Journal of CO2 Utilization最新文献

Valorisation of fruit processing by-products and waste is an important task for increasing the sustainability of agro-food sector. In this study, pitted sour cherry pomace was mechanically pre-fractionated into the 6 different particle size (>10, 4−10, 3−4, 1−3, 0.8−1, <0.8 mm) fractions (9.71−16.41 % proteins, 5.68−12.16 % fat, 62.55−78.39 % carbohydrates) and subjected to supercritical fluid extraction with CO₂ for the recovery of lipophilic constituents. Extract yield depended on fat content and was from 3.38 % to 8.69 %. Linoleic (38.52−47.11 %) and oleic (21.85−39.03 %) were major fatty acids, while triacylglycerols composed of these acids were major in the extracted oils. The concentrations of tocopherols, carotenoids and phytosterols in the extracts were 116.3−432.0, 1218−2564 and 4294−8449 μg/g. Antioxidant activity values were determined for the extracts and solids of initial dry pomace and its residue after extraction. Folin-Ciocalteu Index (basically similar to total phenolic content, TPC), ABTS^•+-scavenging and oxygen radical absorbance (ORAC) values of extracts were 7.86−8.75 mg of gallic acid equivalents/g, 1.72−6.37 and 35.12−95.49 of mg trolox equivalents/g, respectively. It is the first report on comprehensive characterisation of sour cherry pomace fractions extracted by supercritical CO₂.

A 3D flower-like structure composed of porous bismuth oxychloride (p-BiOCl) nanosheets was synthesized through a hydrothermal process utilizing Bi(NO₃)₃･5 H₂O, cetyltrimethylammonium bromide (CTAB) and LiCl. Powder X-ray diffraction (PXRD) studies confirmed the successful formation of the p-BiOCl. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were exploited to identify the nanosheet structure. The catalyst appeared as reduced Bi⁰ nanosheets at an applied cathodic potential of − 0.92 V (vs. RHE (reversible hydrogen electrode)). The maintenance of Bi nanosheet structures, controlled by the cationic surfactant of CTAB, resulted in enhanced electrochemical activity with a favorable Tafel slope and lower charge resistance. Defects of under-coordinated Bi sites and oxygen vacancy with interconnected 3D structures possess abundant active sites that further assist the activity. In 1.0 and 2.0 M KHCO₃ electrolytes, the catalyst achieved a maximum current density of − 80 and 100 mA/cm², respectively, at − 0.92 V (vs. RHE) with Faradaic efficiency > 99 % for converting CO₂ to formate in H-cell electrolyzers. The substantial H/D kinetic isotope effect revealed from H₂O versus D₂O electrolytes, and the feature of bicarbonate concentration-dependent performance provided the mechanistic insights that bicarbonate intermediates are in equilibrium with CO₂, activated by water, in the aqueous environment, together with the effects of electrode surface modulated by CTAB, are essential for the efficient electrochemical CO₂ reduction reaction to formate.

While the use of carbonated water in enhanced oil recovery (EOR) within the petroleum sector is well-documented, its applications in other fields remain relatively unexplored. This review aims to shed light on the versatile utility of carbonated water across various sectors, with the objective of stimulating further research to address sustainability challenges. Carbonated water can benefit industrial, agricultural, and domestic contexts by offering a sustainable method for utilizing waste CO₂. This review examines the diverse applications of carbonated water, including its role in enhancing oil recovery, aiding medical and healthcare research, reducing carbon footprint in construction, influencing biofuel production and green chemistry, and contributing to the agricultural sector, household, and cleaning domains. The findings suggest that carbonated water could serve as a viable source for CO₂ utilization, presenting significant advantages across various fields. Despite initial costs and infrastructure requirements, integrating carbonated water into existing practices - especially in agriculture and food production - offers clear benefits for offsetting carbon emissions. Continued research and development are essential to advance these technologies and promote sustainable and environmentally responsible practices. We assert that ongoing research and innovation are crucial to unlocking the full potential of carbonated water in various emerging applications.

