CO2 Elimination Research Articles

A multimodal characterization of cardiopulmonary resuscitation-associated lung edema

BackgroundCardiopulmonary resuscitation-associated lung edema (CRALE) is a phenomenon that has been recently reported in both experimental and out-of-hospital cardiac arrest patients.We aimed to explore the respiratory and cardiovascular pathophysiology of CRALE in an experimental model of cardiac arrest undergoing prolonged manual and mechanical chest compression (CC). Oxygen delivery achieved during mechanical or manual CC were also investigated as a secondary aim, to describe CRALE evolution under different hemodynamic supports generated during CPR.MethodsVentricular fibrillation (VF) was induced and left untreated for 5 min prior to begin cardiopulmonary resuscitation (CPR), including CC, ventilation with oxygen, epinephrine administration and defibrillation. Continuous mechanical and manual CC was performed alternating one of the two strategies every 5 min for a total of 25 min. Unsynchronized mechanical ventilation was resumed simultaneously to CC. A lung computed tomography (CT) was performed at baseline and 1 h after return of spontaneous circulation (ROSC) in surviving animals. Partitioned respiratory mechanics, gas exchange, hemodynamics, and oxygen delivery were evaluated during the experimental study at different timepoints. Lung histopathology was performed.ResultsAfter 25 min of CPR, a marked decrease of the respiratory system compliance with reduced oxygenation and CO2 elimination were observed in all animals. The worsening of the respiratory system compliance was driven by a significant decrease in lung compliance. The presence of CRALE was confirmed by an increased lung weight and a reduced lung aeration at the lung CT, together with a high lung wet-to-dry ratio and reduced airspace at histology. The average change in esophageal pressure during the 25-min CPR highly correlated with the severity of CRALE, i.e., lung weight increase.ConclusionsIn this porcine model of cardiac arrest followed by a 25-min interval of CPR with mechanical and manual CC, CRALE was consistently present and was characterized by lung inhomogeneity with alveolar tissue and hemorrhage replacing alveolar airspace. Despite mechanical CPR is associated with a more severe CRALE, the higher cardiac output generated by the mechanical compression ultimately accounted for a greater oxygen delivery. Whether specific ventilation strategies might prevent CRALE while preserving hemodynamics remains to be proved.

Effect of introducing oxygen into ethylene tar pitches on their carbonaceous products

Ethylene tar is a prospective precursor for preparing carbonaceous materials, which is regard-ed as a representative soft carbon material after carbonization. However, the introduction of oxygen can influence the morphology of the final carbonaceous materials. For the introduction of oxygen, dealkylation and dehydrogenation will be promoted and the molecules can be linked more effectively. For the subsequent carbonization, the biphenyl structures caused by the deoxygenation via the elimination of CO2, as well as the reserved aromatic ether bonds, can facilitate the strong cross-linking, which will restrain the movement of the carbon layers and the formation of the graphitic structures. After the graphitization treatment at 2800 oC, the oxidized pitch can lead to short-range ordered and long-range unordered structures, while the sample without oxidation can result in long-range ordered graphitic structures. It can be proved that a simple oxidation-carbonization treatment can transform ethylene tar into hard carbon structures.

Eco-environmental regret-aware optimization of networked multi-energy microgrids with fully carbon elimination and electric vehicles' promotion

With the escalating concern of global warming propelled by the rise in Earth's temperature, the need for effective CO2 management has become crucial. This paper presents an innovative CO2 elimination approach, wherein a multiple integrated system of energies (MISEs) incorporating sustainable resources, including renewable resources (RENs), plug-in electric vehicles (PEVs), and demand response programs, is optimized. The proposed carbon elimination framework begins by modeling the onsite carbon capturing and recycling within each MISE. To effectively utilize the onsite carbon recycling facilities and achieve carbon neutrality, the proposed model also incorporates carbon transfer capability between MISEs, thereby enhancing the efficiency of overall carbon recycling. Furthermore, a stochastic p-robust optimization technique is proposed to effectively manage uncertainties by combining the advantages of stochastic programming and robust optimization. This uncertainty modeling approach promotes greater utilization of sustainable resources like PEVs and RENs due to their lower operational regrets from economic and environmental perspectives. Based on the simulation results, implementing the p-robust-based regret assessment technique led to the total operation cost increasing by only 2.75 %, while achieving a significant 44.5 % reduction in maximum relative regret. These results underscore the effectiveness of the proposed framework in enhancing both the economic and environmental performance of MISEs.

