RSC sustainability最新文献

Seasonal snow covers up to 33% of the Earth's surface. Fresh falling snow serves as a snapshot of atmospheric processes and can take up pollutants. Once deposited, snow can affect the Earth's radiation and climate change, and its melting and accumulation processes can affect human health. Little has been done for snow pollution remediation, especially regarding emerging materials and nano/microplastics in urban regions. We present a sustainable, cost-effective snow remediation filtering system made of multilayer clay-based minerals, specifically kaolin and montmorillonite, capable of removing nano/micro-contaminants from snow. In addition, a recycled metallic mesh with various pore sizes, including nano/micro size, can remove substantial snow contaminants. Using a suite of technologies including high-resolution S/TEM, Pelletier ice nucleation counter, NALDI mass spectrometry, Photoacoustic Extinctiometer (PAX), triple quad ICP-MS/MS, and TOC counter, we found that the clay-mineral setup is highly efficient. For instance, it removes metallic species (>95%), plastic micro/nanoparticles like polyethylene glycol and polyethylene (>99%), black carbon (>93%), and total organic carbon (>50%) from dirty snow sampled in the primary snow depository in downtown Montreal. This sustainable and inexpensive method is promising for significantly reducing the environmental impact of snow pollutants, improving current snow remediation practices in urban areas, decreasing the re-emission of contaminants in air, soil, and water leaching, and improving the ecosystem and human health.

Photocatalysis is a low-cost solution to efficiently remove resilient emergent pollutants from wastewater with complex chemical structures, such as pharmaceuticals. Titanium dioxide (TiO₂) is the most studied photocatalyst and is usually functionalised with gold (Au) nanoparticles to prevent electron–hole pair recombination and extend visible radiation absorption. However, conventional synthesis techniques use toxic chemicals and present high energy consumption. The focus of this work is to present and optimize a green synthesis method using the flavonoid rutin – a natural compound found in various plants – as the reducing agent at room temperature to decrease the environmental impact and optimise the chemical, physical, and photocatalytic properties of Au/TiO₂ nanoparticles with concentrations of Au of 0.025, 0.1, and 1 wt%. Through ciprofloxacin (CIP) degradation under UV and simulated solar radiation, enhanced photocatalytic efficiency is observed due to adding Au nanoparticles, proving that rutin is a suitable reducing agent for green nanoparticle synthesis.

For the manufacture of enantiopure amines, greener synthesis processes are needed. Transaminases (TAs) are able to produce chiral amines with excellent enantioselectivity and in mild conditions, and can be immobilized to target stability, recoverability, and reusability. In the perspective of process intensification, we propose to study TA immobilization onto polymeric membranes. Two main immobilization strategies were investigated, requiring prior membrane surface functionalization. On the one hand, a polyacrylonitrile (PAN) membrane surface was partially hydrolyzed and coated with polyethyleneimine (PEI) to electrostatically trap TAs. On the second hand, a polypropylene (PP) membrane was coated with polydopamine (PDA), which was subsequently modified with glycerol diglycidyl ether (GDE) in order to covalently graft TAs. The successful membrane functionalization was confirmed by surface characterization techniques (infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, and scanning electron microscopy). Enzyme leaching was observed from the functionalized PAN membrane, highlighting the need to post-treat the reversibly immobilized TAs to improve their anchoring. The covalent coupling of TAs with PEI using glutaraldehyde (GA) was found highly effective to avoid leaching and to increase the enzyme loading, without affecting the specific activity of the biocatalyst. Similarly, the covalent grafting of TA onto functionalized PP membranes yielded very efficient biocatalysts (retaining 85% specific activity with respect to soluble TA) displaying perfect recyclability throughout successive cycles. Immobilizing either the S-selective HeWT or the R-selective TsRTA resulted in robust heterogeneous biocatalysts with antagonist enantioselectivities. Thus, chiral amine synthesis can be performed effectively with biocatalytic membranes, which paves the way to intensified continuous flow synthesis processes.

