Efficient CO2 Removal Research Articles

Biomimetic Gas Channel Constructed for Efficient CO2 Removal Based on Computational Simulations

Membrane oxygenator performs lung function in the Extra-corporeal Membrane Oxygenation (ECMO) system. In the clinical use, to ensure the balance of gas exchange of patient’s body, the gas-blood exchange membrane is required to possess CO2/O2 selectivity, which is suggested to be in the range of 10-12. In our work, the molecular dynamics simulation results displayed that the amino-functionalized Zr-MOFs provides fast transport channels for CO2 molecules because of the enhancement of the adsorption and diffusion ability for CO2. Therefore, we chose organic ligands with abundant CO2-philic groups to synthesize target amino-functionalized Zr-MOFs, and then dispersed them into medical-grade PDMS solution to study the separation performance of CO2/O2. On the basis of constructing anti-leakage coating layer, biomimetic gas channels were designed to increase the clearance rate of CO2. Experimental results exhibited that the CO2/O2 selectivity of (NH2)2-UiO-66/PDMS MMM was as high as 11.19, which was basically consistent with the simulation results. The obtained amino-functionalized Zr-MOF/PDMS coating layer displayed favorable biocompatibility and biosafety. Meanwhile, the construction of biomimetic channel solves the difficult problem of CO2 removal in PMP membrane, which verifies the feasibility of applying porous materials to gas-blood exchange membranes in the ECMO system.

Novel synthesis and application of zeolite-Y from waste clay for efficient CO2 capture and water purification

In the present study, the microwave-assisted hydrothermal method using sodium hydroxide (NaOH) has been used to synthesise zeolite-Y from three different waste clays (WC) from Teesside, Northeast of England, UK. The effects of microwave time intervals and WC type were investigated to produce crystalline zeolite-Y. All WCs and synthesised zeolites were characterised by scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller surface area measurement (BET). The characterisation results showed that the zeolite-Y samples synthesised at 6 min intervals exhibited larger total pore volumes, higher surface areas, and higher crystallinity compared to the samples synthesised at 4 min intervals. Especially, the synthesised zeolite-Y from Clay 1 displayed high CO2 adsorption capacity, achieving 5.23 mmol/g at 298 K and 1 bar, with a maximum methylene blue removal of 94.3 %. This sample showed a surface area of 485 m²/g and a pore volume of 0.24 cm³/g, alongside an Si/Al ratio of 3.7, highlighting its excellent thermal stability at elevated temperatures. The high CO2 adsorption capacity combined with the high methylene blue removal efficacy makes the synthesised zeolite-Y from WC an excellent candidate for efficient CO2 capture and removal of methylene blue from contaminated water. Additionally, this study illustrates the potential for waste valorisation through the conversion of low-value WC into high-performance, value-added materials. This transformation not only mitigates waste disposal issues but also contributes to sustainable resource management and environmental protection by offering a practical solution for treating industrial effluents and gas emissions.

Enhancement of CO2 removal from flue gas in an oscillatory baffled column using potassium carbonate solution

One of the efficient methods for reducing CO2 emissions from flue gas streams in oil refineries and power plants is the CO2absorption process using alkali solution. Potassium carbonate (K2CO3) solution, as CO2 absorbent, was used in the present study due to its high CO2 absorption capacity. However, K2CO3 has a drawback which is represented by its slow reaction with CO2. To overcome this issue, an oscillatory baffled column (OBC) was utilized as a contactor to maintain a high degree of mixing in the CO2 absorption system and thereby increasing the reaction rate between K2CO3 and CO2 as well as enhancing the mass transfer rate. In this study the effect of different operation conditions of the process namely; inlet flue gas flow rate (15 % (v/v) CO2 balanced with N2) and oscillation conditions on CO2 absorption in a semi-batch OBC were investigated. The experiments were performed with range of modified Reynolds Number of Oscillation (Reo′ = 0⎼1450) and aeration rates (0⎼1 vvm) using K2CO3 (100 g/L, 0.72 M)0.1.8–3.5-fold of enhancement of CO2 absorption rates was achieved by using OBC with respect to that obtained by baffled column (BC) (only baffles without oscillation) and plane bubble column (PBC) (without baffles and oscillation), respectively.The use of K₂CO₃ as a solvent in an oscillating reactor (OBR) to remove CO₂ represents a new method due to the high reactivity of K₂CO₃ with CO₂, forming stable bicarbonate and carbonate compounds. OBR's enhanced mixing capabilities improve mass transfer rates and reaction efficiency, allowing for more effective CO2 capture compared to conventional reactors. This combination leverages the strengths of both the chemical reactivity of K₂CO₃ and the mechanical benefits of OBR, potentially leading to more efficient and scalable CO2 removal processes.