Interfacial Robustness and Improved Kinetics of Single-Crystal Ni-Rich Co-Free Cathodes Enabled by Surface Crystal-Facet Modulation.

The elimination of Co from Ni-rich layered cathodes is critical to reduce the production cost and increase the energy density for sustainable development. Herein, a delicate strategy of crystal-facet modulation is designed and explored, which is achieved by simultaneous Al/W-doping into the precursors, while the surface role of the crystal-facet is intensively revealed. Unlike traditional studies on crystal structure growth along a certain direction, this work modulates the crystal-facet at the nanoscale based on the effect of W-doping dynamic migration with surface energy, successfully constructing the core-shell (003)/(104) facet surface. Compared to the (003) plane, the induced (104) facet at the surface can provide more space for Li+-activity, enabling lower interfacial polarization and higher Li+-transport rate. Additionally, bulk Al-doping is beneficial for enhancing the Li+-diffusion from the exterior surface to the interior lattice. With improved interfacial stability and restrained surface erosion, the product exhibits superior capacity retention and boosted rate performance under the elevated temperature.

Probing the Reaction of Propargyl Radical with Molecular Oxygen by Synchrotron VUV Photoionization Mass Spectrometry.

Self-reaction of propargyl (C3H3) radical is the main pathway to benzene, the formation of which is the rate-controlling step toward the formation of polycyclic aromatic hydrocarbons (PAHs) and soot. Oxidation of C3H3 is a promising strategy to inhibit the formation of hazardous PAHs and soot. In the present study, we studied the C3H3 + O2 reaction from 650 to 1100 K in a laminar flow reactor and identified the intermediates and products by synchrotron VUV photoionization mass spectrometry. 2-Propynal, ethenone, formaldehyde, CO, CO2, C2H2, C2H4, and C3O2 were identified. Among them, 2-propynal, ethenone, and formaldehyde provided direct evidence for the branching reaction of C3H3 + O2 → HCCCHO + OH, C3H3 + O2 → H2CCO + CHO, and C3H3 + O2 → H2CO + CHCO, respectively. Potential energy surface calculation and mechanistic analysis of the C3O2 formations implied that C3H3 + O2 → CCCHO + H2O and C3H3 + O2 → HCCCO + H2O could occur, despite lacking direct observations of CCCHO and HCCCO radicals. The formation of ethenone and CO suggested the occurrence of the two CO elimination channels. We incorporated these validated reactions and the corresponding rate coefficients in the kinetic model of NUIGMech1.3, and the simulation showed obvious improvements toward the measured mole fractions of C3H3 and H2CCO, suggesting that the new C3H3 + O2 reaction channels were crucial in the overall combustion modeling of the important intermediate propyne (C3H4).

Efficient Elimination of Co (II) Ions from Watery Solutions Utilizing Eco‐Friendly, Inexpensive, Natural, and Modified Potato Peels

AbstractThis study is concerned with the physicochemical investigation of cobalt (II) sorptions from aqueous solution by potato peel (PP) and NaOH/CaCl2/C2H5OH‐modified potato peel (MPP). The sorption conditions of PP and MPP under optimized conditions were optimized according to the maximum effects of the main factors affecting the sorption processes (PP and MPP dosage, sorbate concentration, interaction time, and temperature) at pH 6.78. The kinetic and equilibrium experimental sorption data of the studied sorbates were simulated using commonly used models and were found to fit well with pseudo‐second‐order and Langmuir models. The Co(II) ion adsorption capacity of PP was determined as 12.25, 16.44, and 20.74 mg/g, respectively, at various temperatures (25, 35, and 45 °C), while the adsorption capacity of MPP under the same conditions was determined as 41.49, 52.35, and 62.50 mg/g. Thermodynamic parameters determined for each sorption system showed that the sorption processes were endothermic and spontaneous. The results of this study emphasize that both PP and MPP can be used as effective sorbents for removing pollutants from water.

