CO2 Adsorption Performance Research Articles

Enhancement of CO2 adsorption performance and widening of adsorption temperature window by co-doping different valence state metals on the Li4SiO4 (010) surface

Lithium silicate (Li4SiO4) has good stability, high theoretical carbon dioxide (CO2) adsorption capacity, and low regeneration temperature. It has great potential in the field of CO2 adsorption. However, it is difficult to achieve the theoretical value in practical applications and a narrow temperature window for adsorption. Therefore, further research in this area is urgently needed. In this study, experimental and simulation methods were used to investigate the effects of single doping and co-doping with K, Na, Be, Ca, and Al metals on the adsorption performance and adsorption temperature window of Li4SiO4. Single doping with K, Na, or Al makes CO2 easier to be adsorbed on the Li4SiO4 (010) surface by increasing the charge transfer from the Li4SiO4 surface to CO2. Co-doping with K and Al increases the adsorption energy of CO2 on the Li4SiO4 (010) surface, enhances hybrid peaks, and broadens the temperature range for CO2 adsorption on the Li4SiO4 surface. It exhibits stable cyclic adsorption performance under low CO2 (15% CO2, N2 balance) concentration, and more electron transfer facilitates the formation of carbonate species on the Li4SiO4 (010) surface at lower temperatures, thereby improving its CO2 adsorption performance.

Synthesis, characterization, and CO2 adsorption performance of UiO-66-(OH)2/GO composite

The flue gas produced by fossil fuel combustion contains a large amount of CO2, and the greenhouse effect caused by CO2 emissions is becoming increasingly serious. There is an urgent need to develop adsorbents with excellent CO2 adsorption performance. In this study, a new composite graphene oxide (GO) -metal-organic framework (MOF) (UiO-66-(OH)2/GO) was synthesized using UiO-66-(OH)2 as a precursor. Structural analysis of the parent materials and composites found that pore structures and Brunauer–Emmett–Teller (BET) surface area could be adjusted by adding GO, and GO was tested as a carbon dioxide adsorbent at 273 K and 298 K. The maximum CO2 adsorption of the composites was 5.03 mmol/g and 4.34 mmol/g, which was 36.7% and 36.9% higher than that of the parent materials at 1 bar, respectively. Dynamic breakthrough experiments were used to study the CO2/N2 separation capability of the composites. The stability of composites was studied by chemical stability experiments and several adsorption/desorption experiments. The results showed that the composites had good acid resistance and cycle stability. The separation performance of CO2/N2 in the presence of water vapor was investigated, and the composites showed good water stability. Therefore, UiO-66-(OH)2/GO has latent applications in CO2 capture technology to mitigate global warming.

Enhancing CO2 adsorption performance of porous nitrogen-doped carbon materials derived from ZIFs: Insights into pore structure and surface chemistry

In this work, a novel approach for the synthesis of porous nitrogen-doped carbon materials (PNCs) with a highly microporous structure through low-temperature carbonization of ZIF-8 and ZIF-61 assisted by KCl and NaCl is reported. The introduction of KCl and NaCl during the carbonization process can adjust the surface chemical properties and pore structures of the PNCs derived from ZIF-8 and ZIF-61. The effects of pore structures and surface groups of PNCs on CO2 adsorption capacity are explored. Results show that the cumulative pore volume in the pore size range of 5–7 Å (V5-7 Å), pyrrolic-N content, and COOH content exert favorable influences on CO2 adsorption capacity at 1 bar and 25 °C. Notably, V5-7 Å is the key factor in enhancing the CO2 adsorption capacity of PNCs. Moreover, the degree of contribution of V5-7 Å, V7-9 Å, pyrrolic-N content, pyridinic-N content, and COOH content to the CO2 adsorption capacity is evaluated by establishing a multiple linear regression equation, and the results show that on the basis of PNCs possessing optimum pore structures (V5-7 Å > 0.10 cm3/g), pyrrolic-N content in PNCs becoming the dominant contributor to CO2 adsorption capacity. The as-prepared 2CN8-KCl-600 sample demonstrates high CO2 adsorption capacity, which reaches 4.61 mmol/g at 25 °C and 6.70 mmol/g at 0 °C (1 bar), respectively. Besides, 2CN8-KCl-600 exhibits high CO2/N2 selectivity (39.5) under the typical flue gas scenario and high cycling stability. This work offers a novel perspective on preparing highly efficient carbon-based adsorbents for CO2 and provides the fundamental understanding for enhanced CO2 adsorption performance on PNCs.

