Strategy For CO2 Capture Research Articles

Amine and fluorine co-functionalized MIL-101(Cr) synthesized via a mixed-ligand strategy for CO2 capture under humid conditions

The selective capture of CO2 in humid conditions on metal–organic frameworks is challenging due to competitive adsorption of H2O and CO2 on the active sites. Herein, amine and fluorine co-functionalized MIL-101(Cr) was synthesized and evaluated for use as CO2 adsorbent to overcome this issue. MIL-101(Cr)–NH2-F0.5 (CrA-F0.5) was prepared using a mixed-ligand strategy, and contains 2.9% nitrogen and 0.5% fluorine while maintaining the MIL-101(Cr) structure. Numerically, one 4F ligand per 20 amino ligands was included in the CrA-F0.5 structure. The calculated selectivity for CO2/N2 of CrA-F0.5 is 108 (CO2/N2 = 15/85) at 20 ℃ and 1 bar, and this value was 3.7 and 2.1 times higher than that of MIL-101(Cr) and MIL-101(Cr)–NH2, respectively. The results of CrA-F0.5 adsorption of CO2 indicated that amine and fluorine groups served as adsorptive sites for CO2 in this structure. The moderate isosteric heat of CO2 adsorption value (45 kJ mol−1) of CrA-F0.5 merits in desorption of CO2. The result of a hydrophobicity index test, indicated that CrA-F0.5 was 2.5 times hydrophobic than MIL-101(Cr)–NH2. In a CO2 and N2 breakthrough test, compared to the dry condition, the CO2 breakthrough time at 30 ℃ and 1 bar was reduced by 40% for MIL-101(Cr)–NH2 and by 10% for CrA-F0.5 in 60% relative humidity. The CO2 and N2 breakthrough results under humid conditions were consistent with the hydrophobicity index value, and the excellent water repellency of CrA-F0.5 was confirmed. CrA-F0.5 is considered a candidate suitable for CO2 adsorbent in an actual post-combustion CO2 adsorption process.

Boosting Energy Efficiency and Stability of Li-CO2 Batteries via Synergy between Ru Atom Clusters and Single-Atom Ru-N4 sites in the Electrocatalyst Cathode.

The Li-CO2 battery is a novel strategy for CO2 capture and energy-storage applications. However, the sluggish CO2 reduction and evolution reactions cause large overpotential and poor cycling performance. Herein, a new catalyst containing well-defined ruthenium (Ru) atomic clusters (RuAC ) and single-atom Ru-N4 (RuSA ) composite sites on carbon nanobox substrate (RuAC+SA @NCB) (NCB = nitrogen-doped carbon nanobox) is fabricated by utilizing the different complexation effects between the Ru cation and the amine group (NH2 ) on carbon quantum dots or nitrogen moieties on NCB. Systematic experimental and theoretical investigations demonstrate the vital role of electronic synergy between RuAC and Ru-N4 in improving the electrocatalytic activity toward the CO2 evolution reaction (CO2 ER) and CO2 reduction reaction (CO2 RR). The electronic properties of the Ru-N4 sites are essentially modulated by the adjacent RuAC species, which optimizes the interactions with key reaction intermediates thereby reducing the energy barriers in the rate-determining steps of the CO2 RR and CO2 ER. Remarkably, the RuAC+SA @NCB-based cell displays unprecedented overpotentials as low as 1.65and 1.86V at ultrahigh rates of 1and 2Ag-1 , and twofold cycling lifespan than the baselines. The findings provide a novel strategy to construct catalysts with composite active sites comprising multiple atom assemblies for high-performance metal-CO2 batteries.

Three-dimensional simulation of a gas-fueled chemical looping combustion system with dual circulating fluidized bed reactors

Chemical looping combustion (CLC) is a concept with inherent separation of CO2 and is the key strategy for CO2 capture at current stage. In this work, three-dimensional simulations of chemical looping combustion system using gaseous fuel are carried out for obtaining the flow behavior and reaction characteristics. The model is developed in the frame of Eulerian approach. The configuration with dual circulating fluidized bed reactors is built according to the experimental structure with designed power 120 kW. The oxygen carrier, a nickel based oxide, circulates between the reactors to transport the oxygen and heat. The time-averaged and local flow behaviour and reaction characteristic are analysed. The pressure, solid mass distribution and gaseous products are predicted numerically and compared with experimental measurement for the validation. The influences of operating temperature, solid inventory and fuel power on the performance of system are discussed. Results turn out that the numerical models developed in this work can be used for the design or scale-up of CLC system. The entrained solid circulating rate fluctuates around a constant value. The highest conversion rate of CH4 is 87.4% for reference case and it decreases with increasing the fuel power. With large amount of mass inventory is beneficial for getting high conversion rate of methane. The conversion rate reaching 0.978 when increasing the operating temperature to 1380 K. The largest reduction level of oxygen carrier is 0.29 for current work which is detected at the bottom of fuel reactor.