Geospatial assessment of the cost and energy demand of feedstock grinding for enhanced rock weathering in the coterminous United States

In an effort to mitigate anthropogenic climate impacts the U.S. has established ambitious Nationally Determined Contribution (NDC) targets, aiming to reduce greenhouse gas emissions by 50% before 2030 and achieving net-zero emissions by 2050. Enhanced rock weathering (ERW)—the artificial enhancement of chemical weathering of rocks to accelerate atmospheric CO2 capture—is now widely seen as a potentially promising carbon dioxide removal (CDR) strategy that could help to achieve U.S. climate goals. Grinding rocks to smaller particle size, which can help to facilitate more rapid and efficient CO2 removal, is the most energy-demanding and cost-intensive step in the ERW life cycle. As a result, accurate life cycle analysis of ERW requires regional constraints on the factors influencing the energetic and economic demands of feedstock grinding for ERW. Here, we perform a state-level geospatial analysis to quantify how carbon footprints, costs, and energy demands vary among regions of the coterminous U.S. in relation to particle size and regional electricity mix. We find that CO2 emissions from the grinding process are regionally variable but relatively small compared to the CDR potential of ERW, with national averages ranging between ~5–35 kgCO2 trock−1 for modal particle sizes between ~10–100 μm. The energy cost for feedstock grinding also varies regionally but is relatively small, with national average costs for grinding of roughly 0.95–5.81 $ trock−1 using grid mix power and 1.35–8.26 $ trock−1 (levelized) for solar PV for the same particle size range. Overall energy requirements for grinding are also modest, with the demand for grinding 1 Gt of feedstock representing less than 2% of annual national electricity supply. In addition, both cost and overall energy demand are projected to decline over time. These results suggest that incorporating feedstock grinding into ERW deployment at scale in the coterminous U.S. should generally have only modest impacts on lifecycle emissions, cost-effectiveness, and energy efficiency.

Efficient CO2 removal enabled by N, S co-doped hierarchical porous carbon derived from sustainable lignin

Biomass-derived heteroatoms-doped hierarchical porous carbon materials are highly regarded as promising CO2 adsorbents. However, these materials cannot simultaneously exhibit advanced porosity, high yield, and high heteroatom content. Herein, a series of N, S co-doped hierarchical porous carbons with advanced porosity (narrow micropore: 0.37–0.42 cm3/g), high heteroatom content (N content: 8.54 at% and 8.87 wt% and S content: 0.86 at% and 1.73 wt%) and remarkable yield (57.12–69.13 wt%) was produced using lignin as the raw material via a synergistic strategy involving melamine modification and CuCl2 activation. Notably, melamine modification not only introduced mesopores, but also promoted the effect of CuCl2 activation to generate additional micropores. Importantly, the advanced porosity required a low dosage of CuCl2. The optimized adsorbent (NHPC-850) exhibits outstanding CO2 adsorption capacity (6.87 mmol/g at 273 K and 100 kPa, 3.57 mmol/g at 303 K and 100 kPa), a moderately high heat of adsorption (34.7 kJ/mol), and an extraordinary CO2/N2 selectivity (132 at 273 K/81 at 303 K). These excellent properties are attributed to the well-developed micropores and suitable mesopores of carbon materials, as well as rich nitrogen and sulfur functionality in the carbon structure. Collectively, this work offers new insights into a simple and easy-to-scale strategy for the preparation of biomass-derived N, S co-doped hierarchical porous carbon.

Facile Synthesis of Self-Supported Solid Amine Sorbents for Direct Air Capture.