Porous hollow CaO microsphere synthesized by the template-assisted approach for enhanced CO2 capture

The development of cheap, environmentally friendly adsorbents with high adsorption capacity and good cycle stability is of great significance for reducing excessive CO2 emissions. However, the CaO-based adsorbents with low prices and high theoretical adsorption capacity suffer from serious sintering problems and poor cyclic stability. Herein, we synthesized porous hollow CaO microspheres for enhanced CO2 capture by the template-assisted approach, in which the carbon sphere template with different carbon chain lengths were prepared by hydrothermal method. The interaction between carbon chain lengths, morphologies, and properties of CaO-based adsorbents was systematically investigated. The results show that the porous hollow CaO microsphere prepared with a sucrose carbon template possesses a higher initial CO2 adsorption capacity (15.3 mmol g−1) and better cyclic stability after 20 cycles by reducing the mass transfer length of CO2 and buffering the volume expansion. In addition, the kinetics study reveals that the porous hollow spherical morphology can significantly improve the CO2 adsorption kinetics, especially in the chemical control stage, which provides theoretical guidance for the further understanding of the carbonization process. The systematic study marks the significance of precise tailoring of porous hollow CaO microsphere to achieve the desired performance of CO2 adsorption.

N-rich chitosan-derived porous carbon materials for efficient CO2 adsorption and gas separation.

Capturing and separating carbon dioxide, particularly using porous carbon adsorption separation technology, has received considerable research attention due to its advantages such as low cost and ease of regeneration. In this study, we successfully developed a one-step carbonization activation method using freeze-thaw pre-mix treatment to prepare high-nitrogen-content microporous nitrogen-doped carbon materials. These materials hold promise for capturing and separating CO2 from complex gas mixtures, such as biogas. The nitrogen content of the prepared carbon adsorbents reaches as high as 13.08wt%, and they exhibit excellent CO2 adsorption performance under standard conditions (1 bar, 273K/298K), achieving 6.97mmol/g and 3.77mmol/g, respectively. Furthermore, according to Ideal Adsorption Solution Theory (IAST) analysis, these materials demonstrate material selectivity for CO2/CH4 (10 v:90 v) and CO2/CH4 (50 v:50 v) of 33.3 and 21.8, respectively, at 1 bar and 298K. This study provides a promising CO2 adsorption and separation adsorbent that can be used in the efficient purification process for carbon dioxide, potentially reducing greenhouse gas emissions in industrial and energy production, thus offering robust support for addressing climate change and achieving more environmentally friendly energy production and carbon capture goals.

Fluidity comparison of biomass-derived activated carbon and TiO(OH)2 and its improving toward promoted low-temperature CO2 capture in gaseous medium

Biowaste-derived activated carbons (ACs) and TiO(OH)2 are considered promising materials for effective CO2 capture. TiO(OH)2 has not been employed in gas phase adsorption process; moreover, the comparison of fluidization of these materials had not been investigated. Hence, this study not only did evaluate the CO2 adsorption performance of both synthetic TiO(OH)2 and biomass-derived AC, but also assessed their fluidity aimed to implement at pilot scales. The samples were examined using XRD, BET, SEM, EDX, FTIR, and TGA techniques. The adsorption of the adsorbents was evaluated through TGA under several conditions. The AC demonstrated an average CO2 capture capacity of 3.54 mmol/g, surpassing that of the TiO(OH)2 (0.971 mmol/g) during three successive cycles at 25/120 ℃ under a CO2/N2 flow of 90/10 vol% and 1 bar. Adding 5 wt% of auxiliary SiO2 nanoparticles enhanced bed expansion of AC and TiO(OH)2 by 1.83 and 1.5 times respectively, due to dwindling interparticle cohesive interactions.