Amine and Fluorine Co-Functionalized Mil-101(Cr) Synthesized Via a Mixed-Ligand Strategy for Co2 Capture Under Humid Conditions

Amine and Fluorine Co-Functionalized Mil-101(Cr) Synthesized Via a Mixed-Ligand Strategy for Co2 Capture Under Humid Conditions

Selective CO2 capture and multiresponsive luminescent sensor in aqueous solutions of cadmium metal-organic framework based on trigonal rigid ligand

We report here a new fashioned cd-metal-organic framework (MOF) exhibiting a (5, 6)-connected 2-nodal net, [Cd3(LMe)(H2O)]·DMF·3H2O constituted by two different metal clusters and a trigonal rigid 6-connected ligand. The analytic reveal that complex is a 3D structure. Each (LMe)6− ligand is linked to five dinuclear SBUs, which forms a 2D lay, and Cd1 ions are linked by two different deprotonated carboxylates to construct a 3D porous framework. IAST manifested that the selectivity coefficients under 1 bar for the N2/CO2 (85: 15) and CH4/CO2 (50: 50) compounds were 86 and 6 at 273 K, respectively. Complex exhibited selectivity of CO2 relative to N2 and CH4 upon removal of solvates. Moreover, the complex caused emission quenching in the existence of Fe3+, MnO4− and CHCl3 organic solvent molecules. The multi-response fluorescence probe has lofty sensitivity and low limit of detection in the existence of Fe3+ and MnO4−. It thus appears that the Cd-MOF is not only a useful strategy for CO2 capture, but a fluorescent transducer for simultaneous exploration of organic solvent, metal ions and inorganic anions.

Amino-functionalized magnetic nanoparticles for CO2 capture

ABSTRACT CO2 accumulation is inducing an effect of global warming. Adsorption using solid sorbents is proving as an effective strategy for CO2 capture and reuse. The aim of this study was to develop amino-functionalized magnetic nanoparticles by depositing various amines through co-precipitation or impregnation-sonication. Structural characteristics were studied through SEM, BET and XRD analyses, evidencing coarse particles with low crystallinity and surface areas of 100–150 m2 g−1, while FT-IR confirmed CO2 interacting with substrate. The load of functional group, particles stability, and CO2 sorption capacity were assessed through elemental and thermogravimetric analysis. It was found that loads of functional groups ranging from 1.6 to 6.1 wt.%. were deposited, and most samples showed sound stability up to 100°C. Sorption capacities were in the range 0.2–1.5 g gNH2 −1, the highest being 1.46 g gNH2 −1 for ɛ-aminocaproic acid. Such sample also exhibited good recyclability, with a performance drop of 11% after many cycles. CO2 uptake decreased with increasing temperature in the range 25–45°C, suggesting a chemical bond between CO2 and amines. Amino functionalized particles could thus be an interesting solution for CO2 capture and utilization thanks to fast kinetics, recyclability, and ease of separation.

Continuous Flow Solar Desorption of CO2 from Aqueous Amines

Recovery of captured carbon dioxide (CO2) is considered the most energy-intensive stage of postcombustion CO2 capture strategies by aqueous amines. In response, an optically transparent flow reactor with continuous in operando CO2 collection using light-absorbing, graphite-titania composite microparticles is developed for the energy-efficient solar desorption of CO2 from saturated aqueous amine absorbents. The synthesized graphite-titania composite microparticles are demonstrated to be a more effective packing material for continuous CO2 solar desorption in the packed-bed flow reactor compared to other candidates, including titania and carbon black. The effect of continuous and discrete parameters, including irradiance, residence time, amine concentration, and amine chemical structure on the efficiency of solar-enabled CO2 desorption using the developed continuous flow strategy with the graphite-titania composite microparticle packing is studied in detail. Furthermore, the potential for the implementation of a control strategy by adjusting the aqueous amine stream flow rate to achieve constant CO2 desorption efficiency with dynamic solar irradiance is discussed. Finally, the continuous CO2 desorption stability over an extended period of time (12 h) is examined with an average single-pass efficiency of 64%.

