RSC sustainability最新文献

Electrodes for supercapacitors were developed from activated carbon (GAC) derived from glutinous rice husk (GRH). The production of GAC involved the chemical activation of GRH with potassium hydroxide (KOH), followed by carbonization at 800 °C for 2 hours under a N₂ atmosphere. The pseudocapacitive effects of the GAC were enhanced through N/S doping by adsorption of methylene blue, followed by post-treatment. Two post-treatment methods were employed in this study: gamma irradiation at doses of 25 kGy (GAC-25), 50 kGy (GAC-50), and 100 kGy (GAC-100), and hydrothermal treatment (GAC-Hdt). Among all samples, GAC-25 exhibited the highest specific capacitance of 127.9 F g⁻¹ at 0.5 A g⁻¹, an 84.8% enhancement compared to GAC alone, attributed to pseudocapacitive effects. GAC-25 shows pseudocapacitor behavior, while GAC-Hdt shows EDLC characteristics at an increased scan rate. GAC-Hdt possessed a specific capacitance value of 0.5 A g⁻¹, about four-fold higher than that of GAC-25, due to its larger specific surface area of 1846 m² g⁻¹. These results highlight the potential use of gamma irradiation as an alternative post-treatment method for developing supercapacitor electrodes.

Phosphorus (P) is a vital element to enhance crop growth, but the excessive application of water-soluble P fertilizers has led to dwindling global P resources and elevated P levels in surface and ground waters. At the same time, high levels of P are excreted by livestock and poultry industries. These animal manures present an attractive source of secondary P, but the direct application of manures to farmlands may cause issues with P losses and environmental and health risks. To overcome this, pyrolysis (the thermal conversion of a biomass in oxygen-poor conditions) has been used in some situations without a full understanding of the impacts of the pyrolysis process on P forms and availability in the manure. This article critically reviews the use of pyrolysis to recover P from three types of animal manures (cow, swine, and poultry) in the form of biochars for applications in agriculture. Specific emphasis is paid to the P species in manures and their transformations during the pyrolysis process with the help of spectroscopic techniques (e.g., ³¹P NMR and XANES) and P fractionation schemes. The P concentrations, species, and availability are highly dependent on manure composition and especially pyrolysis conditions. During pyrolysis, the P is concentrated in the solid phase (biochar) and transformed into more inorganic (orthophosphate) and more crystalline forms as the pyrolysis temperature increases. Higher pyrolysis temperatures reduce the P extractability, which lowers the risk for P losses but may also affect plant P uptake. Strategies to modify P availability are presented and critical perspectives are given on the risks and limitations of manure-derived biochar application in agriculture.

Solvent usage is one of the most critical factors for the carbon footprint of the chemical and pharmaceutical industries. Therefore, finding suitable green solvents that can be sourced from biomass is necessary for more sustainable manufacturing processes. One of the greenest solvents is water, and chemical transformations in aqueous solution play an increasingly important role. To guide the search for suitable green solvents for extractions from aqueous solution, eleven biobased solvents were systematically evaluated with 132 absolute free energy calculations based on 1728 molecular dynamics simulations. These kinds of calculations are used in modern computer-aided drug discovery for protein–ligand binding because of their high accuracy and the ability to account for dynamic changes of heterogenous nanostructures. Based on the calculations, 1-butanol and cyclopentanol are recommended for extractions of hydrophilic molecules with a decadic logarithm of the partition coefficient between 1-octanol and water (log P) below 0.5, while cyclopentyl methyl ether and butyl methyl ether are recommended for hydrophobic solutes with log P > 2.6. Ethyl acetate and 1-pentanol are suitable for solutes in the mid-range. These findings are verified based on experimental extraction efficiencies from an aqueous solution in a micelle-enabled cross-coupling transformation. The extraction yields confirm the computational results, and also show that only the six most hydrophilic solvents lead to a clear phase separation in the presence of residual organic solvents and surfactants. This highlights that aqueous micellar media require special extraction solvents. Overall, both molecular level insight and practical considerations are needed for the selection of suitable green solvents.