Conventional usage of tetraethylenepentamine (TEPA) via being supported on porous solid materials for carbon capture is susceptible to oxidative degradation during regeneration cycles. This study reports a novel method to synthesize a TEPA based solid polymer for efficient CO2 removal via direct air capture (DAC). The polymer was obtained through epoxy-amine crosslinking reaction, leading to the transformation of liquid TEPA to a self-supported solid polymer. The synthesis was conducted under ambient conditions via a one-pot process with no waste products, which is aligned with green synthesis. The performance of the solid amine was evaluated in DAC under realistic conditions and compared with TEPA supported on SiO2 and zeolite 13X prepared through the conventional method. The solid TEPA amine exhibited a high CO2 uptake of 6.2 wt.% comparable to the conventional counterparts. More importantly, the solid TEPA amine demonstrated high resistance to oxidation during the accelerated ageing process at 80 °C in air for 24 h, whereas the two supported TEPA samples experienced severe degradation, with zeolite 13X supported TEPA incurring a reduction of 86.5 % in CO2 capturing capacity after the ageing. This work sheds light on the novel usage of TEPA as an efficient solid amine for practical DAC operation.

Aiming at the valorization of CO2 through its capture by simply extruded high cell-density coal honeycombs

Integral coal honeycomb monoliths were easily prepared achieving the cell densities typical of commercial cordierites through extrusion plus physical activation. Different techniques such as volumetric adsorption, TGA, TPD and transient kinetic analysis were employed to study their interaction with CO2 at different temperatures (35–100 °C) and under both static and dynamic atmosphere. The CO2 capture capacity resulted to be 0.95 mmol/g at 35 °C, much higher than that of previously studied clay honeycomb adsorbents. The CO2 uptake exhibited fast second order kinetics, and a wide operative window for a highly efficient CO2 removal was found. Moreover, due to a weak interaction, most CO2 adsorbed could be released at 110 °C, what allows minimizing the costs related to controlled regeneration if ones wants to reuse the captured CO2 but at the same time prevents from desorption when this is undesirable. Treatment of the coal honeycomb monolith with a 1:1 CO2+CH4-containing stream revealed, through gas chromatography analysis, the conversion into syngas at relatively low temperatures (50% at 750 °C) in spite of the metal-free character of the monolith. Moreover, this activity reached 90% and remained quite stable for at least 12 h at 900 °C. These results demonstrate the potential of preparing honeycomb monoliths from coal as a strategy to diversify the uses of this abundant natural resource and as an alternative in the field of CO2 capture and valorization.

Oxygen-enriched carbon molecular sieve hollow fiber membrane for efficient CO2 removal from natural gas

Natural gas is considered one of the most attractive low carbon energy sources while the separation of CO2 is a crucial process for the natural gas purification. Herein, cellulose-based carbon molecular sieve (CMS) hollow fiber membranes with high CO2 affinity capability were fabricated through a post-treatment strategy of hydrogen-induced reduction followed by oxygen-doped modification (H-O treatment), and show good potential for high pressure natural gas purification. The CMS membranes were reduced by H2 at high temperatures (500–600 °C) to form active sorption sites in the carbon matrix, and subsequently chemically absorbed O2 to generate oxygen-containing functional groups, which are favorable for CO2 adsorption and diffusion. After being treated at 600 °C (CMS-600), the CMS membrane presented a high CO2 adsorption capacity of 62.78 cm3/g (298 K). As a result, the CO2 permeability was enhanced from 264 to 1125 Barrer, with approximately 400 % improvement. Moreover, mixed gas separation performances (CO2/N2 and CO2/CH4) were investigated at high pressure and impurities feedings. The CMS membrane exhibited a remarkable CO2/CH4 separation factor of 104 when operated at 20 bar and 500 ppm heptane existed.