Construction of hexanuclear Ce(III) metal−porphyrin frameworks through linker induce strategy for CO2 capture and conversion

In this article, we report a series of hexanuclear rare-earth MOFs based on Ce (III) and 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, namely Ce-PCN-224, with a new zln topology through linker induce strategy. Ce-PCN-224 exhibits permanent porosity, high water and thermal stabilities, and the ability to adsorb dye molecules in the aqueous environment. Moreover, after post-metallation with Fe, Co, and Ni, Ce-PCN-224(Fe) and Ce-PCN-224(Co) were proved to be efficient heterogeneous catalysts for the cycloaddition of CO2 with epoxides, attributed to the combination of multiple Lewis acidic sites.

One-step multiple-site integration strategy for CO2 capture and conversion into cyclic carbonates under atmospheric and cocatalyst/metal/solvent-free conditions

The capture of CO2 and subsequent conversion into high value-added chemicals under atmospheric conditions is an on-going challenge. This work reports a facile multiple-site integration strategy for the capture of low-concentration CO2 and subsequent cocatalyst/metal/solvent-free coupling with epoxides to synthesize cyclic carbonates under atmospheric conditions. Through the one-step integration of commonly-used imidazolium ionic liquids (ILs) and quaternary ammonium salt, porous polyILs with acidic/basic moieties (–NH2, –COOH), active cations (imidazolium, quaternary ammonium) and nucleophilic counterions (Br–, Cl–, OH–) have been fabricated. The cooperation of nucleophilicity, basicity and acidity, which is critical for the activation of CO2 and epoxides, has been flexibly modulated via regulating the type and content of the multiple-sites. The polyILs show good low-concentration CO2 affinity, high catalytic activity under atmospheric conditions, efficient recyclability and excellent tolerance for a variety of epoxides, and the new strategy developed shows great potential for practical applications in low-energy fixation of CO2.

A comprehensive review on high-temperature fuel cells with carbon capture

High-temperature fuel cells and their hybrid systems represent one of the most promising technologies with high conversion efficiency. The configuration of such kind of system could facilitate an easy capture of CO2. Several novel CO2 capture strategies have been developed based on high-temperature fuel cells, such as solid oxide fuel cell (SOFC), molten carbonate fuel cell (MCFC) and direct carbon fuel cell (DCFC). However, related review which focus on their system integration and performance evaluation is still rare. The aim of this study is to improve interest in high-temperature fuel cell with CO2 capture by providing an overview of the status of such kind of cutting-edge technologies. To approach this goal, the major strategies and technologies for fuel cells and their hybrid system with CO2 capture have been reviewed. Simultaneously, the characteristics of fuel cell technologies are summarized and the technical and economic performance of the fuel cell with CO2 capture are explored and discussed as well. The existing challenges that required to be overcome in fuel cell with CO2 capture technology are highlighted with aspects on fuel cell module scale-up, cost, safety, reliability and capture energy, etc. Finally, opportunities for the future development of high-temperature fuel cell with CO2 capture technologies are discussed. The conclusion remarks of this investigation indicate that fuel cell integrating CO2 capture process is a promising route to sustainable future, and could even be more effective if fuel cell technology can be commercialized.

Li–CO2 and Na–CO2 Batteries: Toward Greener and Sustainable Electrical Energy Storage

Metal-CO2 batteries, especially Li-CO2 and Na-CO2 batteries, offer a novel and attractive strategy for CO2 capture as well as energy conversion and storage with high specific energy densities. However, some scientific issues and challenges existing restrict their practical applications. Here, recent progress of crucial reaction mechanisms on cathodes in Li-CO2 and Na-CO2 batteries are summarized. The detailed reaction pathways can be modified by operation conditions, electrolyte compositions, and catalysts. Besides, specific discussions from aspects of catalyst design, stability of electrolytes, and anode protection are presented. Perspectives of several innovative directions are also put forward. This review provides an intensive understanding of Li-CO2 and Na-CO2 batteries and gives a useful guideline for the practical development of metal-CO2 batteries and even metal-air batteries.