Using carbon dioxide (CO₂) as a raw-material to produce value-added chemicals has a strategic role to play in the decarbonization of energy resources and the transition to a climate-neutral economy. E-methanol, Synthetic Natural Gas (SNG) and e-kerosene are one of the most promising pathways to convert CO₂. In this context, the aim of this work is to propose an optimized and integrated CO₂ to methanol process and then to compare it to the CO₂ to SNG process from economic and environmental points of views. An optimized reactor configuration in the CO₂ to methanol conversion unit has been successfully implemented in Aspen Plus® and leads to a thermal energy self-sufficiency of this unit. A heat integration with an advanced capture unit has been performed where 5 % of the heat requirement could be provided from the conversion unit while 95 % come from external steam source. Techno-economic assessment of the optimized process showed that methanol is more profitable when it is used as a raw material to synthetize other chemicals. As an energy carrier, SNG is more interesting. Compared to the reference scenario, a net CO₂ emission reduction of 70 % in the CO₂ to SNG route and of 60 % in the CO₂ to methanol route were obtained. Concerning the fossil depletion impact, in both cases, a reduction of more than 60 % was noticed (ca. 75 % in CO₂ to SNG route and 61 % in CO₂ to methanol case).

The global increase in energy demand requires a continuous search for renewable and clean alternative resources to fossil fuels. Hydrogen is emerging as a promising energy carrier for the future; its production via photocatalysis, driven by sunlight, can directly convert solar energy into a usable or storable energy resource. However, water splitting requires sacrificial agents or electron donors/hole scavengers, such as short-chain organic acids. This research explores the use of lactic acid as a source for photocatalytic hydrogen production, offering valuable alternatives for wastewater management and renewable energy production. This study employed the innovative supercritical antisolvent (SAS) technique to micronize the precursors of both the active phase (CeO₂) and co-catalyst (CuO), ensuring rapid and complete solvent removal and size reduction of photocatalyst precursors. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) analysis, Brunauer-Emmett-Teller (BET) analysis and thermogravimetric analysis (TGA). This study has shown that the micronization process resulted in a notable improvement in CeO₂ photocatalytic activity, attributed to the reduction of the dimensions of the powders. Hydrogen production was equal to 3989 μmol L⁻¹ for the SAS-produced photocatalyst while using a commercial CeO₂ sample resulted in H₂ production of 2519 μmol L⁻¹. The enhanced photoactivity of CeO₂-CuO composites was found to be related to the presence of CuO. The optimal CuO amount was equal to 0.5 wt%, determining a hydrogen production of 9313 μmol L⁻¹ after 4 h of UV irradiation time. A photocatalytic test carried out with deuterated water (D₂O) instead of distilled H₂O demonstrated that hydrogen was preferentially produced from water splitting reaction, whereas lactic acid acted as a sacrificial agent being oxidized from positive holes photogenerated in the valence band of CuO.

In this work, 25 % weight percentages of UiO-66 in TiO₂ nanoflower composite was treated with varying quantities of Tetraethylenepentamine (TEPA) to improve photoconversion of CO₂ into fuel using visible light (VL). The results revealed that maximum production rates of CH₄ and CH₃OH on TNF@25 %U-TEPA(2) sample were 64.59 and 2.47 µmol g_cat⁻¹ h⁻¹, respectively, at the optimum conditions of V-LP=150 W, P_CO2 =73 KPa, P_H2O =15 KPa and T=332.15 K. 15 LHHW models were evaluated based on different assumptions of rate determining step and the most abundant surface intermediate to obtain kinetics of the CO₂ photoconversion. The chosen model was the one that was closest to the experimental data. Furthermore, the kinetic rate and adsorption coefficients at T= 298.15–338.15 K and V-LP=150 W were obtained for the best-selected model. Finally, at T= 298.15–338.15 K, the activity energy of the produced CH₄ was determined as 3.6 kJ mol⁻¹.

Catalysis has optimized and improved production rates in many industrial processes. Conventional catalysis plays a key role in the mass-production of otherwise difficult to obtain substances. Plasma catalysis, plasma incorporation to appropriate catalysts, has been shown in literature to further outperform the typical conventional methods, and has shown potential to become a key production method in deep space exploration and survival. However, it faces a few more challenges that hinder it from being used industrially. In this review, we discuss known mechanisms in literature and the instrumentation and diagnostics that were utilized to be able to determine and explain these mechanisms in detail, and thus have led to the development of plasma catalysts with up to 80 % conversion rates for CO₂ conversion processes. We also discuss diagnostics that may be employed in the near future to reveal the last few unconventional mechanisms that must be explained in order to address the current instability and short life of catalysts due to the harsh conditions of plasma. In successful implementations of diagnostics in literature, they have proven to be the key to unlocking the knowledge required to develop appropriate catalysts optimized for converting CO₂ in a plasma environment.

