RSC sustainability最新文献

An integrated CO₂ capture and conversion system utilizing metal hydroxide salts has been developed to capture CO₂ from various sources including air in the form of carbonate salts and convert them directly into a synthetic fuel; methane. Nickel catalysts have previously been shown to convert carbonate salts, such as K₂CO₃ and Na₂CO₃, to methane. However, the productivity of these systems was rather modest in comparison to other catalysts based on ruthenium metal. With the help of lanthanide promoters, the methane productivity of nickel catalysts has been greatly improved. For the most part, the catalytic performance of the lanthanide promoted nickel catalysts followed the lanthanide contraction trend, i.e. the smaller the atomic size of the lanthanide, the higher the methane yield. Furthermore, the lanthanide promoted nickel catalysts are also stable under the alkaline conditions employed, maintaining their activity over five cycles of integrated CO₂ capture and conversion. Lastly, the lanthanide promoted nickel catalysts were demonstrated to be more economical compared to ruthenium- and unpromoted nicked-based catalysts.

Cement production is responsible for approximately 7% of anthropogenic CO₂-equivalent (CO_2e) emissions, while characterised by low margins and the highest carbon intensity of any industry per unit of revenue. Hence, economically viable decarbonisation strategies must be found. The costs of many emission reduction strategies depend on geographical factors, such as plant location and proximity to feedstock or on synergies with other cement producers. The current literature lacks quantification of least-cost decarbonisation strategies of a country or region's total cement sector, while taking stock of these geospatial differences. Here, we quantify which intervention ensembles could lead to least-cost, full decarbonisation of the European cement industry, for multiple European regions. We show that least-cost strategies include the use of calcined clay cements coupled with carbon capture and storage (CCS) from existing cement plants and direct air capture with carbon storage (DACCS) in locations close to CO₂ storage sites. We find that these strategies could cost €72–€75 per tonne of cement (t_cement⁻¹, up from €46–€51.5 t_cement⁻¹), which could be offset by future costs of cement production otherwise amounting to €105–€130 t_cement⁻¹ taking the cost of CO_2e emission certificates into account. The analysis shows that for economically viable decarbonisation, collaborative and region-catered approaches become imperative, while supplementary cementitious materials including calcined clays have a key role.

Modern engines are designed for very close contact between shearing planes, which requires high-performance boundary lubrication, delivered by lubricant base oils formulated with an array of additives. Commercial additive packages typically contain metals, sulfur, and phosphorus, which act as poisons to catalytic converters (thereby increasing emissions), increase wear and contribute to corrosion (which lowers the lifespan of engines). Ionic liquids (ILs), which are low-melting organic salts, have been extensively studied as lubricant additives; although some commercially available ionic liquids perform well as friction modifiers, they suffer from low solubility in the oil matrix and may cause corrosion due to residual chloride content. Here, we report nine new, task-specific ionic liquids, designed to act as ashless lubricant additives, comprising boron-containing cations for enhanced wear reduction, carboxylic acid anions to reduce friction, and modified alkyl chains to enhance solubility in the base oil. All ILs were inherently free from metals, sulfur, and phosphorus, and synthesised through a halide-free route. Their speciation was studied through multinuclear NMR and Raman spectroscopies, followed by studies of solubility in Group III+ base oil. Their performance as lubricant additives was assessed in terms of friction reduction and wear scar reduction, benchmarked against glycerol mono-oleate (GMO), a commercially availabe lubricant additive.

The massive growth in the human population, along with an improved healthcare system, resulted in the discharge of a large variety of active pharmaceuticals, including antibiotics, into the water stream leading to genotoxic, mutagenic, and ecotoxicological effects on plants, animals, and human. In this study, cost-effective and environmentally sustainable activated carbon adsorbents with composite pore structures have been prepared from agricultural waste materials, peanut shells and areca nut fibers, through a facile method. Phosphoric acid (H₃PO₄) of two different concentrations (20% and 40%) was used for preparing the activated carbons. All the activated carbon samples showed reasonably high specific surface area (SSA) ranging between 580–780 m² g⁻¹. The SSA of the activated carbon obtained from peanut shells was higher than those obtained from the areca nut fibers. The adsorption characteristics of the prepared activated carbons were assessed for the common active pharmaceuticals, paracetamol, amoxicillin, and aspirin, in an aqueous medium. The rate of adsorption of the activated carbon was very high, and about 90% of the paracetamol was adsorbed within 5 min of contact. The adsorption kinetics followed a pseudo-second-order kinetic model. The paracetamol adsorption capacity of the activated carbons obtained from the Langmuir adsorption isotherm (monolayer) model was 67 mg g⁻¹. Regeneration and reuse of the adsorbent for the removal of paracetamol were also studied for up to 5 cycles. The present research work ensures the “3 Rs” principle [reduce (waste), reuse and recycle] of environmental sustainability.

This work presents a novel method for generating bimetallic silver and zinc oxide nanoparticles (Ag/ZnO-NPs) using Hylocereus costaricensis (HC) stem extract and microwave irradiation. Silver and zinc oxide nanoparticles were prepared separately during the synthesis process, and they were directly mixed to produce bimetallic Ag/ZnO-NPs. A thorough characterisation was conducted utilising various analytical methods to clarify the formed nanoparticles' structural, morphological and constitutional characteristics. The conventional agar well diffusion technique was then used to assess the Ag/ZnO bimetallic nanoparticles' antibacterial activity towards Staphylococcus aureus and Escherichia coli, the two most common human pathogenic bacteria. The characterisation analysis showed the successful synthesis of bimetallic Ag/ZnO-NPs with a cluster-like spherical alloy-type morphology with an average hydrodynamic diameter of 281.7 nm and a direct band gap of 2.90 eV. The antibacterial results revealed that bimetallic Ag/ZnO-NPs have a solid combinatorial antibacterial activity, underscoring their abilities to be effective antibacterial substances from renewable sources. This study opens the door for more in-depth investigation into this topic by enhancing bimetallic nanoparticles and their utilisation in the biomedical field.

Polymer Inclusion Membranes (PIMs) have significantly advanced the field of membrane-based separation technologies introducing an innovative method for the selective transport and extraction of metal ions. The incorporation of ionic liquids (ILs) into PIMs leverages the exceptional characteristics of ILs to boost both selectivity and efficiency in the separation of metal ions. This synergy advances metal separation processes towards greener and more sophisticated solutions perfectly aligning with green chemistry and environmental sustainability. This review presents an overview of current knowledge on PIMs including the distinct roles of their different components. It critically assesses the different strategies essential for achieving optimal membrane performance and ensuring stability and selectivity of PIMs. Future research directions are discussed particularly focusing on the understanding of transport dynamics within PIMs and refining membrane compositions to reduce the risk of carrier leakage. These investigations promise to enhance the efficiency and environmental friendliness of metal ion separation propelling the field towards more effective and sustainable practices. This review can serve as a roadmap for ongoing research, promoting the advancement of IL-based extraction of metal ions via PIMs for sustainable and efficient metal separation processes.