Industrial Flue Gas Research Articles

A modified semi-empirical model for correlating and predicting CO2 equilibrium solubility in aqueous 2-[2-(dimethylamino)ethoxy]ethanol solution

Amine-based post-combustion capture is considered an effective method to control CO2 emissions from industrial flue gases, but some improvements are still needed for its widespread use. Looking for low-corrosive sorbents for steel, we decided to investigate the properties of the tertiary amine 2-[2-(dimethylamino) ethoxy] ethanol (DMAEE), and in particular its CO2 equilibrium solubility at temperature in the range 298.15–323.15 K and CO2 partial pressure between 5.0 and 60 kPa. A correction factor based on the physical solubility was applied to modify the Kent-Eisenberg model and then to predict the CO2 solubility in DMAEE solution, and the absolute average deviation (AAD) between the prediction and the experimental data was found to be 3.0%, lower than that obtained by reported Kent-Eisenberg, Austgen, Hu-Chakma, and Li-Shen models. The proposed model was then further correlated with published solubility data of four other tertiary amines, and the results indicate that the proposed semi-empirical model can be used for these amines with acceptable AADs. In addition, the heat of CO2 absorption and the dissociation constant (pKa) were also systematically evaluated and compared with other reported amines, and the obtained results indicate that DMAEE has the potential to be a suitable absorbent for post-combustion CO2 capture.

A Robust Squarate-Cobalt Metal-Organic Framework for CO2/N2 Separation.

The separation of CO2 from the industrial post-combustion flue gas is of great importance to reduce the increasingly serious greenhouse effect, yet highly challenging due to the extremely high stability, low cost, and high separation performance requirements for adsorbents under the practical operating conditions. Herein, we report a robust squarate-cobalt metal-organic framework (MOF), FJUT-3, featuring an ultra-small 1D square channel decorated with -OH groups, for CO2/N2 separation. Remarkably, FJUT-3 not only has excellent stability under harsh chemical conditions but also presents low-cost property for scale-up synthesis. Moreover, FJUT-3 shows excellent CO2 separation performance under various humid and temperature conditions confirmed by the transient breakthrough experiments, thus enabling FJUT-3 with adequate potentials for industrial CO2 capture and removal. The distinct CO2 adsorption mechanism is well elucidated by theoretical calculations, in which the hierarchical C···OCO2, C-O···CCO2, and O-H···OCO2 interactions play a vital synergistic role in the selective CO2 adsorption process.

Silicon assisted synthesis of high-purity Ca3Al2O6 carrier towards scale-up of Ca-based carbon dioxide capture materials

Aluminium-stabilized calcium-based materials are currently an excellent solution for capturing CO2 directly from industrial flue gas. However, there is still no report on the technology of low-cost and large-scale assembly of Ca3Al2O6 and CaO. In this study, we innovatively put forward a silicon-assisted strategy to facilely synthesize high-purity Ca3Al2O6 and evaluate its cyclic performance for stabilizing uptake CO2 after assembly. With regard to the Si/Al ratio of 0.2, Ca3Al2O6 was prepared selectively among 850–900 °C, with only 5.2% CaO residually. The introduction of silicon inhibited the formation of Ca5Al6O14 by-products and the mechanism of silicon at the calcium-aluminum interface was also explained by systematic characterization. The Ca3Al2O6 modified sorbent with simple assembly showed extremely high cycle stability improvement compared with the pure precipitated calcium carbonate derived CaO. These works provide technical guidance for the industrial scale-up of the rational design of Al-stabilized calcium-based adsorption materials.

Molecular modeling of gaseous mercury species adsorption and transport in nanoporous silica membranes

The separation of Hg and HgO from industrial flue gas is an issue of much interest in the control of heavy metal emissions, and its feasibility for kinetic and equilibrium separation of Hg and HgO from N2 using disordered silica is theoretically investigated here using a combination of pore level transport modelling and effective medium theory. It is found that the classical Knudsen model generally leads to considerable over-prediction of the effective diffusion coefficient in the nanoporous silica compared to the more accurate Oscillator model that considers fluid–solid interaction. It is seen that nanoporous silica membranes are kinetically selective to nitrogen, the major component of flue gas, relative to Hg and HgO. Nevertheless, the kinetic selectivity for N2 is low, and only about 2–3, indicating that the kinetic separation of mercury species from flue gas is not practically feasible. On the other hand, the equilibrium selectivity of HgO over N2 is over 50 at 0.75 nm modal radius, while that for Hg exceeds 30 at 0.3 nm radius, suggesting this method of separation to be appropriate. Narrow pore silica materials of uniform nanopore size of about 0.3–0.75 nm are found to be optimal for the removal of mercury species.