Nowadays there is an urgent need for mitigating CO₂ emissions through clean energy and the development of new carbon capture and utilization (CCU) technologies. Among others, the use of bifunctional ionic liquids (ILs) addressed simultaneously CO₂ capture and conversion steps, having applied successfully to the propylene carbonate production case. In this work, a systematic evaluation of all representative cyclic carbonate literature was made, covering ethylene, propylene, butylene, hexylene, cyclohexene, and styrene cyclic carbonates, in order to guide the product role within the integrated CCU (ICCU) concept. The multiscale strategy combining molecular simulation (DFT -Density Functional Theory-, COSMO -COnductor-like Screening MOdel-), process simulation (COSMO/Aspen methodology), and life cycle assessment (LCA) was used to set up, simulate and evaluate the processes. ICCU configuration is the best approach when compared with sequential configuration for energy consumption analysis (reduction of 28, 28, 22, 11 and 6 %, respectively, for ethylene, propylene, butylene, hexylene, and cyclohexene cases) and CO₂ emissions associated (reduction of 38, 40, 31 and 14 %, respectively, for ethylene, propylene, butylene, and hexylene cases). The main variable of the results is the boiling point of the cyclic carbonate since heavy products impose technical limitations and even discard ICCU alternative. The ICCU concept works since all cyclic carbonates’ reaction enthalpies are higher than that of the IL-CO₂ one, which reduces heating requirements. Finally, energy demand can be slightly further reduced, partially recycling the cyclic carbonate to the capture unit.

Conversion of CO₂ into single-carbon (C1) or multi-carbon (C2+) compounds with high value-added chemicals is highly desirable but challenging. Under moderate, environmentally amiable conditions, photocatalysis may afford the deactivation and controllable C–C coupling of CO₂. Here, we prepared K₂Fe₂O₄/rGO, a photocatalyst containing magnetic ferrite, for CO₂ photocatalytic reduction. The optimized K₂Fe₂O₄/5 %rGO demonstrated the most efficient CO₂-to-methane conversion performance of 23.35 µmol g⁻¹ h⁻¹, which is 3.24 and 2.49 times the conversion rate constant of K₂Fe₂O₄ and rGO as photocatalytic catalysts, respectively. Therefore, the photocatalytic conversion of CO₂ to hydrocarbons [e.g., C_nH_2n+2, C_nH_2n, and C_nH_2n-2 (n = 1–5)] with K₂Fe₂O₄/rGO is an excellent method, with 100 % selectivity, for the production of multi-carbon hydrocarbons: 43 % CH₄ and 57 % C2+. The time-varying concentrations of hydrocarbon profiles for the photocatalytic reduction of CO₂ afford strong evidence for understanding the mechanisms underlying photoreduction. In an alkaline solution, K₂Fe₂O₄/rGO can mediate CO₂ photocatalytic reduction with simultaneous deoxygenation and C–C coupling.

Carbon-based materials have attracted significant attention in various catalytic applications. However, they are rarely reported for high-temperature catalytic reactions, owing to their limited thermal stability compared to other common materials such as silica and alumina, especially in oxidation reactions. CO₂ methanation became a pivotal research hotspot due to its ability to contribute to greenhouse gas mitigation. In addition, CO₂ methanation reactions can be carried out below 400 °C in a hydrogen atmosphere, which suits the thermal stability of many modified carbon materials. However, the number of reviews on CO₂ methanation does not match the huge number of the experimental publications on CO₂ methanation particularly reviews on carbon-supported catalysts. Motivated by the paucity of literature, including reviews on carbon-supported catalysts for CO₂ methanation, this review is focused on the catalytic performance of the carbon-supported catalysts of CO₂ methanation. It offers significant comparisons among all reported carbon-supported catalysts, providing a comprehensive study on the effect of the carbonaceous supports, such as graphene, biochar, and carbon nanotubes on the catalytic activity. In addition, it investigates the impact of promoters on the catalytic performance of the carbon-supported catalysts in CO₂ methanation and highlights the preparation methods and their optimized metal compositions that lead to the highest activity and selectivity. We conclude with a brief synopsis on the current challenges and perspectives on the future directions. This study paves the way for broader usage of carbon-supported catalysts for different thermal catalytic applications, not limited to CO₂ methanation.