RSC sustainability最新文献

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This study proposes an innovative biorefinery concept, integrating microbial pretreatment (MBP), wet storage (WS), and mushroom cultivation to transform herbaceous biomass into high-value products, including biofuel pellets, Turkey tail mushrooms, and ethanol. This environmentally friendly approach reduces pretreatment times, economically delignifies lignocellulosic structures, and improves the durability and enzymatic digestibility of densified pellets. The biorefinery model includes five pellet-mushroom production facilities (Pellet Plant A) and one ethanol plant (Ethanol Plant A), strategically located approximately 140 km south of Saskatoon (50°53′16.1′′N, 106°42′15.5′′W) in the province of Saskatchewan, Canada, to minimize pellet transport distances. Pellet Plant A, with a capacity of 250 000 t per year, incurs unit production costs (UPC) of US$201–242 per t, primarily driven by the cost of fungal liquid inoculum preparation. These costs exceed those of conventional steam-explosion pellet plants, such as natural gas-fired (US$181 per t) and biomass-fired systems (US$166 per t). Consequently, ethanol produced at Ethanol Plant A, using these pellets, costs US$1.32 per L, compared to US$0.89 per L for centralized MBP straw bales-to-ethanol plants and US$0.57 per L for conventional dilute acid pretreatment plants. The economic viability of this biorefinery concept requires a minimum ethanol selling price (MESP) of US$1.03 per L and at least 50% farmer participation to achieve a positive net present value (NPV) without mushroom credits. However, integrating revenue from Turkey tail mushroom production significantly enhances financial outcomes, increasing Pellet Plant A's NPV by up to US$10 billion. This enables a reduction in pellet selling prices, lowering the MESP to US$0.77 per L with a pellet purchasing cost of US$100 per t. These findings demonstrate the economic feasibility and sustainability of this innovative biorefinery model, emphasizing the potential of combining microbial pretreatment technologies with diversified revenue streams.

Correction for ‘Carbon removal efficiency and energy requirement of engineered carbon removal technologies’ by Daniel L. Sanchez et al., RSC Sustain., 2025, https://doi.org/10.1039/d4su00552j.

Due to the increasing use of single-use plastics in daily life, plastic trash is expanding annually, destroying our ecology and producing an unparalleled waste disposal crisis. Bioplastics like poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) can substitute certain non-biodegradable polymer materials and can effectively biodegrade under predefined environmental conditions. Both PBS and PBSA were traditionally synthesized from petroleum resources, but in recent years, PBS and PBSA have been reported to be produced from a hybrid of petroleum and renewable resources. PBS and PBSA polymers have good ductility and strength, but their high production costs and limited production volume limit their widespread packaging usage. Therefore, they are usually blended with other polymers and fillers to improve processability, mechanical properties, and biodegradability. Thus, recent polymer processing advances have made these blends/composites an appealing material platform for packaging and agricultural applications with composting compliance. Despite this, few studies have investigated the application of these polymers in real food packaging uses and in agricultural applications, thus highlighting a research gap. Nevertheless, PBS and PBSA-based commercial items are currently on the market, with examples including flexible packaging materials, compostable cutlery, and disposable tableware. Therefore, the purpose of this article is to provide an overview of research trends on PBS and PBSA, including the sustainability of their green synthesis routes using LCA studies, their biodegradability, applications in food packaging and agriculture, and end-of-life considerations. This study aligns with the United Nations' sustainability goal of responsible consumption and production (Sustainable Development Goal 12).

Preparation of cyclic carbonates from CO₂ and epoxides via cycloaddition is a well-established synthetic route, which is not only economical but also in line with the atomic economy. To overcome the problem of the cluster formation of hydrogen-bond donors in functionalized poly(ionic liquid)s, which reduces their catalytic activity, a series of spacer-functionalized poly(ionic liquid) catalysts were developed. In poly(ionic) liquids, the hydrogen-donating effect enhances the intrinsic catalytic performance of the active sites and the long-chain alkyl groups prevent interactions between hydrogen-bond-donor groups, thus increasing the utilization of the active sites. Among the developed poly(ionic liquid) catalysts, the poly(ionic liquid) P[AC₁₂VIM][Br] containing amino groups demonstrated the highest catalytic activity (propylene oxide conversion up to 99%), which was comparable with that of bulky ILs. The best catalytic performance of P[AC₁₂VIM][Br] was attributed owing to its multiple functions in not only activating CO₂ and epoxides but also stabilizing Br⁻. Furthermore, the amphiphilicity of amino-functionalized poly(ionic liquid)s boosted their catalytic suitability for epoxide substrates with lipophilic edge groups, which was better than that of conventional poly(ionic liquid)s. Through XPS and NMR analyses, a mechanism of operation is proposed in which imidazole and hydrogen donor groups act co-operatively in epoxy during the reaction to assist in ring-opening. Thus, this study provides a new approach for improving the catalytic performance of poly(ionic liquid) catalysts from the viewpoint of an intrinsic reaction and utilization of the active sites.