Carbon dioxide capture from industrial flue gas surrogate by multi-cyclical PSA mediated by microporous palm kernel shell and ZIF-8 media

This study explores the application of microporous APKS and ZIF-8 adsorbents for carbon dioxide capture from flue gas surrogate. The purity and recovery of N2 and CO2 in the product and waste stream were simulated and experimented in the lab. The experimental breakthrough at different N2/CO2 stream adsorption compositions validated the Aspen adsorption model. Results from the simulation show that in the product stream, factors such as adsorbent type (APKS), lower adsorption times, and low CO2 concentration in the feed led to improved N2 purity. On the other hand, results from the experiment show that the CO2 feed compositions, type of adsorbent and cyclical pressure swing operation correlated significantly with the purity and recovery of the CO2 in the waste stream. Interestingly, as previously understood, the high surface area was important but not a guarantee to achieve the highest product purity. The highest CO2 purity of 83% was obtained using APKS. In contrast, the highest CO2 recovery of 65% was obtained by ZIF-8. The degraded performance at the increasing cycle was due to the inability of both porous media to regenerate completely, causing product contamination and blockages of the CO2 affinitive sites of the adsorbents from capturing the gas effectively.

Boosting the CO2 adsorption performance by defect-rich hierarchical porous Mg-MOF-74

Adsorbents with high adsorption capacity and high selectivity are crucial for carbon capture, utilization and storage (CCUS) technology applied to industrial flue gas to reduce carbon emissions. In this paper, a defect-rich hierarchical porous Mg-MOF-74 was synthesized successfully with MgCl2·6H2O used as a metal source considering that the weak coordination of Cl− may interfere with the normal coordination process of metal centers and organic ligands, which causes the formation of crystal defects. Through the analysis of a series of characterizations, ligand deletion of Mg-MOF-74 prepared with MgCl2·6H2O was confirmed, and the deleted ligand was estimated to be approximately 20% compared with the traditional Mg-MOF-74 prepared with Mg(NO3)2·6H2O, which led to mesopores accounting for 36.9%, and the width of mesopores reached 13.1 nm. Compared with traditional Mg-MOF-74, the adsorption heat of CO2 at zero load of the defect-rich hierarchical porous Mg-MOF-74 increased from 36 kJ·mol−1 to 46 kJ·mol−1, and the saturated adsorption capacity of CO2 under ambient pressure was improved by 15%. Interestingly, the IAST selective adsorption performance of CO2/N2 was increased by 20 times. Compared with the saturated adsorption capacity for traditional Mg-MOF-74, the equivalent adsorption capacity of hierarchical porous Mg-MOF-74 only needs 17 kPa, indicating that it is suitable for carbon capture operation in a real flue environment. Calculations of density functional theory (DFT) confirmed that the active site of the hierarchical porous Mg-MOF-74 has a lower adsorption energy with CO2 due to the presence of defects, which is regarded to play a key role in improving the CO2 capture performance.

Study on heat transfer performance using ceramic membrane to recover moisture and waste heat from flue gas

The release of industrial flue gas into the environment leads to a significant waste of latent heat and water resources. To address this issue, the transmission membrane condenser (TMC) has emerged as a promising technology. However, research on TMC is still in its early stages, lacking performance evaluation of heat exchangers and analysis of heat and mass coupling effects. This paper presents experiments conducted to assess the heat transfer performance of TMC at different undercooling degrees and flue gas velocities. A comparison between TMC and 316L stainless steel pipe is made to identify the impact factors of heat and mass coupling effects in TMC. The study also derives a Nusselt formula suitable for single-channel ceramic membranes, providing theoretical guidance for their application.

