RSC sustainability最新文献

Managing large volumes of food waste is a growing challenge. Eggshells (ESs) are an abundant and widespread waste that represent an interesting source for Ca-based materials. To fulfil the cradle-to-cradle sustainability concept, the final products need to be materials that can either degrade or serve as nutrients in soil. ES can be converted into different Ca precursors to obtain hydroxyapatite (Hap) nanoparticles, a promising solid fertilizer that can promote a controlled release of nutrients. Most of the reported procedures involve a high-temperature calcination step to obtain CaO, a process that is energy-intensive and CO₂ emitting. We propose an alternative by dissolving ES in an ascorbic acid solution, a green, non-toxic, and cost-effective reagent. Composition, crystallinity and morphology of the obtained product were compared to those of Hap obtained with commercial reagents and by dissolving ES in nitric acid. Nutrient release behaviour was evaluated through ICP-OES, demonstrating the material's potential for agricultural applications. This method offers a low-impact, circular approach to waste valorisation, promoting the conversion of food waste into high-value functional materials.

The global energy crisis caused by population increase and industrialization has prompted the exploration of more sustainable renewable energy sources. The utilization of organic and inorganic waste as an alternative energy source is emerging as a potential solution that can reduce dependence on fossil fuels. The present study investigates the thermogravimetric and physicochemical characteristics of blends derived from waste tires and coconut shells, emphasizing their viability as sustainable energy sources. Specimens consisting of different ratios of tire waste and coconut shells, designated as CS100WT0, CS75WT25, CS50WT50, CS25WT75, and CS0WT100, underwent analysis through thermogravimetric analysis (TGA), differential thermogravimetric analysis (DTG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and calorific value testing. The results demonstrate that augmenting the percentage of waste tires in the mixture significantly affects the thermal degradation, functional groups, crystalline phases, and calorific value of the material. The maximum temperature (T_max) reached by CS100WT0 was 325 °C, suggesting superior thermal stability compared to the other specimens. However, the T_max of CS75WT25, CS50WT50, and CS25WT75 increased as the content of waste tires increased. The incorporation of waste tires leads to a diminished intensity of the O–H functional group, indicating a reduction in moisture content and enhanced energy production efficiency. The calorific value of the specimens elevated with the elevated content of waste tires. The CS25WT75 specimen exhibited the highest calorific value of 27.75 MJ kg⁻¹, indicating that it has a higher energy potential compared to blends with a higher proportion of coconut shells. This research improves waste-to-energy technologies that mitigate pollution, promote resource recovery, and offer sustainable alternatives to conventional energy sources. This research is consistent with several Sustainable Development Goals (SDGs), specifically Goal 7, which focuses on Affordable and Clean Energy, and Goal 12, which emphasizes Responsible Consumption and Production.

We report here our study on the development of an efficient process to make 1,6-hexanediol from the hydrogenation of polycaprolactone assisted by ethanolysis. Using a ruthenium SNS pincer catalyst, a record high turnover number of 19 600 with 98% yield of 1,6-hexanediol is obtained at 80 °C and 60 bar H₂ pressure. The reported method has environmental advantages over the conventional process for the production of 1,6-hexanediol, which emits a significant amount of nitrous oxide greenhouse gas.

The development of effective technologies to remove microplastics (MPs) from both aquatic and terrestrial environments is an urgent necessity. As a proof of concept, here we show the catalytic degradation of polypropylene MPs and their transformation into chemicals using a permanently polarized novel metal-free bioceramic catalyst and sunlight.

Hyperbranched polymers exhibit distinctive properties attributed to their highly branched architecture and the abundant functional groups they carry. In this study, we synthesized innovative hyperbranched polyesters from vegetable oil derivatives without utilizing solvents. The reaction conditions were optimized and these polymers were comprehensively characterized based on size distribution, degree of branching and molecular structure. These hyperbranched polymers manifest as sticky viscous liquids with semi-crystalline behavior, featuring glass transition temperatures (T_g) and melting temperatures (T_m) as low as 18 °C. Subsequently, the latter were utilized as precursors for the design of unique thermosets with potential self-healing and recyclable pressure-sensitive adhesive properties.

In this study, we developed a new method for early-stage biodegradability assessment of cellulosic rheology modifiers (CRMs). Viscosity reduction was used as the primary indicator of polymer degradation. Complementary analyses included molecular weight changes (gel permeation chromatography, GPC), total carbohydrate content (TCC), and chemical oxygen demand (COD). Mixed microbial consortia from environmental sources ensured ecologically relevant conditions. Five CRMs including HPC-J (hydroxypropyl cellulose, J type), HPC-M (hydroxypropyl cellulose, M type), HPMC (hydroxypropyl methyl cellulose), HEMC (hydroxyethyl methyl cellulose), and cet-HEC (cetyl hydroxyethyl cellulose) were monitored over 8 weeks. Molecular weight dropped significantly, particularly for HPMC, which exhibited a 46.1-fold decrease, confirming chain scission. TCC declined sharply, with HPC-J surpassing an 85% reduction by day 56, evidencing microbial uptake. Furthermore, a predictive mathematical model was established, revealing the degradation sensitivity factor (‘a’), which ranged from a = 0.48 (for the highly resistant HPMC) to a = 4.85 (for the extremely sensitive cet-HEC). This simple, low-cost approach enables simultaneous small-scale testing as an early biodegradability screen, offering a practical decision tool before moving to standardized protocols and helping identify structural modifications that may hinder microbial breakdown.