To tackle global warming, the Paris Agreement (2015) strategically proposed achieving net-zero emissions of greenhouse gases (GHGs) by 2050 and limiting the global temperature rise below 2 °C. This requires a substantial reduction of all GHG emissions across all sectors over the next few decades. Methane has come into the spotlight as the second most potent GHG for its contribution to global warming. The Global Methane Pledge announced at COP26 (2021) proposed to reduce 30% of anthropogenic methane emissions by 2030 compared to the 2020 level. However, studies show that methane emissions will continue to increase even with the planned reductions and therefore the atmospheric methane concentration also. Effective methane removal technologies are urgently required for atmospheric methane remediation. This work evaluates the feasibility of atmospheric methane removal by enhancing the chlorine atom sink (i.e. a natural sink of methane in the lower troposphere) at a significant scale, considering that atomic chlorine initiates methane oxidation 16 times faster than the major natural methane sink of hydroxyl radicals in the atmosphere. Atomic chlorine is proposed to be generated by electrolysis of brine for chlorine gas followed by photolysis. This methane removal technology could be integrated with the state-of-the-art industrial chlor-alkali processes. Such integrated technology is evaluated for the potential of negative GHG emissions and their costs, with attention given to cost-efficient measures, i.e., the use of alternative renewable sources. A brief discussion is included on potential risks, side effects, benefits to the atmospheric methane remediation by 2050 and key required developments.

This paper shows the results collected in lab-scale experiments for photocatalytic H₂ evolution from rice industry wastewater, by using a cheap and eco-friendly graphitic carbon nitride catalyst, one-pot prepared by the sacrificial template method. The final effluent from the production of “rice milk” beverage proved to be really rewarding compared to pure water, highlighting the possibility of taking advantage of a sugar-rich matrix to boost H₂ formation. After preliminary experiments in glucose aqueous solution, yielding a maximum gas evolution above 1000 μmoles g⁻¹ h⁻¹, the study moved on to wastewater and the operational conditions were optimized through designed experiments, under simulated solar light. Production of about 150 μmoles g⁻¹ h⁻¹, at least 380-fold greater than production from neat water, was achieved by working with just 0.5 g L⁻¹ of catalyst directly in the raw effluent, thus limiting the amount of metal co-catalyst and avoiding sample dilution. The reproducibility of the process was good, with relative standard deviations below 12% (n = 3). The production was also verified under natural sunlight, obtaining a mean production of nearby 115 μmoles g⁻¹ h⁻¹. The sustainability of this photocatalytic setup is strengthened by the recyclability of the catalyst, which maintains its photoactivity for at least four treatments.

Tailoring the properties of the catalytic layer (CL) and its architecture is crucial for enhancing both the efficiency and selectivity of CO₂ electrolysers. Traditionally, CLs for CO₂ reduction comprise of a single binder material or a combination that handles both ion conductance and the maintenance of a hydrophobic environment. In this work, we decouple these processes into two individual, stacked catalyst-containing layers. Specifically, a hydrophobic catalytic layer is placed on the gas diffusion layer to improve water management within the CL during CO₂R in zero-gap electrolysers. Additionally, a second catalytic layer, bound by an ion-conducting binder, facilitates the conduction of OH⁻ and HCO₃⁻/CO₃²⁻ during CO₂R, thereby enhancing both ionic conductivity between the GDE and anion exchange membrane (AEM), as well as mechanical adhesion between different interfaces. Notably, we present a comprehensive stepwise optimization pathway for the CL, addressing both single and stacked CLs for CO₂-to-CO conversion at current densities of 300 mA cm⁻².

Solar thermochemical redox splitting of CO₂ using perovskite oxygen carriers in two-step cycles is a promising method for sustainable fuel production. In this study, a series of 23 potential perovskite candidates for CO production are designed, synthesized, and tested under the same experimental conditions. The material stability and the lattice structure are validated using Goldschmidt's tolerance factor and powder X-ray diffraction. For the reduction step, the high proportion of divalent cations (Sr²⁺/Ba²⁺/Ca²⁺) in the A site promotes oxygen transfer, and the maximum oxygen yield reaches 386 μmol g⁻¹ (δ = 0.164) for Gd_0.6Ca_0.4MnO₃. DFT calculation results indicate that the multi-cationic doping in La_0.5Sr_0.2Ba_0.15Ca_0.15MnO₃ shows a smaller energy barrier for oxygen transfer compared with the single A-site doping in La_0.5Sr_0.5MnO₃, with an oxygen vacancy formation energy of 2.91 eV per (O atom), and it offers the most favorable CO yields of 225 and 227 μmol g⁻¹ in two consecutive cycles. The designed La_0.25Gd_0.25Sr_0.25Ca_0.25MnO₃ further decreases the oxygen vacancy formation energy to 2.57 eV per (O atom). Based on the reaction rate analysis, the presence of B-site doping cations, such as in La_0.6Sr_0.4Mn_0.75Zr_0.25O₃ and La_0.5Sr_0.5Mn_0.8Ce_0.2O₃, increases the maximum oxidation rate, and the A-site multi doping of perovskites allows maintaining high CO production rates during the oxidation process. This work leverages tunable perovskite redox properties for enhanced CO production performance through DFT and thermochemical performance analysis, providing feasible guidance to promote CO₂ splitting by an active cation doping strategy.

This study introduces the concept and first demonstration of an effective molten carbonate chemistry for Direct Air Capture (DAC). Molten carbonate electrolysis is a high-temperature decarbonization process within Carbon Capture, Utilization and Storage (CCUS) that transforms chemistry transforming flue gas CO₂ into carbon nanotubes and carbon nano-onions. The key challenge for molten carbonate DAC is to split air's 0.04% CO₂ without heating the remaining 99.6%. This is accomplished by integrating a diffusive, insulating membrane over an electrolyte with a high affinity for CO₂.