times, both individually and with the chemotherapeutic agent 5-fluorouracil (5-FU). Results: The obtained results suggest that the newly developed CDs exhibit suitability for applications such as bioimaging, as no significant impact on cell viability was observed for CDs alone.

A sustainable matrix based on eucalyptol essential oil/sawdust was developed and applied on laminated plywood. This finish aims to serve as a eucalyptol odor slow release. Eucalyptol odor release was monitored with gas chromatography coupled with a flame ionization detector (GC-FID: Limits of Detection and Quantification of 0.70 g/m³ and 2.11 g/m³, respectively, and with linearity up to 18.6 g/m³). Measurement of the eucalyptol odor released was performed during a six-month period, and it was found that the release followed a first-order exponential decay with a decay rate constant of 0.0169 per day. The half-life was determined to be of 48 days. The granulometry and particle size porosity of sawdust were analyzed by Scanning Electron Microscopy. A sawdust size fraction of 112–200 μm showed the best eucalyptol absorption capacity, with 1:3 masses ratio (sawdust:eucalyptol). The release duration of eucalyptol is influenced by the quantity of the eucalyptol–sawdust composite and the aperture size for release. Through the determination of this relationship, it was found that applying 15.0 g of the composite through a 0.8 mm diameter aperture resulted in a 6-month eucalyptol release period. This outcome is regarded as highly favorable, considering the inherent high volatility of eucalyptol and the relatively small amount of composite required for future product applications. The new product is characterized by a carbon footprint (considering the industry frontiers) of 5.94 kg CO₂eq/m² of plywood floor.