Graphene Oxide/Melamine/Ionic liquid membranes for selective CO2 separation

Highly permeable and selective membranes with long-term stability are needed to reduce operating and capital costs of industrial gas-separation units. In this study, we fabricate new membranes made of melamine (M)- and imidazolium-based ionic liquid (IL)-modified graphene oxide (GO) deposited on a porous support and buried with a polydimethylsiloxane (PDMS) layer. The CO2/N2 and CO2/CH4 ideal selectivities of the composite membranes are respectively 65 % and 70 % higher than those of the membranes containing only the IL. This significant improvement in ideal selectivity is attributed to synergic effects of nanochannels created by GO, fixed facilitated transport provided by the IL and numerous amine groups in the melamine structure, and the increased polarity of the membrane caused by the presence of the IL. The composite membrane has a pure CO2 permeance of 47 GPU with a high CO2/N2 ideal selectivity of 109 and a satisfactory CO2/CH4 ideal selectivity of 39. The composite membrane maintains stable performance over a 60-hour operation, highlighting its long-term reliability. The outstanding performance, coupled with the ease of fabrication, underscores the potential of these composite membranes for practical and efficient CO2 removal from both natural and flue gas streams in real-world applications.

Efficient adsorptive removal of Co2+ from aqueous solution using graphene oxide.

This study aimed to utilize synthesized graphene oxide (GO) for adsorptive removal of cobalt ions and investigate the adsorption mechanism using advanced techniques such as X-ray absorption spectra (XAFS). The GO was synthesized via an improved Hummers method, resulting in high surface area (93.7 m2/g) and abundant oxygen-containing functional groups. Various characterizations, including SEM, TEM, Raman, FT-IR, TG, potentiometric titrations, and N2 sorption-desorption measurements, were employed to characterize the GO. The adsorption behavior of GO towards Co2+ was investigated, and the results showed that the adsorption process followed a pseudo-second-order kinetic model and the Langmuir model, with a maximum sorption capacity of 93.7 mg/g. The adsorption process was chemisorption and endothermic, with GO showing adsorption selectivity order of Co2+ > Sr2+ > Cs+. Based on various characterizations such as X-ray absorption near-edge spectroscopy (XANES), extended X-ray absorption fine structure (EXAFS), FT-IR, and XPS, the sorption mechanism of Co2+ onto GO was discussed, with the results indicating that coordination and electrostatic interaction were the primary adsorption mechanisms, with oxygen-containing functional groups playing a vital role. The first coordinating atom for Co2+ was O, and the coordination environment was similar to that of cobalt acetate and CoO. Overall, this study provides comprehensive understanding of the adsorption behavior and mechanism of Co2+ onto GO, highlighting its potential as an effective adsorbent for removing nuclides from aqueous solution.

Theoretical and experimental study of CO2 removal from biogas employing a hollow fiber polyimide membrane

In the present work, the efficient removal of CO2 from CH4 for biogas upgrade is investigated, employing a commercial polyimide (PI) membrane (UBE Industries Ltd., Japan). The goal is to meet the requirements of high purity biomethane (>95%) for effective energy use (e.g., by connecting the CH4-rich gaseous stream into the natural gas grid) with simultaneous CO2 capture, for potential reuse. The separation process is studied experimentally employing a commercial hollow fiber polyimide membrane module at laboratory scale conditions, while mathematical process models of various complexity in terms of the flow conditions are employed and compared with the experiments. The results demonstrate that, among the different flow models, the crossflow model is in much better agreement with the experimental results and can be further employed to design more complex membrane module configurations, such as two- and three-stage processes, recycle, etc.

3D-hierarchical porous functionalized carbon aerogel from renewable cellulose: An innovative solid-amine adsorbent with high CO2 adsorption performance

A novel solid amine sorbent has been developed based on polyethylenimine (PEI)-grafted monolithic porous carbon aerogel supports for efficient removal of CO2 from industrial flue gas at 313K. The high pore volume, proper pore distribution and the interconnected 3D framework of monolithic porous carbon aerogel allow the easy dispersion of PEI and ensure the diffusion of CO2 in its pore structure. In addition, the monolithic porous structure can reduce the influence of the pressure difference of large fixed bed on the adsorption performance in industrial applications. More importantly, the reasonable design of pore effect and functionalized molecular configuration of PEI grafted cellulose based porous carbon aerogel (PEI-CPCa) guarantees the maximization of synergistic effect thus may achieve the efficient separation of CO2 from industrial flue gas. Results shows that the CO2 adsorption capacity of PEI-CPCa reached 5.58 mmol/g and the separation coefficient reached 113.1 at 313K for simulated gas consisting of CO2 (15 vol%) and N2 (85 vol%). Furthermore, the low energy consumption, excellent stability and water resistance of the PEI-CPCa make it possess great prospects and advantages in practical industrial applications. Comprehensively, this new functional carbon aerogel is a highly efficient and environmentally friendly adsorbent for the adsorption and separation of CO2.

