RSC sustainability最新文献

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.

Synthetic fibers in the market are mainly derived from fossil resources. The depletion of these resources and the accompanied environmental issues have stimulated interest in the utilization of renewable materials. Cellulose, which is widely available in lignocelluloses, is a type of abundant and renewable biopolymer in nature. It has been ascending as a promising feedstock for the manufacture of functional materials to replace fossil-based synthetic fibers. Pretreatment of lignocelluloses is a requisite step for the production of cellulosic materials since this biopolymer is embedded in a matrix composed of lignin and hemicellulose in the plant cell wall. However, cellulose degradation usually occurs during the pretreatment and subsequent material preparation processes, affecting the properties of the fabricated materials. In this study, we provide a comprehensive review of the strategies to inhibit cellulose degradation in the valorization of lignocelluloses for the fabrication of functional materials. It is demonstrated that the interactions between the solvent (including organics, ionic liquids, and deep eutectic solvents) and cellulose are closely related to its degradation. Specifically, too strong interactions would lead to the degradation of this biopolymer, resulting in a decrease in the degree of polymerization of cellulose, which leads to inferior properties (including mechanical properties) of the corresponding materials. Introducing additives, co-solvents, and radical scavengers or the selection of appropriate solvents affect the interactions between the solvent and cellulose, thereby inhibiting degradation and facilitating the fabrication of functional materials with excellent properties. The challenges and future perspective (e.g., understanding the inhibition mechanism at the molecular level) in the development of more efficient technologies to prevent cellulose degradation are also highlighted. This study can provide guidance for the design of systems to obtain cellulosic materials with excellent properties, encouraging more researchers to engage in this field to promote relevant progress.

Biodegradation of commercial expanded polystyrene foam (EPS) and pure EPS foams was investigated by Tahroudi et al. (2025) with a single source of mealworms (larvae of Tenebrio molitor) from Australia. They claimed that EPS is not chemically degraded by yellow mealworms because degradation of the additive was solely responsible for the molecular weight reduction of commercial EPS, and pure EPS was essentially unaffected by passage through the digestive tract. They found that both pure and commercial EPS diets failed to sustain mealworm growth, and survival rates decreased, which has been documented by other researchers. Our comments are that the conclusions of Tahroudi et al. i.e. “expanded polystyrene is not chemically degraded by mealworms” were not fully supported by their data and key evidence was overlooked due to methodological limitations and other weaknesses, including an incomplete mass balance, misinterpretation of GPC and FTIR data, and underutilization of analytical tools established for assessment of plastic degradation. Published results, including our own, demonstrated polystyrene biodegradation of both commercial foams and high-purity PS products by mealworms from various sources. Degradation capabilities varied by mealworm strain, larval age, physical and chemical properties of PS products, nutrients, and environmental factors, making broad generalizations problematic. We also call for microbiome, transcriptome and metabolome analyses to better understand enzymatic contributions to plastic biodegradation. Given the growing body of evidence supporting mealworm-mediated plastic degradation, we highly recommend a more comprehensive approach to assessing plastic biodegradation, incorporating long-term studies, CO₂ release, advanced analytical techniques (¹H NMR, GC-MS, py-GC/MS, δ¹³C, XPS etc.) with mass balance calculations associated with gut microbiome, transcriptome and metabolome. Comparison of mealworms from different sources, nutrition history and feeding conditions, and instar stage would provide new insights into the mealworm-mediated plastic degradation.

The demand for bio-based epoxy thermoset alternatives within the adhesive industry has seen substantial growth in recent years. This increase is attributed to a heightened exploration of renewable materials, including biopolymers and monomers derived from renewable resources. However, despite these significant advancements, a considerable portion of the research primarily focuses on edible oils, which may inadvertently neglect critical implications for food security. So, this study explores the thermal, mechanical, and adhesive properties of epoxy thermosets derived from biobased epoxidized Thevetia peruviana oil (ETPO) cured with two diamines, 1,10-decane diamine (DDA) and m-xylene diamine (XDA), using imidazole (IM) as a catalytic initiator. The thermosets were evaluated for lap shear strength on stainless steel (SS) and aluminium (Al) substrates at varying imidazole concentrations (0–5%) and curing times (24–96 hours). The results show that DDA-cured thermosets demonstrate superior thermal stability and heat resistance, with T_5% increasing from 149 °C to 256 °C and T_HRI from 139 °C to 162 °C as IM concentration rises. XDA-cured thermosets exhibit higher adhesive strength, peaking at 1.47 MPa on SS at 5% IM and 72 hours, but lower thermal stability, with T_5% values decreasing from 157 °C to 68 °C. Imidazole's catalytic efficiency enhanced the crosslinking in both systems, with DDA providing better thermal stability and XDA delivering higher adhesive strength. These findings demonstrate the potential of ETPO-based thermosets as sustainable adhesives, offering excellent performance for industrial applications.