A Data-Driven Approach to Molten Salt Synthesis of N-Rich Carbon Adsorbents for Selective CO2 Capture.

Applying a design of experiments methodology to the molten salt synthesis of nanoporous carbons enables inverse design and optimization of nitrogen (N)-rich carbon adsorbents with excellent CO2 /N2 selectivity and appreciable CO2 capacity for carbon capture via swing adsorption from dilute gas mixtures such as natural gas combined cycle flue gas. This data-driven study reveals fundamental structure-function relationships between the synthesis conditions, physicochemical properties, and achievable selective adsorption performance of N-rich nanoporous carbons derived from molten salt synthesis for CO2 capture. Taking advantage of size-sieving separation of CO2 (3.30 Å) from N2 (3.64 Å) within the turbostratic nanostructure of these N-rich carbons, while limiting deleterious N2 adsorption in a weaker adsorption site that harms selectivity, enables a large CO2 capacity (0.73mmol g-1 at 30.4Torr and 30 °C) with noteworthy concurrent CO2 /N2 selectivity as predicted by the ideal adsorbed solution theory(SIAST = 246) with an adsorbed phase purity of 91% from a simulated gas stream containing only 4% CO2 . Optimized N-rich porous carbons, with good physicochemical stability, low cost, and moderate regeneration energy, can achieve performance for selective CO2 adsorption that competes with other classes of advanced porous materials such as chemisorbing zeolites and functionalized metal-organic frameworks.

Amine-enriched Ti/SiOx framework fabricated via one-step photochemical synthesis for carbon dioxide adsorption and separation applications

The coordination environment encompassing the amine sites governs the stability of the adsorbent. In this work, an amine-enriched Ti/SiOx framework (OP-ATSO) was constructed through a one-step hydrolytic polymerization induced under ultraviolet irradiation in order to increase the amine content. Characterization results as well as CO2 adsorption and separation performance evaluation show that compared with the amine-functionalized Ti/SiOx (HT-ATSO) synthesized through conventional hydrothermal means followed by post-synthetic impregnation, OP-ATSO possesses more abundant amine sites on the framework, which in turn exhibits enhanced CO2 adsorption capacity, two-fold increase in CO2/N2 separation coefficient, and outstanding cyclic adsorption stability. The one-step photochemical synthesis procedure dramatically reduces the time and operating steps of material synthesis, concurrently eliminating liquid waste. This work provides a novel concept of developing superior sorbents with high CO2 adsorption performance.

Based on machine learning model for prediction of CO2 adsorption of synthetic zeolite in two-step solid waste treatment

The rising environmental issues caused by carbon dioxide emissions and accumulation of industrial solid waste accelerate the development of carbon capture utilization and storage (CCUS), especially the technology using industrial solid waste as a raw material to prepare environmentally friendly and sustainable porous materials to capture CO2. This study developed four models including support vector regression(SVR), multivariate adaptive regression spline(Mars), random forest(RF), and gradient boosting machine(GBM) based on 762 CO2 adsorption datasets of zeolites synthesized from five different industrial solid waste materials to predict the CO2 adsorption capacity and analyze impact of various factors on CO2 adsorption performance during synthesis and adsorption processes. The results suggested that gradient boosting machine(GBM) and the support vector regression(SVR) have good accuracy and generalization performance. The R2 of the model reached 0.99 and 0.96 respectively, which is in good agreement with the laboratory data. In general, the specific surface area(S) and adsorption pressure(P) during the adsorption process of zeolite have a great influence on the final adsorption performance. The correlation between the specific surface area(S) and the hydrothermal reaction temperature(T2) is the largest, and its Pearson Correlation Coefficient is 0.61. This study paved a new approach for the accumulation treatment of industrial solid waste and low-carbon industry via statistical analysis and machine learning method, which is beneficial to environmental protection and sustainable development.

