RSC sustainability最新文献

As industries face increasing societal and governmental pressures to adopt sustainable practices, the methanol (MeOH) and ammonia (NH₃) sectors, significant contributors to greenhouse gas (GHG) emissions, are seeking innovative solutions to transition toward net-zero emissions. Here, we report on the use of industrial symbiosis (IS) as a transformative strategy to facilitate the cleaner co-production of MeOH and NH₃ by integrating green hydrogen (H₂) within a carbon capture and utilisation (CCUS) flowsheet. We examined the environmental assessment of various co-production pathways across a system boundary, which includes three (3) leading technologies – Steam Methane Reforming (SMR), Autothermal Reforming (ATR) and Gas Heated Reforming (GHR), considering both business-as-usual (BAU) and hybrid IS integration (Hyd). MeOH flowsheets utilised all three technologies, while NH₃ production employed SMR and ATR systems. This comprised six (6) BAU MeOH and NH₃ co-production schemes (GHR–SMR_BAU, SMR–SMR_BAU, ATR–SMR_BAU, GHR–ATR_BAU, SMR–ATR_BAU, ATR–ATR_BAU) and six (6) Hyd (GHR–SMR_Hyd, SMR–SMR_Hyd, ATR–SMR_Hyd, GHR–ATR_Hyd, SMR–ATR_Hyd, ATR–ATR_Hyd) cases, utilising cradle-to-gate life cycle assessments (LCA). Results show that IS-integrated flowsheets reduced GHG emissions by 12–28% compared to BAU operations, with GHG impacts improving in the order GHR–ATR_Hyd > ATR–ATR_Hyd > SMR–ATR_Hyd > GHR–SMR_BAU > ATR–SMR_BAU > SMR–SMR_BAU, in agreement with energy and resource efficiency results. Notably, the GHR–ATR_Hyd configuration outperformed all other cases, reducing natural gas consumption by 11% and heating requirements by 8.3%. Furthermore, sustainability results support IS as a pathway to environmental benefits-with ATR-based NH₃ operations achieving up to 31% improved impacts linked to both ecosystem quality and human health. Ultimately, our study underscores the critical role of IS in advancing resilient, low-carbon practices, promoting sustainable technologies for net-zero emissions and defossilisation, thereby supporting a transformative shift towards sustainable industrial operations.

Deep Eutectic Solvents (DESs) have become emerging green solvents within sustainable development and environmental protection. Characterized by their low toxicity, cost-effectiveness, environmental sustainability, and versatility, DESs are increasingly utilized across diverse sectors. Notably, in materials synthesis, these solvents offer the advantages of biodegradability and recyclability, bypassing high-temperature and high-pressure synthesis conditions, thus reducing environmental hazards and energy consumption while enhancing material performance. Consequently, adopting DESs as reactive or nonreactive media in nanomaterial synthesis has attracted significant attention. However, there are still knowledge gaps addressing the roles of DESs in developing and functionalizing advanced materials. This review regards these gaps by elucidating the unique chemical, thermal, and electrochemical properties of DESs. It then explores their recent applications in nanomaterial fabrication and discusses how DESs regulate material synthesis using three typical strategies, including chemical, thermal, and electrochemical processes. Additionally, it outlines the potential, key challenges, and limitations of using DESs in materials science. By providing a comprehensive analysis, this review aims to deepen understanding of DESs, broaden their use, and enhance their integration into materials synthesis practices.

5-(Chloromethyl)furfural (CMF) has received enormous interest over the past two decades as a carbohydrate-derived platform chemical for synthesizing organic chemicals of commercial significance. This work reports a general synthetic protocol for synthesizing several known and novel mono- and diesters of CMF with potential applications as chemical intermediates, neutral surfactants, and plasticizers. The functional groups on CMF were selectively activated using relatively innocuous reagents, and the products were isolated with satisfactory yields (79–90%). The three-step process starts by oxidizing the aldehyde group into a carbonyl chloride using tert-butyl hypochlorite as a selective oxidant. The resulting carbonyl chloride was reacted with an alcohol reagent in the same pot to form the monoesters. The chloromethyl group was then reacted with the triethylammonium salt of a carboxylic acid by a nucleophilic substitution reaction to prepare the diesters. The reactions were optimized for temperature, molar ratio of reagents, and solvents. Depending on the choice of alcohol and the carboxylic acid reagents, the mono- and diester products can be made entirely biorenewable.