Predicting solvent degradation in absorption–based CO2 capture from industrial flue gases

This work aims to predict solvent degradation rates in absorption-based CO2 capture processes using a 30 wt% aqueous monoethanolamine (MEA) solvent. A degradation model for MEA is developed and used to predict solvent degradation in full-scale capture processes. Mass transfer resistances and the solubility of O2 are considered to obtain a generalized and consistent degradation model. Degradation is evaluated for the capture process for flue gases with typical industrial compositions; a natural gas-fired power plant, a waste-to-energy plant, a coal-fired– power plant, and a cement plant. The impact of process modifications, such as absorber intercooling, dissolved O2 removal, a reduction in solvent residence times, and increased stripper pressures on degradation is evaluated.The predicted degradation rate in the capture processes is approximately 90 to 150 g MEA/ton CO2 captured, and the composition of the flue gas was found to have a significant influence on the distribution of degradation throughout the process. Modifications to the process can significantly affect the overall degradation rate. Both absorber intercooling and removal of dissolved O2 may reduce the overall degradation by up to 40%, depending on the composition of the flue gas. A reduction in solvent residence times or pressure in the stripper has limited effects on the degradation in the case of MEA, because of the amine’s relatively low stability towards oxidative degradation. However, these process modifications look promising for more stable solvents.

A prospective approach to separate industrial carbon dioxide and flue gases

ABSTRACT As the industrial revolution progresses, carbon dioxide (CO2) and sulfur dioxide (SO2) are major concerns because they are the main contributors to greenhouse gases. The concentration of these harmful gases in the industry is very high, which is emitted by workers and industrial materials. Therefore, it is required to maintain a safe percentage of CO2, SO2, and other harmful gases in the air of industry and ensure safety from fire accidents. This paper presents a compressor driven system that could capture harmful gases including CO2 and SO2 from the polluted air of different industries and households. The captured and separated CO2 works as a fire extinguishing agent to safeguard fire accidents for large industries and households. Thus, this system ensures a protected working place and a healthy atmosphere for industrial workers. Besides, this system can be applied in place of the exhaust gas recirculation (EGR) system in small industries and for a four-wheeler, internal combustion engine, as this system could capture and separate the harmful carbon dioxide and sulfur dioxide. This paper also presents a developed model of different polymeric membranes to simulate the separation of carbon dioxide after the post-combustion process. Computational Fluid Dynamics (CFD) has been performed by COMSOL 5.5 to observe the carbon dioxide separation by polymeric membranes like polycarbonate (0.07 mol/m3) and polytetrafluoroethylene (0.1 mol/m3) polymeric membranes for specific pore sizes which is comparable to experimental data (0.05 mol/m3).

Step-wise SO2-feeding strategies for microalgae-based CO2 fixation from flue gas and bioenergy production

Aiming at eliminating the negative effect of SO2 on microalgae CO2 fixation caused by inappropriate SO2-feeding strategies, physiology-based step-wise SO2-feeding strategies were proposed to enhance the bioenergy production of microalgae. The step-wise SO2-feeding strategy (four-step gradient increase from 100 to 400 ppm followed by four-step gradient decrease from 400 to 100 ppm) successfully realized the gratifying proliferation of microalgae by maintaining a better activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), total adenosine triphosphatase (Total ATPase), superoxide dismutase (SOD), and catalase (CAT) enzyme. Moreover, the step-wise SO2-feeding strategy, which considered the microalgal tolerance to sulfur at different growth stages, reduced the accumulation rate of toxic S-compounds in the culture medium by 47.2% and ensured a favorable solution pH of around 7 without the addition of alkaline chemical reagents. Sulfur replenishment and utilization were well-matched (SO2 → HSO3-+SO32-→SO42-→intracellular ammonia acid) under a step-wise SO2-feeding strategy, contributing to a maximum microalgal biomass concentration of 3.26 g L-1, a photosynthetic efficiency of 10.89 %, and biomass energy of 18.97 kJ, which was 85.2%, 185%, and 390% higher than the microalgae cells cultivated under 300 ppm SO2, respectively. Moreover, an increment of 81.4% in CO2 utilization efficiency was also achieved. Overall, this study provided an effective method for achieving microalgal carbon capture from industrial flue gas with high SO2 concentrations.

Catalytic Oxidation Activity of NO over Mullite-Supported Amorphous Manganese Oxide Catalyst.