Multisite Amino‐Allylidene Ligands from Thermal CO Elimination in Diiron Complexes and Catalytic Activity in Hydroboration Reactions

AbstractThe new diiron(I) complexes [Fe2Cp2(μ‐CO){μ‐k3C,kN‐C(R1)C(R2)C(CN)NMe(R)}], 3 a–o (R=alkyl or 4‐C6H4OMe; R1=alkyl, aryl, ferrocenyl (Fc), thiophenyl, CO2Me or SiMe3; R2=H, Me or CO2Me) were synthesized in moderate to high yields from the thermal decarbonylation of the bis‐carbonyl precursors 2 a–o, and were structurally characterized by IR and NMR spectroscopy, and single crystal X‐ray diffraction in four cases. Electrochemical behavior of one complex was also investigated. Complexes 3 a–o comprise a highly functionalized, multisite amino‐(cyano)allylidene ligand, including metal coordination of a tertiary amine group. Selected complexes displayed negligible to moderate catalytic activity in CO2/propylene oxide coupling, working under ambient conditions. Additionally, they were investigated as catalysts for the conversion of benzaldehyde to the corresponding borate ester 6 a, using pinacolborane (HBpin) as the borylating agent. Most complexes achieved good conversions at room temperature with 1 % catalyst loading, and data highlight the significant influence of the multisite ligand substituents on the catalytic performance. Notably, complex 3 m (featuring R=4‐methoxyphenyl, R1=Fc, R2=H) displayed the highest activity and effectively catalyzed the hydroboration of various aldehydes and ketones. A plausible mechanistic cycle involves metal coordination of the carbonyl substrate, its activation being possibly facilitated by intramolecular interactions.

Highly efficient Rh-doped MnO2 nanocatalysts for complete elimination of CO at room temperature.

Obliteration of carbon monoxide is significant due to its hazardous effect on human health and potential application in different fields. Catalytic CO oxidation at lower temperature is the most convenient method to diminish the toxicity of CO. The low-cost catalysts which are exhibiting higher activity at lower temperature with good stability are in demand. The nanosized Rh-doped MnO2 catalysts have been prepared by dextrose-assisted co-precipitation method. Catalytic CO oxidation reaction was carried out over these prepared nanocatalysts under environmentally suitable conditions. XRD confirms the phase formation of prepared catalysts. These samples exhibit rod-like morphology with thickness of rods of less than 10nm which is substantiated from electron microscopy images. XPS data reveals the oxidation state of Mn (+ 4) and Rh (+ 3). These catalysts are highly active for CO oxidation reaction at lower temperature, and one showed complete CO conversion at room temperature. The time-on-stream studies revealed that these catalysts are highly stable for CO oxidation for several hours. These catalysts are decidedly stable in moist condition and also showed higher activity in the presence of moisture, indicating participation of moisture in the oxidation reaction at above room temperatures.

Role of Atomicity and Interface on InOx-TiO2 Composites: Thermo-Photo Valorization of CO2.

The synthesis, physicochemical, and functional properties of composite solids resulting from the surface spread of oxidized indium species onto nanoplatelets of anatase were investigated. Both the size and the interaction between the indium- and titanium-containing components control the functional properties. In the reduction of CO2 to CO, the best samples have an indium content between ca. 2 and 5 mol % and showed an excess rate over the photo and thermo-alone processes above 33% and an energy efficiency of 1.3%. Subnanometric (monomeric and dimeric) indium species present relatively weak thermal catalytic response but strong thermo-photo promotion of the activity. A gradual change in functional properties was observed with the growth of the indium content of the solids, leading to a progressive increase of thermal activity but lower thermo-photo promotion. The study provides a well-defined structure-activity relationship rationalizing the dual thermo-photo properties of the catalysts and establishes a guide for the development of highly active and stable composite solids for the elimination and valorization of CO2.

