Journal of CO2 Utilization最新文献

The majority of conventional flame retardants are made by chemical processes using petroleum resources, which cause serious pollution and waste of resources in the ecological environment. In this paper, flame retardants such as L-aspartic acid, DL-serine, L-tyrosine, L-lysine, L-phenylalanine, L-histidine, L-tryptophan, and glycine were employed to finish poly-(ethylene terephthalate) (PET) fabrics with supercritical CO₂ fluid. Scanning electron microscope (SEM) and Energy dispersive spectroscopy (EDS) were used to examine. the microstructure and chemical composition of flame-retardant PET fabrics. The limiting oxygen index (LOI) test and the vertical combustion test were used to assess the flame-retardant qualities of PET fabrics. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to test and assess the thermal properties of PET fabrics. The strength test was used to assess the mechanical properties of PET fabrics. The results showed that the amino acid flame retardants were successfully finished on the PET fabrics by supercritical CO₂ (SC-CO₂) technology and improved the thermal stability of the PET fabric. In comparison to untreated PET fabric, the elongation at break was 13–15 % greater, and the breaking strength was not reduced. Among them, the PET fabrics treated with L-aspartic acid and L-lysine had better flame-retardant performance, there were no droplets, the LOI values were greater than 30 %, and the char length was less than 10 cm. After 45 minutes of soaping and 3 times of washing, the LOI values were still above 28 %, and there were no droplets. Therefore, the PET fibers treated with amino acids using SC-CO₂ technology effectively improved the flame-retardant performance of PET fabrics.

This study proposed mixing HNO₃ solution with low-lime calcium silicate cement (CSC) to enhance the CO₂ capture and mechanical properties after CO₂-curing by increasing Ca²⁺ leaching at the initial stage. To clarify the influences of HNO₃ and the reaction mechanisms, various molar concentrations of HNO₃ (0, 0.01, 0.05, 0.1, 0.2, 0.5, and 1.0 M) were homogenized with CSC using a liquid-to-solid ratio (L/S) of 0.4 and CO₂-cured in a pressurized chamber for 24 h. The impact of HNO₃ on the initial reaction kinetics, Ca²⁺ leaching, phase composition after curing, CO₂ fixation capability, and mechanical performance were investigated. The findings revealed that the incorporation of HNO₃ had a pronounced influence on the degree of reaction, CO₂ fixation, and mechanical performance of CSC pastes. Nevertheless, the excessive incorporation of HNO₃ had a notable adverse impact on the reaction.

This study introduces a straightforward synthesis method for producing a hybrid material composed of halloysite and kojic acid, which catalyzes carbon dioxide (CO₂) conversion processes. Kojic acid, derived from malted rice fermentation, exhibits inherent chelating properties that facilitate the introduction of copper ions onto the material’s surface. Copper ions, an economically viable alternative to noble metals, catalyze CO₂ conversion reactions effectively. The hybrid catalyst was evaluated for two distinct CO₂ conversion pathways: photocatalytic methane production under simulated sunlight and CO₂ fixation into cyclic carbonates via epoxide reactions. The hybrid material demonstrates remarkable catalytic activity under mild conditions, achieving high conversion efficiencies at 45 °C for methane production and 70 °C for carbonate fixation at atmospheric pressure. Conversion of 31 % and 89 % were achieved for the photocatalytic CO₂ reduction and the carbonate fixation, respectively. FT-IR spectra confirmed the functionalization of the material. Additionally, its organic/inorganic hybrid nature is complemented by excellent thermal stability, as studied by TGA. It enables repeated utilization, maintaining a 25 % catalytic activity for methane production and 70 % for carbonate fixation after the fourth reuse. This research highlights the potential of using naturally derived materials for sustainable CO₂ mitigation.

