RSC sustainability最新文献

The textile chemical processing industry is one of the most polluting industries. The water and energy consumption in textile wet processing is very high and produces vast amounts of effluent. Desizing, scouring, bleaching, and mercerising are the essential processes involved in textile pretreatment. A novel photocatalytic technique is implemented to minimise the consumption of energy, water and time in a combined desizing and scouring process. The industrial woven cotton grey fabric is treated with an oxidising agent in the padding method and irradiated under ultraviolet-C (UVC). Then, the UVC-exposed fabric is washed at a lower temperature than that used in conventional washing. Furthermore, the scoured fabric is dyed with reactive dyes to study its dyeability. This technique saves 79% of the processing time and is superior to the conventional process in terms of dyeability. The water and energy consumption of the demonstrated process is reduced by 71% and 72%, respectively. The fabric properties are analysed using weight loss, tensile strength, absorbency time, whiteness, colour value, colour fastness, FTIR, WXRD, SEM, and EDX. Life cycle analysis is also conducted.

Metal–metal hydroxide/oxide interface catalysts are valued for their multiple active sites, enabling synergistic reactions in close proximity for advanced catalytic applications. Herein, we present a highly efficient and sustainable method for synthesizing amides through oxidative amidation reactions involving aldehydes and secondary amines. The method utilizes tert-butyl hydroperoxide (TBHP) as the oxidant in THF at 90 °C and employs well-defined nanoscale heterojunctions of zinc oxide, nickel oxide, nickel [ZnO–NiO–Ni] (ZN-O-A-7) as a recyclable heterogeneous catalyst. The ZnO–NiO–Ni heterostructure and their synergistic cooperation are crucial for enhancing the efficiency and selectivity of the oxidative amidation reaction. The versatility of the methodology was demonstrated with diverse aldehyde derivatives and secondary amines, including morpholine, thiomorpholine, piperazine, pyrrolidine, and piperidine. Mechanistic investigations via controlled experiments provided insights into the underlying processes. The catalyst demonstrates ease of synthesis, use of stoichiometric amounts of oxidant, excellent selectivity, high functional group tolerance, applicability to various aldehydes and amines, multiple reusability, and potential for large-scale processes. These features collectively enhance the economic and sustainable nature of both the catalyst and the protocol, making a valuable contribution to the field of catalytic amidation reactions.

The development of electromagnetic interference (EMI) shielding composites with tunable frequency-selective shielding attributes is of critical importance for their applications in military and signal detection fields. This study introduces a multilayered conductive polymer composite comprising waste polyurethane foam (WPUF), ground tire rubber (GTR) powders, carbon nanotubes (CNTs) and cellulose nanofibres (CNFs). The bulky waste polymeric material with a porous structure, WPUF, is utilized as the substrate to construct the rationally designed alternative conductive-insulating multilayered structure, which significantly enhances the multiple-reflection of the incident EM wave. This conductive composite provides enhanced EMI shielding effectiveness and unique tunable frequency-selective EM shielding performance. The EMI shielding peak shifts with the variation of CNTs, and adjusting the GTR/WPUF ratio in the insulating layer enables fine-tuning of its selective EMI shielding performance over a specific frequency range. In addition, the composite demonstrated robust durability, which benefits its practical application. This approach proposes a practical and innovative method for the design and fabrication of advanced frequency-selective EMI shielding composites with bulky polymer wastes.

At present, phosphorus-doped porous carbon–oxygen reduction catalysts prepared by chemical methods are not able to achieve good performance. In order to improve the catalytic performance of the phosphorus-doped oxygen reduction reaction (ORR), wild Angelica dahurica (WAD) with abundant phosphorus was used as a carbon carrier and phosphorus source at the same time. Phosphorus-doped carbon-based materials based on carbonization of biomaterials also had a homogeneous structure and excellent stability. WAD directly carbonized at 900 °C (WAD-900) had a half-wave potential of 0.822 V relative to a reversible hydrogen electrode, a limiting current density of 4.54 mA cm⁻² at 1600 rpm, an average number of transferred electrons of four, and a stability of 95.9% for 20 000 s, larger than the 82.6% of Pt/C. This study demonstrates the excellent performance of naturally occurring phosphorus dopants in oxygen reduction reactions and their favorable catalysis properties, opening up a new direction for chemical dopants that find it difficult to achieve good performance.

Hydrothermal processes, such as hydrothermal liquefaction (HTL), are widely used for converting biomass into fuel and chemicals using superheated water as the processing medium. However, conventional organic solvents are often utilized in these processes, raising potential concerns about their environmental impact. For example, dichloromethane (DCM) is commonly used in HTL processes due to its ability to effectively extract organic molecules from the aqueous phase. Alcohols such as ethanol, 1-butanol and non-renewable tetrahydrofuran (THF) have also demonstrated positive effects as a co-solvent with water in biomass conversion. 2-Methyltetrahydrofuran (2-MeTHF) is recognized as a green solvent and is often used as a bio-renewable substitute for DCM and THF in low-temperature transformations. In this comparison study, we explored the potential of 2-MeTHF as a recovery agent and co-solvent in the HTL of several major examples of waste biomass, namely herb residues, paper towel and sawdust. In this investigation, we compare 2-MeTHF with other solvents as extractant and co-solvent in HTL processes. Our research demonstrates that 2-MeTHF is an exceptional option for biocrude extraction, surpassing DCM and consistently producing considerably higher biocrude yields for HTL under several identical conditions (e.g. atmosphere and pH) without lowering the quality of the biocrude products to any significant extent. When utilized as a co-solvent, 2-MeTHF significantly improved biocrude yields, generally outperforming ethanol, 1-butanol and THF while maintaining or enhancing their quality.