Cancer therapy faces challenges including poor targeting, systemic toxicity, and inefficient drug release. To address these, we developed an eco-friendly drug delivery system using eggshell-derived calcium carbonate (CaCO₃). Porous C-PEG@ES nanoparticles were fabricated via PEG-assisted carbonization at 600 °C, exhibiting high specific surface area and pH-responsive drug release. In an acidic tumor microenvironment (pH 5.5), CaCO₃ decomposition enhanced oxaliplatin release, showing 2.3-fold higher efficiency than at pH 7.4. The system also raised environmental pH from 5.2 to 6.2 within 15 hours, modulating the tumor microenvironment and promoting apoptosis. Cytotoxicity tests confirmed its biocompatibility and antitumor efficacy, offering a sustainable and precise therapeutic strategy with reduced systemic toxicity.

The benchmark Zr-terephthalate MOF UiO-66 is typically prepared by solvothermal synthesis in N,N-dimethylformamide (DMF), one of the few solvents able to dissolve terephthalic acid. The use of DMF is one of the major drawbacks for the transfer of UiO-66 to large-scale applications, since DMF is an expensive and toxic organic solvent. In this work, we propose a water-based route to synthesise UiO-66 using either dimethyl terephthalate or bis(2-hydroxyethyl) terephthalate, which can be obtained from chemical recycling of waste polyethylene terephthalate, as a source of the linker. Hydrochloric acid and acetic acid were used as modulators during the synthesis to control the kinetics of ester hydrolysis and MOF crystallisation, aiming to avoid the collateral precipitation of terephthalic acid. A chemometric design of experiments was employed to optimise the reaction parameters, showing that 15 molar equivalents of hydrochloric acid enable hydrolysis without inhibiting crystallisation, while acetic acid controls which phase is obtained, favouring the desired face centred cubic topology at 15 molar equivalents. The optimised conditions afford UiO-66 with high crystallinity and porosity in just 2 hours at 90 °C. A crucial role in the process is played by the monoester, which is more soluble than both the diester and the diacid in the reaction environment and can be involved in the formation of secondary building units. We also developed a DMF-free workup protocol based on the use of ethanol/dimethylsulfoxide mixtures and water. A 50-fold scale up (500 mL) was demonstrated using a round bottom flask, producing UiO-66 with properties comparable to the product of the small-scale synthesis and with a space-time yield >200 kg m⁻³ d⁻¹.

We thank Wu and Criddle for their commentary and welcome this scientific dialogue. Our approach was designed to rigorously assess the potential for insect-mediated expanded polystyrene (EPS) degradation by comparing pure and commercial EPS under controlled conditions that eliminated cannibalism artifacts. Our results demonstrate that mealworms mechanically fragment EPS but achieve no genuine biochemical degradation. Pure EPS remained chemically unaffected after gut passage, while commercial EPS showed only modest additive-mediated oxidative changes, and not enzymatic polymer backbone cleavage. Additional studies on superworms (Zophobas morio) with both EPS and polyvinyl chloride (PVC) yielded corresponding results, confirming that the absence of plastic metabolism spans multiple insect species and polymer types. Here we address Wu and Criddle’s concerns regarding mass balance, isotopic interpretation, and analytical methods while demonstrating how experimental artifacts in previous studies generate false evidence for biodegradation. Simple scalability calculations reveal the fundamental impracticality of any insect-based approach: treating one ton of polystyrene would require over sixty million mealworms, producing more than four tons of dead biomass while generating vast quantities of microplastics and achieving zero meaningful degradation. Our controlled methodology establishes that insect-mediated plastic treatment is neither chemically viable nor economically feasible.

Carbon dots (CDs) have garnered significant attention since their discovery in 2004. Their excellent optoelectronic properties, superior biocompatibility, and ecological friendliness make them very promising for sustainable agricultural applications. In this review, the synthesis strategies of CDs are first summarized and the photoluminescence mechanisms, with a specific focus on linking these fundamentals to their functions in agricultural production, are elucidated. Then the diverse applications of CDs in agriculture are detailed, specifically highlighting their roles as photosynthetic efficiency enhancers, light-conversion films and LEDs for controlled-environment agriculture, and versatile nanosensors for detecting critical agricultural metrics. Finally, the current challenges and prospects of CDs are discussed to guide their further innovative exploration in agriculture.