Incorporation of a pyrrolidinium-based ionic liquid/MIL-101(Cr) composite into Pebax sets a new benchmark for CO2/N2 selectivity

Mixed matrix membranes (MMMs) offer a broad potential for energy efficient removal of CO2 from flue gas and natural gas. In this study, we synthesized a novel ionic liquid (IL)/metal organic framework (MOF) composite, [MPPyr][DCA]/MIL-101(Cr), where [MPPyr][DCA] is 1-methyl-1-propyl pyrrolidinium dicyanamide, and incorporated it as a filler into Pebax to fabricate IL/MOF/polymer MMMs. The superior solubility of CO2 in the [MPPyr][DCA] and the strong interactions between IL and CO2 molecules boost the CO2 selectivity of the membrane over N2 and CH4. The results showed that CO2permeability of the MMM having 15 wt.% [MPPyr][DCA]/MIL-101(Cr) composite as the filler (148 Barrer) was similar to that of pure Pebax membrane (134 Barrer), while the ideal CO2/N2selectivity (1347) and ideal CO2/CH4 selectivity (122) of the MMM were 45- and 10-times higher compared to the selectivities of pure Pebax membrane, respectively. To the best of our knowledge, the remarkable enhancement in the CO2/N2 selectivity of the MMM sets a new benchmark value for the IL/MOF/polymer MMMs in the literature. These results demonstrate the great potential of using [MPPyr][DCA]/MIL-101(Cr) composite as a filler for the fabrication of highly selective IL/MOF/polymer MMMs for CO2/N2 and CO2/CH4 separations.

Mixed matrix composite membranes with MOF-protruding structure for efficient CO2 separation

Mixed matrix composite membranes (MMCMs) hold great potential to realize efficient CO2 removal from natural gas. However, the reduction of separation performance arising from the interfacial defects, significant plasticization and aging effect in the thin films severely limit their application. Herein, we fabricated a series of polyimide MMCMs with MOF-protruding structure wherein amino-functionalized ZIF-8 nanocrystals nearly penetrate the thin selective layer. Through engineering the interfacial interactions, e.g., covalent or hydrogen bondings, we successfully fabricated defect-free MMCMs with the thickness ranging from 140 to 280 nm. The stronger interfacial interactions eliminate the interfacial defects and restrict the mobility of polymer chains under high pressure. Accordingly, the MMCM displays a high CO2 permeance of 778 GPU and a CO2/CH4 selectivity of 34 with significantly improved resistance to plasticization and aging. Considering the superior performance, we anticipate our work could provide guidelines on designing advanced MMMs to tackle critical separations.

Ionic resource recovery for carbon neutral papermaking wastewater reclamation by a chemical self-sufficiency zero liquid discharge system

Papermaking industry discharges large quantities of wastewater and waste gas, whose treatment is limited by extra chemicals requirements, insufficient resource recovery and high energy consumption. Herein, a chemical self-sufficiency zero liquid discharge (ZLD) system, which integrates nanofiltration, bipolar membrane electrodialysis and membrane contactor (NF-BMED-MC), is designed for the resource recovery from wastewater and waste gas. The key features of this system include: 1) recovery of NaCl from pretreated papermaking wastewater by NF, 2) HCl/NaOH generation and fresh water recovery by BMED, and 3) CO2 capture and NaOH/Na2CO3 generation by MC. This integrated system shows great synergy. By precipitating hardness ions in papermaking wastewater and NF concentrate with NaOH/Na2CO3, the inorganic scaling on NF membrane is mitigated. Moreover, the NF-BMED-MC system with high stability can simultaneously achieve efficient CO2 removal and sustainable recovery of fresh water and high-purity resources (NaCl, Na2SO4, NaOH and HCl) from wastewater and waste gas without introducing any extra chemicals. The environmental evaluation indicates the carbon-neutral papermaking wastewater reclamation can be achieved through the application of NF-BMED-MC system. This study establishes the promising of NF-BMED-MC as a sustainable alternative to current membrane methods for ZLD of papermaking industry discharges treatment.