Sector coupling plays a crucial role in reducing $C{O}_2$ emissions. The usage of renewable energies in Power-to-Liquid (PtL) processes is one option to link the energy, transport and chemical sectors. In addition to the sectors mentioned, other industries such as the cement industry need to be coupled for decarbonization. The BlueFire research project focuses on the investigation of an innovative process, plasma-based calcium looping. This process has the potential to serve as a fundamental component of a PtL plant by absorbing $C{O}_2$ from the environment and converting it into the syngas component carbon monoxide. It is furthermore an option for electrification of the important process of calcination in the cement industry. In this study, a techno-economic analysis is carried out to evaluate the potential of the plasma-based calcium looping. Integrated in a PtL plant to produce marine diesel, scenarios for the years 2020 and 2050 as well as different process schemes are defined in order to investigate the effects of different optimizations. In 2050, the integration of the plasma-based calcium looping is estimated to increase the PtL efficiency from 25 % to 32 %. This leads to net production costs ($\mathrm{NPC}$) of 2.5 EUR/L marine diesel. By illustrating the techno-economic potential, further development goals can be set to achieve $\mathrm{NPC}$ below 2.0 EUR/L. This can be achieved in the presented process setup with plasma efficiencies of 45 % at conversions of 65 %. The investigations allow statements regarding the system integration and the degree of optimization of the plasma-based calcium looping.

The use of synthetic natural gas (SNG) as a plug-and-play fuel coming from renewables can help to overcome the limitations given by the intermittency of renewable energy. A way to implement the production of SNG pass through the co-electrolysis of CO₂ to a mixture of hydrogen, carbon monoxide and carbon dioxide, steam and small amounts of methane, followed by CO and CO₂ methanation. The presence of different reactants and processes requires the comprehension and quantification of the kinetics of the reactions involved with the aim of optimizing methanation. In this work a kinetic model that considers both the direct CO₂ methanation and the indirect RWGS + CO methanation pathways has been developed over a Ni(10 %wt)/Ce_0.33Zr_0.63Pr_0.04O₂. The kinetic study made it possible to understand the influence of the reactants and products on the reactions through the calculation of reaction rates. This allowed to test, by linearization, the models found in the literature and their adjustment permitted to calculate sixteen kinetic parameters (activation energies, heats of adsorption and pre-exponential factors) present in the rate laws of methanation of CO₂, CO and the Reverse Water Gas Shift reaction. The models then made it possible to simulate the evolution of partial flow rates in an isothermal plug flow reactor and were compared to experimental data.

This study introduces a three-dimensional, densely packed amide polyphthalocyaninezinc, supported by fibrous phosphosilicate (FPS), for the first time (referred to as Complex@Zn-IL/FPS). The XPS and EDX images confirmed that the Complex@Zn-IL nanosaramic was evenly distributed on the FPS’s surface. The cycloaddition reaction from CO₂ and natural epoxide using Complex@Zn-IL/FPS nanosaramic as catalysts was reported. Furthermore, the catalyst’s structural heterogeneity was examined using various methods, including SEM, FT-IR, XPS, TEM, and TGA. There was no evidence of zinc leaching into the fluid. In addition, hot filtration provided a comprehensive understanding of the catalyst’s heterogeneous nature. The catalyst’s practical and straightforward reusability was noted after the reaction was completed.

Fracture toughness is a fundamental material property that quantifies the critical loading stress necessary to overcome the resistance to mechanical fracture propagation. Herein, exposure of minerals to certain fluids can cause alterations in the fracture toughness, for example, during underground CO₂ storage, influencing the integrity and sealing performance of the reservoirs. These changes would require an extensive examination of various properties of the layers, particularly those related to mechanical ones like fracture toughness. However, the role of water in changing the fracture toughness in different shale samples during the ScCO₂ interactions is still unknown. In this study, we collected three samples with different lithologies and compared the fracture toughness under three different states (before the interactions, under the interactions without water, and the interactions with water) to further quantify the role of water in the changes of the fracture toughness. The Mann-Whitney U test shows that the interactions with ScCO₂ could change the fracture toughness and the role of water involvement in the interactions could further change the fracture toughness. In addition, the role of water in the changes of the same sample parallel and perpendicular to the bedding lines is also different. In the directions parallel to the bedding, the fracture toughness of samples 2 (carbonate-rich felsic shale) and 3 (clayey carbonate-rich shale) increased by 39.2 % and 10.8 %, respectively. Conversely, the fracture toughness of sample 1 (clayey felsic shale) decreased by 21.3 %. In the directions perpendicular to the bedding, the fracture toughness of samples 1, 2 and 3 increased by 23 %, 55 %, and 8.58 %, respectively. Considering the samples that have been exposed to ScCO₂ with water, the fracture toughness of Sample 1 decreased by 5.8 %, while the fracture toughness of Sample 2 and Sample 3 increased by 65.8 % and 11.4 % respectively. This study shows that when considering the storage site for the CO₂, we should both consider the role of the lithologies and water in the interactions.