Modeling and environmental evaluation of a system linking a fishmeal facility with a microalgae plant within a circular economy context

Microalgae cultivation has been proposed as a strategy to capture CO2 from industries. Besides that, feeding microalgae cultures with flue gas could improve their growth and environmental performance. Nevertheless, the potential of microalgae cultivation as a CO2 capture strategy should be contrasted against real volumes of emissions from industries. In view of this fact, we modeled an integrated system in which microalgae capture CO2 from flue gas of a fishmeal and fish oil facility. A cogeneration turbine system provides heat and electricity for fishmeal production and microalgae cultivation. Further requirements of electricity are fulfilled from the grid, considering different mixes. We constructed a baseline scenario and six alternative scenarios, where the capacity of microalgae plant matches the amount of CO2 released by the cogeneration system. Moreover, we assumed that microalgae biomass could partially replace fishmeal, which allows attaining an additional reduction of emissions. We carried out a carbon balance with and without a life cycle approach to evaluate the environmental performance of the proposed system. Results showed that the integrated system released less CO2 compared to the traditional one during the operation phase. However, from a life cycle perspective, environmental benefits were only achieved when low carbon electricity was consumed. Otherwise, the integrated system entailed harmful burdens to the environment. Moreover, considering the maximum achievable absorption of CO2 (8.92% reduction of greenhouse gas emission), it would require 3.16 ha to cultivate microalgae. These results highlight the importance of including land-use among the life cycle impacts categories when microalgae system are proposed for providing environmental services, such as CO2 capture.

Modelling of Enzymatic Reactive CO 2 Absorption

Post-combustion CO2 capture strategy asks for novel effective processes avoiding the use of polluting solvents and oriented towards CO2 utilization. Recent research efforts are focused on the development of CO2 absorption processes promoted by the activity of the enzyme carbonic anhydrase (EC - 4.2.1.1) (Leimbrik et al., 2017; Russo et al., 2013). This ubiquitous enzyme is able to catalyse the CO2 hydration reaction and can be used to enhance CO2 absorption rate into aqueous alkaline solvents such as carbonate solutions. The adoption of the biomimetic strategy for post-combustion CO2 capture is based on the use of environmental friendly solvents. Recent studies on the development of carbonic anhydrase biocatalysts for CO2 capture through enzymatic reactive absorption focused on different enzyme immobilization techniques. Moreover, theoretical studies showed the potential use of immobilized enzymes in typical gas-liquid contactors. The present contribution concerns the rational design of absorption columns through the use of kinetic parameters assessed for carbonic anhydrase immobilized on fine particles. The kinetics of CA immobilized on magnetic nanoparticles have been previously characterized under conditions relevant for the industrial application (K2CO3 solutions at 25-40°C and at different carbonate conversion degrees) (Peirce et al., 2017; Peirce, 2017). The model simulations provided information on the performances of the technical grade CA and of the biocatalyst made with nanoparticles (NPs) coated with covalently immobilized CA. The results showed that effective intensification of the capture process can be achieved using the fine slurry biocatalyst.

PEST study of CO2 capture strategy from 2007 to 2018

PEST study of CO2 capture strategy from 2007 to 2018

Charge-modulated CO2 capture

Recently, the concept of using charge-modulation to manipulate the interaction of adsorbate molecules such as CO2 on certain sorbent materials has been advanced through a series of first principle computational predictions. The interactions switched on through charge-modulation shifting the Fermi level are in part, but by no means exclusively, electrostatic. In addition to electrostatics, the Fermi level shifting can be viewed as a way to modulate not only the position but also the identity and character of the frontier orbitals on the sorbent materials that engage with the adsorbate molecules. Thus, a rich new space for electrochemical modulation of surface-molecular interactions—guided by first principle computational modeling—suggests itself. Here we summarize the growing computational literature on switchable CO2 capture strategies. We also provide some new insights into contrasting electrostatic versus chemical responses to charge-modulation as exemplified by water versus CO2 on N-doped graphene surfaces, which suggest that this CO2 capture strategy could be water tolerant.

Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

Ideal carbon dioxide (CO2) capture materials for practical applications should bind CO2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO2 capture has been proposed to be a controllable, highly selective, and reversible CO2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO2 capture. Our results reveal that the binding strength of CO2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged borophene achieves CO2 capture capacities up to 6.73 × 1014 cm-2. In contrast to the other CO2 capture methods, the CO2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO2 from mixtures with CH4, H2, and/or N2. This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

High and Selective Carbon Dioxide Capture in Nitrogen-Containing Aerogels via Synergistic Effects of Electrostatic In-Plane and Dispersive π-π-Stacking Interactions.

A new strategy for CO2 capture is reported based on the synergistic effect of electrostatic in-plane and dispersive π-π-stacking interactions of amide and indole with CO2. Density functional theory illustrated that the amide group can have an increased ability to capture CO2 molecules that were just desorbed from an adjacent indole unit. We used this strategy to fabricate a microporous aerogel that exhibited a superior CO2 capture performance in both dry and wet conditions. The proposed synergistic effect is expected to be a new rationale for the design of CO2 capture materials.

Synthesis of mesoporous carbon nanospheres via “pyrolysis-deposition” strategy for CO2 capture

Exhaust gas is always pyrolysed from soft template and carbon precursor in the carbonization process to synthesize mesoporous carbon, resulting in environmental pollution and waste of energy. In this work, we describe a new method, referred to as a “pyrolysis-deposition” strategy, for synthesis of mesoporous carbon nanospheres (MCNs) by using the exhaust gas pyrolysed from resin polymer as carbon precursor. The synthesis process is simply accomplished in one tube furnace, in which the exhaust gas is pyrolysed from resin polymer and synchronously deposits on Fe-containing hollow mesoporous silica nanospheres (Fe@HMSNs) and converts to carbon under the catalysis of Fe. Highly dispersible MCNs with spherical morphology are obtained after removing Fe catalyst and etching silica. Some walnut-like carbon spheres with core–shell structure are also formed. The exhaust gas is fully utilized by converting to carbon and less exhaust gas emits into the air, which is advantageous to save energy and protect the environment. The resultant MCNs exhibit high specific surface area (1240 m2 g−1), uniform mesoporous size (4.1 nm) and high performance for CO2 capture with a capacity of 2.36 and 4.76 mmol g−1 at 1.0 bar under 25 and 0 °C, respectively.

The Holy Grail: Chemistry Enabling an Economically Viable CO2 Capture, Utilization, and Storage Strategy.

Technologies for reducing the concentration of CO2 in our atmosphere are essential for mitigating the risks of climate change, and novel chemistry is required for such technologies to work at scale. Here, we highlight challenges that chemists must overcome to realize the Holy Grail of an economically viable strategy for CO2 capture, utilization, and storage.

Numerical modeling of co-injection of N2 and O2 with CO2 into aquifers at the Tongliao CCS site

Co-injection of impurities such as N2 and O2 with CO2 into aquifers is considered as an economical strategy for CO2 capture and storage (CCS). Compared to pure CO2 injection, impurities contained in CO2 stream will affect geophysical and geochemical properties of the systems and further affect flow and reactive transport processes. This study establishes a mutual solubility model for CO2–N2–O2-brine systems with pressure up to 600bar, temperature up to 100°C and salinity up to 6mol/kg water by using the fugacity-activity method for the phase equilibrium. The model is then incorporated into TOUGH2/EOS7C and TOUGHREACT, forming a new improved module we call EOS7Cm. EOS7Cm is applied to simulate the reactive transport process of co-injection of air with CO2 into a shallow aquifer at the Tongliao field experiment using a 2-D radial homogeneous and anisotropic model. The fast reactive calcite and dolomite are considered as the only reactive mineral in the model. The results fit with the flow and reactive phenomenon observed at the site. It is shown that chromatographic partitioning processes of impurities occur in both gas and aqueous phases due to the difference in the solubility between CO2 and impurities. The front of gaseous O2 slightly lags behind that of gaseous N2, while gaseous CO2 lags behind gaseous O2. The distributions of the dissolved gases in the aqueous phase are similar to that in the gas phase. After the CO2 breakthrough the pH drops rapidly to about 5.0, which pronounces the dissolution of carbonate minerals. The ratio of N2 and O2 does not significantly impact the distribution pattern of gas species, but it affects the transport distance of the gases and the percentage of gas species at the gas front.