Nitric oxide (NO) can pose a severe threat to human health and the environment. Many catalytic materials that contain noble metals can oxidize NO into NO2. Therefore, the development of a low-cost, earth-abundant, and high-performance catalytic material is essential for NO removal. In this study, mullite whiskers on a micro-scale spherical aggregate support were obtained from high-alumina coal fly ash using an acid-alkali combined extraction method. Microspherical aggregates and Mn(NO3)2 were used as the catalyst support and the precursor, respectively. A mullite-supported amorphous manganese oxide (MSAMO) catalyst was prepared by impregnation and calcination at low temperatures, in which amorphous MnOx is evenly dispersed on the surface and inside of aggregated microsphere support. The MSAMO catalyst, with a hierarchical porous structure, exhibits high catalytic performance for the oxidation of NO. The MSAMO catalyst, with a 5 wt% MnOx loading, presented satisfactory NO catalytic oxidation activity at 250 °C, with an NO conversion rate as high as 88%. Manganese exists in a mixed-valence state in amorphous MnOx, and Mn4+ provides the main active sites. The lattice oxygen and chemisorbed oxygen in amorphous MnOx participate in the catalytic oxidation of NO into NO2. This study provides insights into the effectiveness of catalytic NO removal in practical industrial coal-fired boiler flue gas. The development of high-performance MSAMO catalysts represents an important step towards the production of low-cost, earth-abundant, and easily synthesized catalytic oxidation materials.

Development of an integrated membrane condenser system with LNG cold energy for water recovery from humid flue gases in power plants

This paper investigates a detailed thermodynamic analysis of a modular-type membrane condenser system where a cooler or condenser is connected in series upstream of the membrane condenser module. A coolant circulates inside the cooler/condenser to cool down the industrial flue gas up to saturation conditions. The analysis covers water recovery rate and energy requirement for different combinations of flue gas humidity, flow rate, and temperature. Additionally, a case study is included which considers a practical industrial exhaust flue gas where the constituents of the flue gas with volumetric ratio and the feed parameters are referred from the literature. The case study investigated the utilization of cold energy obtained by LNG regasification facility as a cooling power source for the water vapor recovery process. A detailed heat transfer analysis based on the heat exchanger model is performed to determine the required mass flow rate of cooling water and natural gas. It is concluded that, the water self-sufficiency of a power plant can be achieved if the mass flow rate of the −50 °C natural gas which is entering the membrane condenser is kept around 0.3 kg s−1 for every 1 kg s−1 flow rate of the 168 °C flue gas.

A model for assessing pathways to integrate intermittent renewable energy for e-methanol production

Renewable methanol has potential to be a key vector for attaining net zero emissions by providing a pathway to carbon neutrality for the value chains of carbon intensive industries with hard to abate emissions. To deliver an accurate assessment of feasibility, it is critical to understand the integrated operation and economies of the connected generation and conversion technologies that make up Power-to-Methanol (PtM) pathways. Given the highly variable nature of renewable energy (RE) and green hydrogen generation, it is also important to consider the need for feedstock and energy buffers to achieve reliable operation. Herein, we developed a globally applicable open-source cost framework consisting of a farm-to-gate model of Power-to-Methanol (PtM) populated with performance and cost functions from process simulation, recent literature, and industry consultation. This open-source tool was developed to evaluate PtM projects at various scales and locations, utilizing different recycled carbon feedstock sources, with a range of renewable power generation and electrolyser configurations, as well as balancing technologies including intermediate feedstock and power storage options. A key feature of the tool is the ability to analyse and optimize the incorporation of these balancing technologies. By using present cost estimates and defining design constraints to maintain operational viability, we apply this framework to map out the economies of PtM for potentially suitable Australian and international locations as case studies. The study estimates indicative levelized cost of methanol (LCMeOH) of 1360 A$/tMeOH and 1710 A$/tMeOH corresponding to PtM including CO2 sourced from industrial flue gas (IFG) and direct air capture (DAC) respectively. While the case studies analysed in this work consist mainly of Australian locations, the open-source tool is applicable for other global locations as demonstrated by the cases evaluated for PtM in Chile and Germany. The tool presented here aims to serve as a customisable framework to support the assessment, optimization, and deployment of commercial scale e-methanol projects.