The release of plastics into the environment is a pressing issue of the modern society, and the identification of strategies for their recycling is a challenge in chemical research. This work analyses the possibility of combining the efficiency of task-specific ionic liquids (TSILs) with the effect of ultrasound irradiation (US) to perform the alcoholysis of polycarbonate (BPA-PC). Aliphatic cations were combined with environmentally friendly basic anions to obtain TSILs able to perform the process at room temperature. Different operational parameters were optimized. The process performance was evaluated using a holistic approach to green chemistry, and the best catalysts were tested for their cytotoxicity toward two different normal cell lines, namely, the mammary epithelium (HB2) and retinal pigment epithelium (hTERT-RPE-1) cell lines. The collected data demonstrated that the best catalyst performed the process at 30 °C with an irradiation time of 90 minutes, offering conversion and yield values higher than 80%. Interestingly, it could be used to process post-consumer samples, like a digital CD and a BPA-PC sheet, providing results comparable to the ones obtained using pristine BPA-PC and bisphenol A with good purity. Furthermore, the proposed protocol could be scaled up without a drop in performance.

Novel material design for sustainable development of agriculture is of key importance. In this regard, cocrystallization emerged as an effective laboratory synthesis as well as large-scale agricultural material production technique to enhance the efficiency of active ingredients by forming cocrystals with agriculturally compatible molecules and thereby improving their properties, such as moisture resistance, enzyme inhibition or nitrogen efficiency. This review provides a state of the art of this quickly developing area from the material design perspective and examines cocrystallized products for emerging applications in sustainable agriculture, such as novel fertilizer formulations that incorporate essential nutrients, as well as cocrystals for other applications, such as pest control. The chemical and crystal structures, bonding mechanisms, and the resulting properties of these cocrystals are discussed. Special attention is given to urea-based cocrystals. By integrating macro- (e.g., N, P, K, Ca, Mg and S) and micro-nutrients (e.g., Fe, Mn, Cu, Zn, B, Mo, Cl and Ni), these cocrystals provide novel nutrient delivery and management strategies. We then explore existing cocrystals that assist sustainable agriculture beyond nutrient delivery, e.g. herbicides, insecticides and fungicides. Finally, we discuss the potential routes to enhance agricultural cocrystal sustainability, such as novel methods of their synthesis, including mechanochemical processes.

5-Hydroxymethylfurfural (HMF), as a direct product of cellulose degradation, is an important biomass-based platform compound. The reductive amination of HMF is of significant industrial value among the upgrading reactions of HMF, which produces 5-hydroxymethylfurfurylamine (5-(aminomethyl)-2-furanmethanol, HMFA), an important intermediate of pharmaceutical and polymer materials. This work presents a facile one-pot synthesis of CuAu₃@CuPd nanocubes, which demonstrate exceptional activity and selectivity in the electrochemical co-reduction of HMF and NO₃⁻ to yield HMFA. Furthermore, an optimal faradaic efficiency of over 75% was achieved by etching the nanoalloy material with a moderate concentration of NOBF₄. The etching process exposed deeper CuPd active sites with a lattice distortion affected by the CuAu₃ core, thereby promoting the catalytic activity. Catalytic mechanism studies indicate that the C–N coupling reaction pathway involves the in situ generation and capture of the ^*NH₂OH intermediate. This work has paved a promising pathway for synthesizing high-value products from abundant biomass precursors utilizing the inorganic pollutant NO₃⁻ as a nitrogen source under ambient electrochemical conditions through the electrochemical co-reduction of HMF and NO₃⁻.

Vinyl chloride gas is a clear and non-irritating compound, often condensed into a liquid state for storage and transportation purposes. Its primary utilization revolves around the manufacturing of polyvinyl chloride (PVC), a material that constitutes around 12% of global plastic consumption. This study examines integrated production process routes for VC through simulation, optimization, and techno-economic analyses, combining the process routes of ethylene dichloride and vinylation in a single process route. The steady-state simulation is performed and analyzed statistically using fit regression while subjecting the simulation results to the linear model, quadratic model, and cubic model. Assessing the fitness of the model, the cubic model was found to give the best prediction and fitness of the simulation results owing to its R² value of 98.13%, compared to 98.02% and 75.19% of quadratic and linear models. Performing energy optimization (i.e., minimization) via the pinch analysis reveals that the process route performs excellently well in minimizing energy consumption with total energy savings of 6.916 × 106 W, resulting in 56.34% savings of the actual value of $112.58 million per year. A hypothetical vinyl chloride processing plant's net present value was also assessed, and a sensitivity analysis was conducted to demonstrate the impact of interest rate fluctuations. This demonstrates that an increase in interest rates led to a decrease in net present value. Using a total capital investment and annual production cost summed up to $2.331 millions and annual revenue of $ 0.651 million, resulting in a payback period and internal rate of return values of 3.58 years and 27.94%, respectively, compared with the 6 years and 27% reported in the literature. Therefore, this study's integrated approach and the techno-economic evaluation of the vinyl chloride production process route indicate a promising choice for a sustainable large-scale VCM production plant set-up.