Superior selective adsorption of trace CO2 induced by chemical interaction and created ultra-micropores of ionic liquid composites

Effective capture of trace CO2 in atmosphere or confined spaces to ensure human beings safety draw a lot of attention, however, how to simultaneously improve CO2 capacity and selectivity still faces great challenge. Herein, combining porous molecular sieves (SBA-15 and MCM-41) and the anion-functionalized ionic liquid (IL) tetraethylammonium glycinate ([N2222][Gly]), a series of hierarchically porous IL composites with different IL loadings were designed and prepared. Compared with pristine supports, the incorporation of [N2222][Gly] simultaneously improves CO2 capacity and CO2/N2 selectivity by ordersofmagnitude, especially for confined spaces (<5000 ppm) and air (415 ppm). When the IL loading was 60 wt%, novel micropores were created, especially ultra-micropores (<0.65 nm), which are not present in bare supports and other [N2222][Gly]@SBA-15 (15, 30 and 45 wt%). Among them, 60 wt%[N2222][Gly]@SBA-15 showed the highest CO2 uptake of 1.45 and 1.88 mmolCO2/g-adsorbent at 0.0005 and 0.005 bar under 313 K along with recyclability, which are much superior to the state-of-the-art reported values. Moreover, superb ideal CO2/N2 selectivity of 11,545 at 0.005 bar and 288 K was achieved, which was 288 times that of SBA-15. Meanwhile, mixed gas breakthrough experiments demonstrated that 60 wt% [N2222][Gly]@SBA-15 shows outstanding CO2 separation performance under simulative confined spaces and ambient air. The ultra-high CO2 separation performance was attributed to the synergy of chemical interaction between the IL anion and CO2 as well as newly created micro- and ultra-micropores effect. This work provides guidelines for the design of IL composites with ultra-micropores for efficient trace CO2 removal.

Exhaust gas recirculation effects on flame heat release rate distribution and dynamic characteristics in a micro gas turbine

Exhaust gas recirculation (EGR) is an option proposed to augment the CO2 content in the exhaust gas for the efficient removal of CO2. In the field of micro-gas turbine (MGT), EGR is also a feasible solution to improve the part-load performance and fuel flexibility. This research combined EGR with an adjustable fuel feeding combustor to assess the part-load performance of a 300 kW MGT and the flame spatiotemporal characteristics. The radical chemiluminescence intensity of hydroxyl is selected to represent the heat release rate (HRR) in natural gas flames. The influence of EGR on HRR was investigated experimentally under various load ratios (50%–100%) and EGR ratios (0–20%). In addition, the temperature at the combustion chamber outlet is also measured. The results show that EGR can effectively reduce OTDF when the load ratio is high. Both the spatial distribution non-uniformity and fluctuation amplitude of HRR are suppressed after applying EGR. And EGR can also reduce the influence of mixing on HRR spatiotemporal characteristics. At last, the frequency characteristics of HRR are analyzed. The result shows that the flame frequency has a strong correlation with the characteristic frequency of turbulence.

Airway pressure release ventilation versus pressure-controlled ventilation in acute hypoxemic respiratory failure

Background Airway pressure release ventilation (APRV) is defined as ventilation modality with triggered time, limited pressure, and cycled time. In this mode, the pressure altered from a high level applied for a prolonged time to maintain adequate lung volumes and alveolar recruitment, to a low level for a short period of time that allows efficient ventilation and CO2 removal. Patients and methods Patients with acute hypoxemic respiratory failure were mechanically ventilated, and then, shifted to either synchronized intermittent mandatory ventilation, pressure control (group I) or to APRV (group II). The following parameters were monitored and compared: arterial blood gas measurements, hemodynamic, respiratory mechanics, peak pressure, plateau pressure, mean airway pressure, compliance, minute ventilation, indices of hemodynamic, and tissue perfusion. Results This study involved 60 mechanically ventilated patients. Our study demonstrated no significant difference between both groups regarding demographic data. We found that APRV group have better hemodynamic, better oxygenation, lower need for sedation and vasopressors, higher cardiac index, and higher estimated glomerular filtration rate. ICU scores were comparable in both groups, whereas lung injury score significantly decreased with APRV mode in APRV group. Decreased duration of mechanical ventilation, ICU stay, hospital stay, less complication risk, and less mortality rate were seen with APRV mode. Conclusion The early application of APRV in patients with acute severe hypoxemic respiratory failure was associated with better hemodynamic, better oxygenation, better respiratory mechanics, less sedation use, better perfusion, lower risk of complication, and a shorter duration of ICU stay. Future research should compare APRV strategies to assign the best management approach.