Aggregate accounts for 60‐80% volume fraction of concrete, which has a great influence on the CO₂ emission and performance of concrete. Apart from natural coarse aggregate (NCA), recycled coarse aggregate (RCA) and carbonation recycled coarse aggregate (CRCA) are becoming an important component. This study established a database containing 925 experimental samples of compressive strength (CS) and CO₂ emission, which including NCA, RCA, and CRCA concrete respectively. Additionally, the CO₂ intensity index was introduced to evaluate the CS and CO₂ emission. Machine learning (ML) methods were utilized to establish prediction models for CS, CO₂ emissions, and CO₂ intensity. The significance of features was analyzed through SHAP and PDP. For the optimization of coarse aggregate mix proportion, the GA and MOPSO algorithms were employed for single and bi-objective optimization designs, respectively. The results indicated that the optimization of coarse aggregate mix proportion can effectively reduce CO₂ emission and CO₂ intensity of concrete. A CRCA content of 30% is optimal for achieving both enhanced CS and reduced CO₂ emissions. The carbonation treatment of RCA presents a viable approach for mitigating CO₂ footprint and enhancing the mechanical properties of RCA concrete. The proposed optimization frame can facilitate appropriate decision making for low-carbon concrete design.

In the quest to mitigate excessive CO₂ emissions, the electrochemical reduction of CO₂ (eCO₂R) into multi-carbon fuels and vital chemical precursors emerges as a compelling strategy. Meticulous control of the C–C coupling on a catalyst surface is a grand challenge in the selective production of desired C₂₊ products. Ethane and propanol are among the most desirable C₂₊ products in the gas and liquid phase, respectively. Herein, we demonstrate facile femtosecond laser-enabled tuning of Cu selectivity towards ethane and propanol. The laser-enabled tailoring of the Cu surface induces a shift from C₁ products to ethane and propanol. This shift in product composition is attributed to the concurrent creation of hierarchical porous structures, the stabilization of {111}, {200}, and {220} Cu₂O facets, and the promotion of the Cu¹⁺ oxidation state. These alterations collectively enhance the adsorption strength, leading to an increased propensity for C-C coupling and, consequently, an elevated selectivity toward C₂₊ products.

The main objective of the present study is to synthesize iron oxide catalysts with engineered crystal defects and to clarify their crucial impact on the final catalytic activity in the CO2 hydrogenation process. The method used to engineer the desired crystal defects is based on changing the precipitation reaction conditions, such as the addition rate and the order of the precipitant during the primary phase of the synthesis of iron oxide catalysts. The catalyst synthesis process is based on the formation of iron oxalates in the first step, followed by thermal decomposition into iron oxides in the second step, which were subsequently tested as catalysts in CO₂ hydrogenation. The reversed double-beam photoacoustic spectroscopy used for advanced characterization of the prepared catalysts demonstrated that the observed change in catalytic activity is related to the energy and density of electron traps connected with the defects in the crystal lattice of the catalysts. These defects occur during the precipitation of oxalates, and their formation is significantly affected by changes in the precipitation conditions, i.e., the course of nucleation and growth of iron oxalate crystals. The results of the presented study thus affirmed the cardinal importance of defect engineering in heterogeneous catalysis.