RSC sustainability最新文献

Water eutrophication caused by excess nutrients can be addressed by applying layered double hydroxide (LDH) materials. The LDH structure is based on positively charged layers and negatively charged counterions between the layers, or solvent molecules, which are optimal for phosphate removal. The M²⁺ : M³⁺ molar ratio and the synthesis method employed affect LDH properties. LDH materials are synthesized using co-precipitation, urea hydrolysis, hydrothermal treatment, and sol–gel methods. The phosphate adsorption performance of different LDH materials is compared, focusing on Al, Fe, and La, as well as Zn, Mg, and Ca. The role of LDH composites is highlighted. Different optimization parameters, including dosage, contact time, pH, initial concentration, reusability, temperature, and the influence of co-existing ions, are discussed. Interactions such as electrostatic attraction (ES), ion exchange (IX), ligand exchange (LX), ligand complexation (LC), surface complexation (SC), hydrogen bonding (HB), and π–π appear to be the main mechanisms of phosphate adsorption by LDHs. Thus, the need for low-cost and efficient systems for phosphate recycling underscores the promise of tunable LDH composition for selective phosphate adsorption as LDH materials have demonstrated sustained performance, verifiable regeneration, successful real-world piloting, scalable supply, and regulatory standards consistent with the circular economy.

Correction for “Green initiatives for the synthesis of polyamide monomers: precision fermentation using engineered Corynebacterium glutamicum and extraction of purified 5-aminovaleric acid (5AVA) and putrescine” by Keerthi Sasikumar et al., RSC Sustainability, 2025, https://doi.org/10.1039/d5su00799b.

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.

Anaerobic digestion (AD) is a process for valorizing sewage sludge through biogas production from sludge that is processed in water resource recovery facilities (WRRFs). Biogas can be combusted to generate thermal and electrical energy, converting the methane component of biogas into near-neutral carbon dioxide emissions of biogenic origin. Sewage-derived biogas is comprised of ≈98% biogenic carbon as methane and carbon dioxide. The capture of carbon dioxide of biogenic origin offers an opportunity to generate negative carbon emissions to offset the greenhouse gas (GHG) emissions from biogas production and utilization processes. In this work, an inventory of estimated GHG releases from AD system emissions and leaks in WRRFs across Canada was estimated with open-source data. The potentials to deploy different carbon capture processes to achieve carbon-neutral biogas systems were then estimated. The results show that implementing carbon capture systems downstream from biogas utilization or in biogas upgrading units could offset the carbon footprint of biogas generation systems. Implementing in-digester carbon capture would result in partial net GHG emission reduction. Moreover, some carbon capture processes would result in a surplus of negative GHG emissions with potential to offset the GHG emissions from other waste management activities, such as incineration.

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.