Extracorporeal carbon dioxide removal with the Advanced Organ Support system in critically ill COVID-19 patients.

Disturbed oxygenation is foremost the leading clinical presentation in COVID‐19 patients. However, a small proportion also develop carbon dioxide removal problems. The Advanced Organ Support (ADVOS) therapy (ADVITOS GmbH, Munich, Germany) uses a less invasive approach by combining extracorporeal CO2‐removal and multiple organ support for the liver and the kidneys in a single hemodialysis device. The aim of our study is to evaluate the ADVOS system as treatment option in‐COVID‐19 patients with multi‐organ failure and carbon dioxide removal problems. COVID‐19 patients suffering from severe respiratory insufficiency, receiving at least two treatments with the ADVOS multi system (ADVITOS GmbH, Munich, Germany), were eligible for study inclusion. Briefly, these included patients with acute kidney injury (AKI) according to KDIGO guidelines, and moderate or severe ARDS according to the Berlin definition, who were on invasive mechanical ventilation for more than 72 hours. In total, nine COVID‐19 patients (137 ADVOS treatment sessions with a median of 10 treatments per patient) with moderate to severe ARDS and carbon dioxide removal problems were analyzed. During the ADVOS treatments, a rapid correction of acid‐base balance and a continuous CO2 removal could be observed. We observed a median continuous CO2 removal of 49.2 mL/min (IQR: 26.9‐72.3 mL/min) with some treatments achieving up to 160 mL/min. The CO2 removal significantly correlated with blood flow (Pearson 0.421; P < .001), PaCO2 (0.341, P < .001) and HCO3‐ levels (0.568, P < .001) at the start of the treatment. The continuous treatment led to a significant reduction in PaCO2 from baseline to the last ADVOS treatment. In conclusion, it was feasible to remove CO2 using the ADVOS system in our cohort of COVID‐19 patients with acute respiratory distress syndrome and multiorgan failure. This efficient removal of CO2 was achieved at blood flows up to 300 mL/min using a conventional hemodialysis catheter and without a membrane lung or a gas phase.

Separation of Carbon Dioxide by Potassium Carbonate based Supported Deep Eutectic Liquid Membranes: Influence of Hydrogen Bond Donor

This article focuses on the study of potassium carbonate (PC) based deep eutectic solvents based supported liquid membranes (DES-SLMs) for CO2 capture. A new class of green solvent was impregnated into microporous polyvinylidene fluoride (PVDF) membrane for the separation of CO2. Two types of DESs were synthesized by mixing and heating PC with glycerol or ethylene glycol separately. The novelty of this study lies in the exploitation of PC-DESs in the PVDF membrane. The mechanism of interaction was inferred from the spectral analysis (FTIR) whereas thermal analysis (TGA) was performed to analyze the stability of the prepared membrane. Experiments were performed to analyze the permeability and selectivity of the membranes. The results showed that PC-Glycerol based SLM exhibited permeability of 34.55 Barrer and ideal selectivity of 59.57 while PC-Ethylene Glycol based SLM exhibited permeability of 20.23 Barrer and ideal selectivity of 34.29 under similar operating conditions. Systematic analysis was made for some of the important operating parameters affecting the separation performance such as temperature and feed composition. Comparison was made between the performance of PC-DES-SLMs and conventional imidazolium based SILMs on the well-known Robeson’s upper bound plot. The current efforts of exploitation of PC-DES membrane will lead to new prospective for the efficient removal of CO2 from the industrial gas mixture.