Clean and safe water is a vital resource for human life. To ensure that consumable water is bacteria-free, water treatment, including the widely used chlorination process, is performed. Free chlorine resulting from the chlorination process in consumable water is a dangerous analyte and it is one of the vital parameters in water quality monitoring. Global guidelines state that free chlorine in consumable water should be controlled at 0.2–5.0 mg L; deviations from this concentration range could cause consumers to suffer from dire health effects. To control the concentration within the said range, various methods for free chlorine monitoring have been developed in recent years, categorized into conventional, optical and electrochemical methods. However, limitations such as high cost and complexity of analysis prevent these conventional methods from meeting the “Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free and Deliverable to end users” criteria for diagnostic tests set by the World Health Organization. Paper-based methods are therefore introduced to replace the conventional methods in the hope of meeting the criteria. However, the paper-based methods are still confined to the lab scale and are highly dependent on chemicals for the detection of free chlorine. Therefore, the capabilities of carbon quantum dots are introduced as a suitable indicator for free chlorine measurement. Using carbon quantum dots as an indicator is recommended for the future development of sustainable portable paper-based sensors due to their excellent absorption and fluorescent properties; in addition, carbon quantum dots can be synthesized from natural resources.

In recent years, utilization of biopolymers as natural coagulant–flocculant (CF) systems has become an area of interest, due to their sustainable nature (renewable, biodegradable, and non-toxic) and potential utility as alternative systems to replace synthetic flocculants. Herein, a biopolymer extracted from Aloe vera mucilage (AVM) was investigated for its arsenic(V) removal properties in a CF water treatment process. Structural characterization of AVM was supported by spectroscopy (FTIR, ¹³C solids NMR & XPS), TGA, rheology, and pH_pzc. The arsenic(V) removal process was optimized by employing the Box–Behnken design under three main factors (coagulant, flocculant dosage and initial arsenic(V) concentration), which led to a reduction of the initial arsenic(V) concentration to levels below the Maximum Acceptable Concentration (MAC; 10 μg L⁻¹). The kinetics and thermodynamics of arsenic(V) removal were analyzed with a one-pot in situ method, where the kinetic profiles followed a pseudo-first-order model. The thermodynamic parameters are characteristic of a spontaneous (entropy-driven) and endothermic physisorption removal process. Flocs isolated from the process were analyzed by XPS, where the results reveal that calcium and amide groups of AVM contribute to the arsenic(V) removal mechanism.

Protein-based materials are biocompatible and have a variety of remarkable properties; consequently, they are finding more and more applications. Nature recycles proteins in multiple ways, ranging from bio-degradation (a slow approach) to fast recycling of protein metabolism. The latter is a wonderful example because a random mixture of proteins gets digested into amino acids (AAs), the fundamental building blocks of proteins. These AAs are then used by cells to produce whichever protein is needed at the time of synthesis. Seen through the lens of recycling, this process transforms a random mixture into something not necessarily present at the start but needed at the moment of recycling. We have recently shown that the process of protein recycling can be performed in vitro and called it NaCRe (Nature Inspired Circular Recycling). In a previous NaCRe proof-of-concept experiment, we started with various protein mixtures but were able to produce only small quantities of recycled protein, in the microgram scale. Here, we show that NaCRe can be used to convert milligrams of a protein mixture containing one of the most common protein materials (silk) into a milligram of an hydrogel made of green fluorescent protein (GFP). We show that in order for NaCRe to be efficient the starting protein mixture must contain a good balance of all AAs and discuss the challenges encountered when scaling up NaCRe.

An improved synthesis of the pinene-derived monomers (3-pinanyl acrylate 1 and 3-pinanyl methacrylate 2), replacing hazardous and/or expensive reagents from established methods with cheaper, more innocuous and sustainable reagents, is reported; the monomers of high purity are obtained at up to 160 g scale, without the need for chromatographic separation. Subsequently, these monomers (1 and 2) were successfully copolymerized with n-butyl acrylate/methacrylic acid or styrene/methacrylic acid using a radical semi-batch emulsion copolymerization process. For comparison, materials incorporating the more established terpene-derived monomer iso-bornyl methacrylate 3 were also prepared in an analogous fashion. The obtained polymer latexes had particle sizes between 65 and 90 nm and very low polydispersities (<0.08) and were stable for several years without any coagulum formation. Gradient liquid chromatography indicated that all copolymers had relatively uniform chemical composition distributions. The n-butyl acrylate containing copolymers (P1–P3) were obtained with high molar masses (M_n > 40 000 and M_w > 400 000), very high dispersities (Ð > 9.5), and low glass transition temperatures (T_g < −5 °C). The styrene-based copolymers (P4–P6) had slightly lower molar masses (M_n > 40 000 and M_w > 150 000), lower dispersities (Ð > 3) and high glass transition temperatures (95 °C < T_g < 120 °C). Preliminary testing of the n-butyl acrylate-based materials demonstrated the potential of these copolymers for use in coating applications. The poly(n-butyl acrylate)/pinanyl methacrylate copolymer P2 was found to be harder (König hardness) and had better stain resistance properties towards water-based substances than the analogous n-butyl acrylate-based copolymers containing 3-pinanyl acrylate (P1) or iso-bornyl methacrylate (P3). Through further refinement of the copolymerization process we expect that the properties of these polymers may be further tailored towards a range of coating applications.

While retaining wood morphology and characteristics, i.e., growth rings and brown color, biological cushioning materials were successfully fabricated by the partial removal of lignin and hemicellulose from Cryptomeria japonica wood during an ionic liquid-based sustainable chemistry approach.