Cobalt(VI)-oxo species-mediated selective oxidation of electron-rich organic contaminants by Co-loaded hydroxylated g-C3N4 with high resistance to an inhibitory effect of background constituents

Understanding of the selectivity of high-valent cobalt-oxo species (Co(IV)O) toward diverse organic pollutants with different characteristics in the presence of background constituents remains limited. Here, we prepared Co-loaded hydroxyl group-grafted graphitic carbon nitride (Co-OHCN) using a facile method for the effective formation of Co(IV)O. The role of the hydroxyl group in anchoring Co ions was investigated using several characterization methods (TEM, XRD, FT-IR, and XPS). Co-OHCN exhibited superior efficiency in degrading 4-chlorophenol (4-CP) (98.0 % ± 0.3 %) within 15 min of peroxymonosulfate (PMS) activation reaction. In the Co-OHCN/PMS system, Co(IV)O had the highest steady-state concentration ([Co(IV)O] = 1.40 × 10−10 M), significantly exceeding that of other reactive oxygen species (ROS) ([SO4−] = 9.22 × 10−13 M, [OH] = 1.82 × 10−13 M). The dominant role of Co(IV)O in 4-CP degradation was further revealed through scavenger tests, probe methods, and electrochemical analysis. Additionally, the anti-interference of Co(IV)O in the degradation of electron-rich organic substrates to background constituents (NOM and halide ions) was systemically validated using three organic pollutants with different ionization potential values (diclofenac, 4-CP, and benzoic acid). This study provides insight into an efficient strategy for Co(IV)O -mediated pollutant elimination and organic substrate-dependent selectivity of Co(IV)O during water decontamination.

Diarylformamides as a safe reservoir and room temperature source of ultra-pure CO for a 'green' rWGS reaction.

Diarylformamides are shown to be a safe reservoir and source of CO. Perfectly selective decarbonylation is achieved in solution at room temperature with potassium and cesium diarylamide catalysts. Moreover,solvent-freedecarbonylations may be run either in a diphenylformamide melt at 70 ºC or, when the bisformamide9is used, in thesolid stateat 88 ºC in virtue of its improved atom economy. These These simple and practicaltransition-metal-freereactions afford ultra-pure (i.e.dry and solvent-free) CO at moderate temperatures and the byproduct diarylamines are recycled as pure compounds. In the absence of catalysts, diarylformamides1and9are long-term stable at > 200 ºC.DFT-calculations indicate a reaction pathway with a rate-determining deprotonation of Ph2NC(O)H and a barrier-free CO elimination from Ph2NC(O)-.

Theoretical Study of the Mechanism of the Formation of Azomethine Ylide from Isatine and Sarcosine and Its Reactivity in 1,3-Dipolar Cycloaddition Reaction with 7-Oxabenzonorbornadiene.

The reaction mechanism of tthe formation of azomethine ylides from isatins and sarcosine is addressed in the literature in a general manner. This computational study aims to explore the mechanistic steps for this reaction in detail and to assess the reactivity of formed ylide in a 1,3-dipolar cycloaddition reaction with 7-oxabenzonorbornadiene. For this purpose, density functional theory (DFT) calculations at the M06-2X(SMD,EtOH)/6-31G(d,p) level were employed. The results indicate that CO2 elimination is the rate-determining step, the activation barrier for 1,3-dipolar cycloaddition is lower, and the formed ylide will readily react with dipolarophiles. The substitution of isatine with electron-withdrawal groups slightly decreases the activation barrier for ylide formation.

Research on an in-situ synchronous CO elimination method in blasting operations and engineering experimental application based on nano-CO catalysts

The rapid and efficient elimination of CO by-products in mining and tunneling blasting operations poses a significant challenge. In this study, an in-situ synchronous elimination method (ISSE) for CO was proposed based on catalytic oxidation principles by deploying nano-scale catalysts in boreholes. Initially, Co3O4 catalyst was prepared and characterized. Subsequently, the catalyst was processed into a packing bag for in-situ CO elimination within boreholes. Field experiments were conducted at the Lujiatuo coal mine to verify the ISSE technology, and the effects of packaging materials, charging configuration, catalyst concentration, and length-to-diameter ratio of the packing bag on CO elimination efficiency were investigated. The experimental results revealed that when utilizing a nylon water cannon mud bag and charging 35 g of catalyst at the orifice, the peak CO concentration decreased from 735 ppm to 243 ppm, achieving an elimination efficiency of 66.9 % and reducing CO exceedance time by 28.5 %. These findings indicate that the ISSE technology surpasses existing techniques in terms of CO eliminating during mining and tunneling operations rapidly and effectively, that are expected to find widespread application in blasting production.