Long-loop recycling of spent lithium-ion batteries is neither sustainable nor economical at scale. In the absence of design-to-recycle initiatives taken up by cell manufacturers, even for batteries produced today, all-in-one shredding processes are the only practical option to achieve circularity of critical materials. Shredding lithium-ion batteries ultimately produces ‘black mass’ – a low-value commodity comprising a mixture of graphite from the anode and lithium metal oxides from the cathode. Recovery of valuable metals such as cobalt and nickel from black mass using energy-intensive pyro- and hydro-metallurgy processes inevitably destroys the crystalline structure of lithium metal oxides and thus requires further resynthesis of battery material upon isolation and purification. This study presents an efficient process for direct separation of graphite and lithium metal oxides from numerous sources of black mass by utilizing a meta-stable oil-in-water emulsion. The purification of black mass is facilitated by one minute of high-power ultrasonic agitation followed by sieve separation, whereby the ultrasonic process enabling purification requires ca. 1% of the energy for heat removal of the binder. The separation exploits the disparity in hydrophobicity between graphite and lithium metal oxides, with ultrasonic energy enhancing the efficacy of the process to allow separation of cathode and anode counterparts with purity as high as 96% within minutes of operation. This innovative approach offers a promising solution for short-loop recycling of lithium-ion battery black mass.

Mn-doped Co₃O₄ supported on TiO₂ is a well-known Fischer–Tropsch Synthesis (FTS) catalyst. It has been shown that when the Mn doping exceeds 3 wt%, CO conversion drops and the product selectivity to alcohols and olefins increases dramatically. Here we examine the effect of the preparation method to determine how the proximity of the Mn in the as-prepared catalyst affects FTS performance. Three preparation procedures were examined: preparation of Mn doped Co(Mn)₃O₄ mixed oxides, surface doping of Co₃O₄ with Mn₃O₄ and a physical mixture of the two spinels. Characterisation studies including XRD, XPS and STEM-EDS, of the as-synthesised materials confirmed the successful preparation of spinel materials with crystallite sizes ∼20 nm. Surface enrichment of Mn on Co₃O₄ was seen in the as-prepared surface doped samples but not in the mixed oxide ones. STEM EDS studies revealed that after reduction Mn oxide had migrated to the surface in the mixed oxide samples similar to the surface doped samples. Subsequently, similar CO conversion and product selectivity was observed in both types of sample. However, unlike the surface doped and mixed oxide catalysts, the physically mixed oxide samples did not yield alcohols and olefins, although enhanced CO conversion was observed for the 3% physical mix. The results highlight the prevalence and importance of the effects of surface Mn doping on the Co speciation which leads to enhanced alcohol/olefin selectivity.

We have developed a kinetic model to investigate the post-plasma (afterglow) chemistry of dry reforming of methane (DRM) in warm plasmas with varying CO₂/CH₄ ratios. We used two methods to study the effects of plasma temperature and afterglow quenching on the CO₂ and CH₄ conversion and product selectivity. First, quenching via conductive cooling is shown to be unimportant for mixtures with 30/70 and 50/50 CO₂/CH₄ ratios, while it affects mixtures containing excess CO₂ (70/30) by influencing radical recombination towards CO₂, H₂ and H₂O, as well as the water gas shift reaction, decreasing the CO₂ conversion throughout the afterglow. This is accompanied by shifts in product distribution, from CO and H₂O to CO₂ and H₂, and the magnitude of this effect depends on a combination of plasma temperature and quenching rate. Second and more importantly, quenching via post-plasma mixing of the hot plasma effluent with fresh cold gas yields a significant improvement in conversion according to our model, with 258% and 301% extra conversion for CO₂ and CH₄, respectively. This is accompanied by small changes in product selectivity, which are the result of interrupted reaction pathways at lower gas temperatures in the afterglow. Effectively, the post-plasma mixing can function as a heat recovery system, significantly lowering the energy cost through the additional conversion ensued. With this approach, our model predicts that energy consumption can be lowered by nearly 80% in comparison to DRM under the same plasma conditions without mixing.

The deployment of nanoparticles (NPs) for targeted drug delivery in vivo holds immense potential for enhancing therapeutic efficacy while minimizing systemic side effects. However, the complexity of biological environments, including the biological barriers that need to be crossed for effective systemic delivery, presents significant challenges in optimizing NP delivery. This study demonstrates how a simple compartmental model facilitates the simulation and analysis of NP-mediated drug delivery, supporting targeted delivery optimization. The model involves reversible transport between five compartments related to drug delivery (administration site, off-target sites, target cell vicinity, target cell interior and excreta) that determine NP dynamics, including biodistribution, degradation, and excretion processes. This approach enables the estimation of delivery efficiency and the identification of critical factors affecting NP delivery through sensitivity analysis. A case study involving PEG-coated gold NPs delivered intravenously to the lungs demonstrates the model's capacity to describe observed biodistribution patterns and highlights key parameters influencing delivery outcomes. The model is exposed as a web application that provides a user-friendly graphical interface, enabling researchers to conduct in silico experiments with the goal of optimizing delivery strategies, thereby accelerating the development of precision nanomedicine. The model is made available both as a web application, via the Enalos Cloud Platform, and as a RESTful aaplication programming interface (API), providing a user-friendly graphical interface and programmatic access, respectively, enabling researchers to integrate the model into their own computational workflows. This study illustrates how simple compartmental modelling can be employed to guide the development of targeted drug delivery systems, contributing to more effective and personalized healthcare interventions.