Under-coordinated selenide enriched amorphous cobalt selenide prepared under ambient conditions for highly efficient immobilization of gaseous elemental mercury

The limited adsorption capacity of commercialized sorbents towards elemental mercury (Hg0) remains a major challenge facing their extensive applications under the regulation of the Minamata Convention. Metal selenides were recently found to be promising alternatives to commercialized sorbents for capturing Hg0 from industrial flue gas due to the high affinity between Hg0 and selenide. In metal selenides, under-coordinated selenide sites play critical roles in oxidation and subsequent immobilization of Hg0, while there is still no simple way to increase the abundance of under-coordinated selenide in metal selenides under ambient conditions. In this work, an effective and facile precipitation pathway was proposed to prepare amorphous cobalt selenide (a-CoSe2) with under-coordinated selenide enriched surface under ambient conditions. The a-CoSe2 as synthesized achieved outstanding Hg0 uptake capacity and adsorption rate (534.2 mg g−1 and 483.1 μg g−1 min−1), far surpassing those of crystalline cobalt selenide (c-CoSe2) by magnitudes. The characteristic results demonstrated that the under-coordinated selenide enriched nature of a-CoSe2 is the principal reason causing the significant performance improvement, which is fully in line with our hypothesis and purpose. This work not only proposes a potential sorbent for efficient Hg0 sequestration from industrial flue gas but also inspires the further development of synthesis strategies for amorphous materials.

Physiological and molecular insights into adaptive evolution of the marine model diatom Phaeodactylum tricornutum under low-pH stress

The direct use of industrial flue gas in microalgae production is desired for mitigating CO2 emissions, but the low pH resulting from the inflow of acidic gases (mainly CO2, NOx, and SOx) imposes detrimental effects on microalgal growth and is considered the main technical challenge for simultaneous biomass production and CO2 sequestration. In this study, we investigated the adaptive responses of the model marine diatom Phaeodactylum tricornutum to acidic stress at pH 6.0. Gradual changes in the ratio of morphotypes, chlorophyll content, and photosynthetic efficiency were observed as a result of adaptive laboratory evolution (ALE) under constant acidic stress. The evolved strains showed a significant increase in growth rate in acidic conditions after ALE, and phenotypic characterization demonstrated a stable trait of acid tolerance with an average increase in growth by 110.4%, 46.1%, and 27.5% at pH 5.5, 6.0, and 6.5, respectively compared with the parental wild-type strain. Furthermore, RNA sequencing and whole-genome re-sequencing analyses revealed that core pathways, including photosynthesis, pH regulation/ion transport, and carbohydrate and fatty acid metabolism, were upregulated across all three evolved strains, though they exhibited different evolutionary trajectories. This study demonstrated the feasibility of recovering photosynthetic capability after acidic stress in the marine diatom P. tricornutum through ALE and provided molecular data to reveal essential alterations in genetic regulations that could enable cells to tolerate low environmental pH.

Ultra-superhydrophobic MOFs coated on polydopamine-modified polyethylene terephthalate for efficient removal of particulate matter

To achieve ultra-low emissions in industrial flue gas, three different micro/nano metal–organic-framework (MOF) crystals (NH2-MIL-125, ZIF-8 and HKUST-1), as active purification units, were assembled on polydopamine (PoDA)-modified PET fibers (p-PET) by rapid, efficient, and supramolecular self-polymerization at room temperature to construct a novel superhydrophobic composite filter material (SH-Mp-PET(Ti, Zn, Cu)). The wrinkle structure and dielectric constant on the surface of SH-Mp-PET(Ti, Zn, Cu) filter fiber were improved by the synergistic effect of PoDA and MOF, and the charge effect on the surface of the three composite filter materials was improved, so that the electrostatic interaction between the fiber and the particles was improved. At the same time, the porous structure within the MOF did not result in significant pressure loss, and the purification quality factor (QF) of ultra-fine PM was significantly improved by the dual modification of RE and ΔP. The QF of three SH-Mp-PET(Ti, Zn, Cu) filter media were 22.9 %, 29.6 % and 28.1 % higher than PET, respectively. And SH-Mp-PET exhibited good thermal and mechanical stability. This approach can promote the development of industrials flue gas superhydrophobic filter materials and provides a new concept for developing MOF materials for flue gas treatment and reuse.