Oxygenation and Carbon Dioxide Rebreathing of a Well-fitting Non-rebreathing EcoLite™ Mask with a Reservoir: A Single-center Prospective Observational Study in Healthy Volunteers.

The fitting of oxygen mask affects the performance of it such as oxygenation or CO₂ elimination. The intersurgical EcoLite™ adult high-concentration oxygen mask (EcoLite with a reservoir, Intersurgical, UK) was developed to give well-fitting. The purpose of this study is to evaluate the performance of EcoLite with a reservoir compared to the conventional mask. Ten healthy volunteers were included in this study. EcoLite with a reservoir and conventional mask were given to patients at different oxygen flow rates (5, 8, 10, 12, and 15 L/min). Fraction of inspiratory O₂ (FIO₂) and partial pressure of inspiratory CO₂ (PICO₂) were measured by a sampling tube at the middle pharynx inserted via nose. The EcoLite with a reservoir had a significantly higher FIO₂ than the control reservoir mask. However, the PICO₂ was significantly higher in the EcoLite with a reservoir than in the control reservoir mask, especially when the oxygen flow rate was low. The EcoLite with a reservoir provided improved oxygenation and a better fit than the conventional reservoir masks in healthy volunteers. However, the EcoLite with a reservoir might cause higher CO₂ rebreathing at low oxygen flow rates.

Recent progress of Rh‐based three‐way catalysts

AbstractThree‐way catalysts are widely used to control criterion pollutant emissions from the increasing gasoline engines. With the stringent requirements of automotive pollutant emission standards in various countries, Rh has become an irreplaceable component of three‐way catalysts due to its superior NOx elimination, high N2 selectivity, and simultaneous elimination of CO and hydrocarbons. In this review, we systematically review the recent development of Rh‐based three‐way catalysts in terms of potential supports and effective active center construction strategies. We further summarize the key role of Rh metal in the three‐way catalytic mechanism and reaction kinetics. Finally, we conclude the current challenges and future opportunities facing Rh‐based catalysts. It is believed that based on the deep understanding of Rh‐based three‐way catalysts, the design of Rh‐based catalysts with good low‐temperature catalytic performance and low cost is expected to be realized in the future.

Efficient CO Oxidative Coupling to Dimethyl Oxalate over the Pd/Al2O3 Nanocatalyst with the Assistance of Co Doping

AbstractCO oxidative coupling to dimethyl oxalate (DMO) is an important approach for the product of ethylene glycol and CO elimination. In this work, the Co doped Pd/Al2O3 nanocatalyst was highly effective for CO oxidative coupling and enhanced remarkably CO conversion and the formation of DMO. The maximum DMO STY reached 1082 g L−1 h−1 over the Pd/Al2O3@1/20Co catalyst at 130 °C for 2 h under the space velocity of 3000 h−1, which is two times higher than that over the Pd/Al2O3 catalyst. The Co modification and its influence on the structure of the Pd/Al2O3 catalyst were also studied systematically by XRD, TEM, CO‐TPD, N2 physical adsorption and XPS techniques. An appropriate Co doing was confirmed to promote distinctly the generation of smaller Pd particles and the adjustment of the adsorption or activation of CO over the catalyst. A positive interaction between Pd nanoparticles and the modulated support with Co doping was demonstrated and favored the enhanced activity of the catalyst for the reaction.

Effect of cobalt on CeO2 nanorod supported Pt catalyst: Structure, performance, kinetics and reaction mechanism in CO oxidation