Breaking the equilibrium limit is necessary to promote the production of diethyl carbonate (DEC) from CO₂ and alkoxysilanes. DEC yields are predicted to overcome the equilibrium limitation when substrates that generate oligomers as byproducts are used. In this study, we explored the catalytic synthesis of DEC using bis-/tris-triethoxysilane substrates over a Zr-based catalyst. Beyond-equilibrium DEC yields (>50% yield) are observed when typical substrates were used as the oligomer is obtained as a byproduct. For example, the isocyanate substrate solidified during DEC synthesis, yielding twice the amount of DEC generated from tetraethoxy orthosilicate. The isocyanate substrate was initially converted into an isocyanurate intermediate prior to polymerization to overcome the equilibrium limitation. The sustainability of this approach is highlighted by the feasibility of substrate regeneration from polymer byproducts. The demonstrated effectiveness of catalysis in promoting DEC from CO₂ can drive scientific and industrial advancements while maintaining sustainability.

The CO₂ reforming of methane effectively produces syngas using two prevalent greenhouse gases: CO₂ and CH₄. This study investigates the performance of three nickel-based catalysts, Ni/ZrO₂, Ni/CeO₂ and Ni/Ce_0.8Zr_0.2O_2−x, in the DRM reaction. Each catalyst was thoroughly examined using a range of techniques, including XRD, TPR, BET, TPD, HR-TEM, Raman, O₂-TPD, XPS, TGA and CO₂-TPD to assess its structural and catalytic properties. The Ni/Ce_0.8Zr_0.2O_2−x catalyst, combining the advantages of both supports to form a solid solution, achieved the best overall performance with enhanced activity and stability. Meanwhile, Ni/ZrO₂ and Ni/CeO₂ catalysts showed a tendency towards deactivation over extended reaction times. Characterization showed that incorporating zirconia into the CeO₂ lattice led to the solid solution synthesis with a solely defective cubic fluorite phase, as confirmed by XRD and Raman analysis. The TPR and CO₂-TPD revealed that the resulting Ni/Ce_0.8Zr_0.2O_2−x catalyst possesses strong metal–support interaction and higher CO₂ adsorption compared to pure CeO₂ and ZrO₂ samples. This composite support facilitated the generation of oxygen vacancies/active oxygen species, which are beneficial for reducing coke deposition. The Ni/Ce_0.8Zr_0.2O_2−x catalyst demonstrated exceptional performance, achieving around 90.8% methane conversion and 91.0% CO₂ conversion at 700 °C, with the resulting H₂/CO ratio precisely equal to one. The stability test revealed remarkable stability against coke deposition for Ni/Ce_0.8Zr_0.2O_2−x; meanwhile, Ni/ZrO₂ and Ni/CeO₂ are more susceptible to coke deposition, with the Ni/ZrO₂ sample showing a greater tendency towards graphitic coke deposition. This study highlights the importance of catalyst supports in optimizing the performance of nickel-based catalysts for CO₂ reforming applications.

In recent years, the imperative to minimise carbon dioxide (CO₂) emissions has become a central concern for both government and business organisations. To address this challenge, process integration tools such as pinch analysis have been widely applied for carbon management. However, existing tools do not consider CO₂ emissions, operating costs, and capital costs alongside optimal scheduling for decarbonisation strategies. To address this gap, this paper aims to present a methodology for screening cost-effective decarbonisation strategies and planning these strategies to achieve net-zero emissions in chemical process plants. The effectiveness of the methodology is demonstrated through two case studies on refinery and methanol processes. In the refinery case study, the average carbon intensity was 18.81 t CO₂ per k USD of operating cost, with a total CO₂ emission of 3722.97 t CO₂. Three main CO₂ emissions reduction strategies were deployed to achieve a 32% reduction in CO₂ emissions which include biomass combined heat and power, hydrogen recycling, and water electrolysis. In the methanol case study, the average carbon intensity was 0.72 t CO₂ per k USD, with a total CO₂ emission of 19 678 t CO₂ per day. To achieve a 49% reduction in emissions, strategies such as heat integration, compressor ratio adjustments, and recycle ratio adjustments were employed. The scheduling of these decarbonisation strategies was conducted to evaluate the respective economic feasibility of the payback period and loan required. The results indicate that implementing all strategies simultaneously results in the shortest payback period but incurs a high investment cost, leading to high financial risk. In order to lower the financial risk, the strategies are scheduled one by one by dispersing the investment costs.