Renewable energy for green hydrogen production presents a promising avenue for sustainable energy storage. However, the increasing demand for green hydrogen may strain freshwater resources. The direct electrolysis of seawater is considered an alternative, but high anion concentration in seawater poses challenges. This study focuses on testing cost-effective electrocatalysts for the oxygen evolution reaction (OER) to facilitate hydrogen generation from seawater electrolysis. The investigation of electrodeposited nickel-iron hydroxide (NiFe(OH)₂) on a microelectrode in alkaline seawater solutions shows promising results for achieving low overpotentials at high current densities. In alkaline simulated seawater (1 M KOH and 0.5 M NaCl), the electrode exhibited low overpotentials of 278 and 305 mV at 333 K, to reach current densities of 500 and 1000 mA cm⁻², respectively. Furthermore, in alkaline natural seawater, the electrode exhibited low overpotentials of 347 and 382 mV at 333 K, to reach 500 and 1000 mA cm⁻², respectively. To deliver a current density of 2000 mA cm⁻², the catalyst requires overpotentials of only 341 mV in 1 M KOH and 0.5 M NaCl solution and 409 mV in alkaline Absolute Ocean, a standardised seawater solution. Overall, the findings from this study provide a benchmark to contribute to the understanding of an effective, low-cost, easy-to-synthesize OER catalyst for seawater electrolysis, offering a practical solution for hydrogen generation.

The limited photocatalytic performance of individual metal–organic frameworks (MOFs) restricts their practical use. To address this, the integration of distinct MOFs into MOF-on-MOF heterostructures can create well-defined charge-transfer interfaces, significantly enhancing photocatalytic efficiency. Motivated by this, we investigated the in situ assembly of ZIF-67 with NH₂-MIL-125(Ti), resulting in a binary ZIF-67/NH₂-MIL-125(Ti) all-solid-state Z-scheme heterostructure. Comprehensive characterisation through PXRD, BET, FTIR, UV-Vis spectroscopy, contact angle analysis and electrochemical studies confirmed enhanced structural and optoelectronic properties. Elemental profiling was carried out by ICP-OES, CHNO evaluation, and EDX spectroscopy. The hybrid catalyst exhibited an impressive H₂O₂ formation efficiency of 1345 µmol g⁻¹ h⁻¹, accompanied by a quantum yield of 3.64% under 400 nm irradiation, and also delivered a H₂ evolution output of 215 µmol h⁻¹, each showing a fourfold improvement compared to the individual pristine MOFs. The synergistic interaction between the well-designed MOF-on-MOF heterostructure and the Z-scheme charge transfer mechanism effectively minimised charge recombination, as evidenced by XPS, PL spectra, TRPL, and EIS analyses. Furthermore, free radical trapping experiments and ESR studies confirmed the critical role of ˙O₂⁻ radicals in the photocatalytic formation of H₂O₂. This study provides valuable insights for developing advanced MOF-based heterojunction photocatalysts tailored for efficient solar-to-chemical energy conversion.

Lactose as a primary carbon source for fermentation is not as thoroughly investigated as glucose, despite certain advantages such as potential sourcing from high volume dairy side-streams. We investigated whether lactose could be a feasible feed source for various lactic acid bacteria (LABs) to produce lactic acid (LA), which is a precursor for the synthesis of the bioplastic polylactic acid. In 1 Litre stirred tank bioreactors under microaerophilic batch growth conditions Lactiplantibacillus plantarum ATCC 8014 had the highest LA titre (40 g L⁻¹) and productivity (0.83 g L⁻¹ h⁻¹) compared to other LABs tested. When air was supplied to the bioreactor at 10% dissolved oxygen, L. plantarum ATCC 8014 fully consumed the lactose supplied to produce 40 g L⁻¹ LA and increased the LA volumetric productivity to 1.51 g L⁻¹ h⁻¹ in 28 hours. Fed-batch fermentations with L. plantarum ATCC 8014 achieved the highest LA titre (69.05 g L⁻¹) but productivity was reduced (1.28 g L⁻¹ h⁻¹) compared to the best batch cultures. Under continuous culture conditions (D = 0.1 h⁻¹) L. plantarum ATCC 8014 had the highest LA yield (0.88 g g⁻¹) from lactose but the titre was low (4 to 6 g L⁻¹) and productivity was not stable.

Global environmental challenges including environmental pollution, water scarcity, and climate change are negatively impact the standard of living for humans on the Earth. Research and development in the field of water treatment paved the way for the utilization of sustainable materials for water purification, and the currently available innovative technologies are capable to purify water as per the standards put forward by World Health Organization. However, the cost of such technologies is very high, making them unaffordable for the global population. Environmentally friendly and biodegradable materials are of high demand for water purification. In this context, biocarbon is a suitable material, which exhibits peculiar properties such as low cost, natural abundance, eco-friendliness, and easy processability. As per the Sustainable Development Goals (SDGs) set by the United Nations, the SDG 6 deals with clean water and sanitation. Purifying the contaminated water resources using biocarbon has gained great interest in the recent past as a suitable solution to meet the global freshwater requirement. A review report in the field of biocarbon-based water purification is lacking in the literature, which has motivated us to write a review on biocarbon-based sustainable water purification. We discuss the synthesis, properties, and water remediation measures of eco-friendly biocarbon and biocarbon-based materials. This review opens up a new paradigm shift in water purification technologies, which are sustainable, eco-friendly, and cost-effective compared with the currently available technologies.