Catalytic oxidation represents a highly efficient and extensively employed approach for the elimination of CO in exhaust gas. Rationally designing and preparing catalysts with exceptional activity and stability in the presence of H2O and SO2 at low temperatures represent crucial avenues for future advancements. In this work, a series of Pt catalysts supported on CeO2 nanorods incorporated with varying amounts of Cobalt (Co/CeO2 ratio ranging from 0 to 10 %) were prepared and evaluated for their catalytic activity in CO oxidation under both dry and wet conditions. The ultrahigh dispersion of Pt, outstanding redox properties, and abundant oxygen vacancies on the surface of Co-doped CeO2 nanorod supported Pt catalysts were revealed by XRD, TEM, Raman spectroscopy and H2-TPR techniques. The catalytic activity for CO oxidation strongly depends on the Co content and reaction conditions. Among them, Pt/Co-CeO2-5 % exhibits the highest CO oxidation performance with a T90 (the temperature to achieve 90 % conversion of CO) of 170 °C under dry conditions, which is significantly lower by 140 °C compared to T90 of Pt/CeO2. Pt/Co-CeO2-1 % demonstrates superior CO oxidation performance with a T90 of 195 °C under wet conditions, exhibiting a reduction in temperature by 65 °C compared to the T90 of Pt/CeO2. Moreover, Pt/Co-CeO2 exhibits excellent resistance to SO2 compared to Pt/CeO2. Kinetic studies, in situ DRIFT analysis and isotopic experiments demonstrated direct participation of H2O in the reaction. On the catalysts with a low Co/Ce ratio (Co/Ce < 0.03), CO readily reacts with hydroxyl groups dissociated from H2O to form carboxyl intermediates, which subsequently undergo rapid decomposition into CO2, resulting in an enhanced reaction rate of CO oxidation at low temperature.

Revealing the poisoning effect of potassium salts on MnOx catalysts for low-temperature simultaneous removal of NO and CO

Simultaneously elimination of NO and CO in the sintering flue gas is an urgent problem, in which the application of the bifunctional MnOx catalyst has demonstrated its effectiveness in removing NO and CO simultaneously. Potassium salts are frequently found in the sintering flue gas and exert a detrimental influence on the catalytic performance of catalysts. Herein, the primary focus of this study is to investigate different K+ species (K2SO4, KCl, KNO3) poisoning effect on bifunctional MnOx. The findings suggested a deactivation order in the sequence of KNO3 > KCl > K2SO4. Fresh Mn-AC catalyst had finer grains, and poisoning elements were evenly distributed. XPS results revealed an obvious decrease in Mn4+ and Oβ species across all catalysts after K+ species poisoning, hindering redox cycle activation and oxygen species mobility, thus impacting catalytic activity. The in situ DRIFTS results indicated the forbidden of E-R route over KNO3-poisoned catalysts and low reactivity of adsorbed species after poisoning for NO removal. KNO3 severely suppressed surface reaction paths on Mn-AC catalyst and declined the catalytic efficiency, especially in CO activation. Finally, a possible reaction mechanism model for the simultaneous removal of NO and CO was proposed. This study could provide reference for the development of bifunctional catalyst with high resistance to potassium salts.

Unimolecular Fragment Coupling: A New Bond-Forming Methodology via the Deletion of Atom(s).

Unimolecular fragment coupling (UFC) is defined as a reaction format, wherein atom(s) located in the middle of a molecule are extruded, and the remaining fragments are coupled. UFC is a potentially powerful strategy that is an alternative to transition-metal-catalyzed cross-coupling because the target chemical bond is formed in an intramolecular fashion, which is inherently beneficial for chemoselectivity and stereoselectivity issues. In this Perspective, we will present an overview of the recent advances in UFC reactions, which encompass those proceeding through the elimination of CO2, CO, SO2, isocyanates, N2, or single atoms primarily via transition metal catalysis.

Prediction Challenge: Simulating Rydberg photoexcited cyclobutanone with surface hopping dynamics based on different electronic structure methods.

This research examines the nonadiabatic dynamics of cyclobutanone after excitation into the n → 3s Rydberg S2 state. It stems from our contribution to the Special Topic of the Journal of Chemical Physics to test the predictive capability of computational chemistry against unseen experimental data. Decoherence-corrected fewest-switches surface hopping was used to simulate nonadiabatic dynamics with full and approximated nonadiabatic couplings. Several simulation sets were computed with different electronic structure methods, including a multiconfigurational wavefunction [multiconfigurational self-consistent field (MCSCF)] specially built to describe dissociative channels, multireference semiempirical approach, time-dependent density functional theory, algebraic diagrammatic construction, and coupled cluster. MCSCF dynamics predicts a slow deactivation of the S2 state (10ps), followed by an ultrafast population transfer from S1 to S0 (<100fs). CO elimination (C3 channel) dominates over C2H4 formation (C2 channel). These findings radically differ from the other methods, which predicted S2 lifetimes 10-250 times shorter and C2 channel predominance. These results suggest that routine electronic structure methods may hold low predictive power for the outcome of nonadiabatic dynamics.