The functionality inherent in lignin-derivable aromatics (e.g., polar methoxy groups) can provide a potential opportunity to improve the hydrophilicity of polysulfones (PSfs) without the need for the additional processing steps and harsh reagents/conditions that are typically used in conventional PSf modifications. As determined herein, lignin-derivable PSfs without any post-polymerization modification exhibited higher hydrophilicity than comparable petroleum-based PSfs (commercial/laboratory-synthesized) and also demonstrated similar hydrophilicity to functionalized BPA-PSfs reported in the literature. Importantly, the lignin-derivable PSfs displayed improved thermal properties relative to functionalized BPA-PSfs in the literature, and the thermal properties of these bio-derivable PSfs were close to those of common non-functionalized PSfs. In particular, the glass transition temperature (T_g) and degradation temperature of 5% weight loss (T_d5%) of lignin-derivable PSfs (T_g ∼165–170 °C, T_d5% ∼400–425 °C) were significantly higher than those of typical functionalized BPA-PSfs in the literature (T_g ∼110–160 °C, T_d5% ∼240–260 °C) and close to those of unmodified, commercial/laboratory-synthesized BPA-/bisphenol F-PSfs (T_g ∼180–185 °C, T_d5% ∼420–510 °C).

2,5-Furan Dicarboxylic methyl Ester (FDME), a highly valued monomer for the synthesis of biobased polyesters, has been prepared through a new synthetic strategy that consists of the direct carboxylation of methyl furoate in two steps: the first one involves a solvent-free reaction using a moderate CO₂ pressure (10 bar), a base (Cs₂CO₃) and a cobalt-based heterogeneous catalyst (HCP-Salphen-Co) for 6 h, which was prepared using mechanochemical polymerization. The second step consists of an acid esterification using standard conditions. The CO₂-based FDME synthesized with this strategy was successfully reacted with a diol derived from vanillin, thus obtaining a CO₂ and a completely bio-based polyester which exhibited high thermal stability with a starting degradation temperature of 250 °C and a glass transition temperature of 104 °C.

Technological development is increasingly driven by environmental sustainability, with labels like ‘green’ gaining traction. However, the complex interactions in a product's life cycle make the environmental impact of materials and chemicals highly context-dependent, highlighting the need for context-specific environmental assessments. Anisole has been popularly used as a “green” alternative to chlorobenzene for perovskite solar cell (PSC) fabrication. This work validates the technical and environmental performance of anisole in the fabrication of PSCs. PSCs exhibiting conversion efficiencies exceeding 22% can be attained by using anisole as an antisolvent. Moreover, around 50% reduction in the potential toxicity is obtained when substituting chlorobenzene for anisole embodied in the carcinogenic human and ecosystem toxicity impact categories. Nonetheless, anisole embodies higher impact in all 14 remaining impact categories. This is due to anisole's multistep synthesis procedure that contributes to more than double the climate change impact of chlorobenzene, synthesized by a single-step method. To reduce the emissions several recommendations and strategies are proposed. Ultimately, it has been proved that context-specific and transparent environmental assessments are needed to make informed decisions in research and development leading to environmentally sustainable solutions.

The resistance of bacteria to antibiotics poses a significant challenge in the current global landscape. Despite this urgency, the pace of drug development has not matched the pressing need. Addressing this gap, we have developed zinc-doped carbon dots (Zn-Cdots) using biomass as a carbon source by a simple, and eco-friendly hydrothermal method to treat bacterial infection. Plant-derived biomass serves as an excellent source of various bioactive molecules, making it a viable carbon source for synthesizing Zn-Cdots. The characterization of Zn-Cdots was performed using multiple techniques, including UV-Visible spectroscopy, photoluminescence spectroscopy, TEM analysis, XRD, FTIR and XPS. The Zn-Cdots exhibit superior antibacterial properties in combating Gram-negative and Gram-positive bacterial strains, specifically Serratia marcescens and Staphylococcus aureus compared to the precursor biomass extract. Additionally, ROS measurements revealed the antioxidant property of Zn-Cdots, while agarose gel electrophoresis studies confirmed that the interaction between pDNA and Zn-Cdots heightened the antibacterial activity of Zn-Cdots. Moreover, the ABTS assay and the TMB assay both validated the antioxidant activity of Zn-Cdots, revealing high efficacy in scavenging free radicals and further highlighting its potential in mitigating oxidative stress alongside potent antibacterial efficacy.