The next generation is threatened by climate change, the significant impacts of global warming, and an energy crisis. Atmospheric CO₂ levels have surpassed the critical 400 ppm threshold due to significant reliance on fossil fuels to satisfy the increasing energy demands of our fast-progressing society. An overabundance of manufactured carbon dioxide (CO₂) emissions severely disrupts the ecology. The synthesis of methanol by the selective hydrogenation of CO₂ is a viable approach for generating clean energy and sustainably safeguarding our biosphere. Methanol is a versatile molecule with several uses in the chemical industry as an alternative to fossil fuels. The methanol economy is recognized as a pivotal development in the pursuit of a net zero-emission fuel, representing a crucial stride toward a more sustainable planet. The developing green methanol industry, or renewable methanol initiative, primarily relies on CO₂ adsorption and usage. This novel technique is essential for mitigating global warming. This review focuses on the synthesis of methanol utilizing noble metal-based catalysts and electrochemical reduction methods, examining the associated thermodynamic challenges and outlining future directions for research. It emphasizes the role of noble metals, including palladium, gold, silver, and rhodium, in enhancing catalytic activity and selectivity during the CO₂ to methanol conversion process. The incorporation of these sophisticated catalytic processes improves methanol production efficiency and facilitates novel methods for carbon capture and usage, therefore advancing a more sustainable energy framework.

The thermal degradation of the lignin contained in biomass, followed by catalytic upgrading of the resultant bio-oil, offers a promising renewable generation pathway for aromatic commodity chemicals, in particular benzene, toluene and xylene (collectively ‘BTX’). The primary barrier to widespread adoption of this technology is its economic unfavourability relative to petroleum-derived BTX production. Previous work has determined that iron-based zirconium oxide catalysts for the hydrodeoxygenation (HDO) upgrading step are able to selectively generate aromatic hydrocarbons (up to 12 wt%) and minimise catalyst coking. The techno-economic assessment (TEA) of a hypothetical industrial-scale biomass hydropyrolysis plant, converting 2000 tonnes per day of lignin waste into commodity chemicals using FeReO_x/ZrO₂ and Fe/ZrO₂ catalysed HDO respectively in scenario 1 (S1) and scenario 2 (S2), was investigated. The TEA was carried out by constructing a robust model that integrates both technical and economic aspects of the process. A Monte Carlo-type sensitivity analysis was then used to examine the sensitivity of the predicted earnings. With the yearly Cost of Manufacturing (COM) estimated to be 88/158 M£ per year and revenues predicted to be 116/171 M£ per year, the base-case processes were predicted to make a yearly gain of approximately 27.6 and 12.7 M£ per year respectively in scenarios 1 and 2, with the sensitivity analysis yielding gross earnings of approximately 65% (S1) and 95% (S2) of simulations. The variable to which the profitability was most sensitive was found to be the bio-oil yield, and maximisation of this yield is recommended as a focus of further research.

This study explores the initial industrial development of saccharification technologies, with a primary focus on hydrochloric acid (HCl) saccharification of biomass, particularly wood chips. It traces the historical progress from early 20th-century research to modern advancements, emphasizing the challenges, failures and successes in scaling up these processes. The work details the structural composition of wood, i.e. cellulose, hemicellulose, and lignin, and explains the mechanisms of their hydrolysis. Additionally, it reviews various methods for hydrolyzing wood chips into saccharides, including besides HCl-based methods also sulfuric acid hydrolysis, as well as other methods such as enzymatic hydrolysis and more recent technologies. This review highlights the industrial attempts to bring these technologies to scale, providing insights into the technological advancements and hurdles faced. As developers of Avantium's DAWN Technology, we introduce our optimized hydrochloric acid saccharification process, which enhances efficiency and addresses historical challenges. This comprehensive overview not only documents the historical and technical aspects of biomass saccharification but also underscores the importance of continued innovation in this field.