Exergoeconomic performance evaluation of three, four, and five-step thermochemical copper-chlorine cycles for hydrogen production

Thermochemical water-splitting processes are among the most promising options for producing sustainable and green hydrogen due to being extremely environmentally benign. Being extensively investigated in the literature, the thermochemical copper-chlorine cycle has demonstrated much promise in this regard as one of the most efficient options for thermochemically obtaining hydrogen. Thus, this study focuses on investigating the exergoeconomic performances of the different variants of the copper-chlorine cycle including the three-, four-, and five-step versions. All cycles are modeled and simulated in Aspen-plus software by considering a recovery of thermal energy from industrial waste flue gases in addition to internal heat recovery. Moreover, a hydrogen production capacity of 668 kg/h is considered for all cycles. The Specific Exergy Costing methodology is employed to study the exergoeconomic performance of each cycle. All cycles are initially examined in terms of the cost rates of energy transfer and hourly levelized cost rates for each step. The cycle variants are further examined through a comparative assessment of several performance parameters including hydrogen cost rates, overall cost rates of energy transfer, and overall hourly levelized cost rates. According to the performed analyses, the three-step variant of the cycle that constitutes a high-temperature electrolysis process produces hydrogen at the lowest cost rate (0.83 $/kg) while the four-step cycle produces hydrogen at the highest cost rate (1.82 $/kg). Furthermore, the hydrolysis step is found to have the highest hourly levelized cost rates for all variants of the cycle. Several factors that impact the hydrogen cost rate are also examined comprehensively. In addition, the extent to which the hydrogen cost rate is sensitive to those factors is discussed.

Microalga–bacteria Community with High Level Carbon Dioxide Acclimation and Nitrogen-fixing Ability

Microalgal conversion of high-level CO2 in industrial flue gas to value-added products is attractive technology for mitigating global warming. However, reduction of microalgal production costs for medium ingredients, particularly nitrogen salts, is essential. The use of atmospheric nitrogen as a nitrogen source for microalgal cultivation will dramatically reduce its production costs. We attempted to enrich a microalga-bacteria community, which fixes both CO2 and atmospheric nitrogen under high level CO2. By cultivating biofilm recovered from the surface of cobbles in a riverbank, a microalgal flora which grows in a nitrogen salts-free medium under 10% CO2 was enriched, and the coccoid microalgal strain MP5 was isolated from it. Phylogenetic analysis revealed that the strain MP5 belongs to the genus Coelastrella, and the closest known species was C. terrestris. With PCR-DGGE analysis, it was found that the enriched microalgal community includes bacteria, some of which are suggested diazotrophs. The addition of bactericides in culture medium inhibited MP5 growth, even though the strain MP5 is eukaryotic. Growth of bacteria-free MP5 was stimulated by addition of Agrobacterium sp. isolates in nitrogen salts-free medium, suggesting that MP5 and the bacteria have responsibility for photosynthetic carbon fixation and nitrogen fixation, respectively.

Functional metabolism pathways of significantly regulated genes in Nannochloropsis oceanica with various nitrogen/phosphorus nutrients for CO2 fixation

To determine the optimal CO2 concentration for microalgal biomass cultivated with industrial flue gas and improve carbon fixation capacity and biomass production. Functional metabolism pathways of significantly regulated genes in Nannochloropsis oceanica (N. oceanica) with various nitrogen/phosphorus (N/P) nutrients for CO2 fixation were comprehensively clarified. At 100 % N/P nutrients, the optimum CO2 concentration was 70 % and the maximum biomass production of microalgae was 1.57 g/L. The optimum CO2 concentration was 50 % for N or P deficiency and 30 % for both N and P deficiency. The optimal combination of CO2 concentration and N/P nutrients caused significant up regulation of proteins related to photosynthesis and cellular respiration in the microalgae, enhancing photosynthetic electron transfer efficiency and carbon metabolism. Microalgal cells with P deficiency and optimal CO2 concentration expressed many phosphate transporter proteins to enhance P metabolism and N metabolism to maintain a high carbon fixation capacity. However, inappropriate combination of N/P nutrients and CO2 concentrations caused more errors in DNA replication and protein synthesis, generating more lysosomes and phagosomes. This inhibited carbon fixation and biomass production in the microalgae with increased cell apoptosis.

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.