Unlocking the potential of N-doped porous Carbon: Facile synthesis and superior CO2 adsorption performance

Porous carbon derived from bio-based sources is highly regarded as a promising adsorbent material, attributed to its exceptional CO2 uptake performance and favorable CO2/N2 selectivity. In this study, we employed a one-step chemical activating technique to fabricate self-heteroatom-doped porous carbon utilizing chitosan as a carbon precursor and KOH as chemical activating reagent. Subsequent activation processes resulted in the porous carbons possessing an excess amount of nitrogen functionality and advanced textural feature. Remarkably, a high CO2 capture amount of 4.40 mmol/g was accomplished at 25 °C and 1 bar, accompanied by a significant CO2/N2 selectivity of 21 for the dual gas blend. The gas adsorption mechanisms were thoroughly discussed, elucidating the factors contributing to the exceptional performance. The superior adsorption and separation capabilities, enhanced recyclability and effective dynamic adsorption capability, establish this N-enriched carbon as a potential adsorbent for CO2 uptake. The present work presents a novel approach for designing high-performance carbon-based CO2 adsorbents.

Effective adsorptive removal of trace CO2 from olefin using alkanolamine‐polyethylenimine‐functionalized fumed silica

AbstractThe purification of gaseous olefins, such as C2H4 and C3H6, requires the efficient removal of trace CO2 impurities. However, the development of ideal adsorbents with high CO2/olefin selectivity has remained a challenge. In this study, we synthesized a novel adsorbent, denoted as PEI/DEA@FS, by modifying fumed silica (FS) with a combination of polyethylenimine (PEI) and diethanolamine (DEA). At 298 K and 0.0004 bar, PEI/DEA@FS presented the highest CO2 adsorption capacity among previously studied adsorbents, with a value of 2.12 mmol/g. Notably, PEI/DEA@FS demonstrated very high ideal adsorption solution theory selectivity for CO2/C2H4 (>1010) and CO2/C3H6 (>107) at 298 K and 0.01 bar. Breakthrough experiments revealed its excellent separation performance, producing olefins (C2H4 and C3H6) with ultra‐high purity (>99.9%) from a CO2/olefin (1/99) mixture. Moreover, PEI/DEA@FS exhibited outstanding stability over 20 adsorption and desorption cycles, and its CO2 adsorption performance remained almost unchanged under 75% relative humidity in the feed stream.

Heteroatom-doped biochar devised from cellulose for CO2 adsorption: a new vision on competitive behavior and interactions of N and S

Biochar, as a potential CO2 adsorbent, is of great significance in addressing the problem of global warming. Previous studies have demonstrated that the CO2 adsorption performance of biochar can be improved by nitrogen and sulfur doping. Co-doping can integrate the structure and function of two elements. However, the physicochemical interaction of nitrogen and sulfur during doping and the CO2 adsorption process remains unclear in co-doped biochar. In this study, the heteroatom-doped biochar was prepared with different additives (urea, sodium thiosulfate, and thiourea) via hydrothermal carbonization, and the physicochemical interaction of nitrogen and sulfur in co-doped biochar was investigated extensively. The findings revealed that nitrogen and sulfur competed for limited doped active sites on the carbon skeleton during the co-doping process. Interestingly, thiourea retained the amino group on the surface of biochar to a great extent due to carbon–sulfur double bond breaking and bonding, which facilitated the formation of pore in the activation process. Significantly, co-doping had no significant improvement effect although nitrogen and sulfur doping separately enhanced the CO2 adsorption performance of biochar by 11.9% and 8.5%. The nitrogen-containing and sulfur-containing functional groups in co-doped biochar exhibited mutual inhibition in the process of CO2 adsorption. The findings of this study will have pertinent implications in the application of N/S co-doped biochar for CO2 adsorption.Graphical

Direct air CO2 capture using coal fly ash derived SBA-15 supported polyethylenimine

Designing an amine modified silica derived from coal fly ash (CFA) towards direct air CO2 capture (DAC) provides an economic way to manage increasing atmospheric CO2 concentration utilizing solid wastes. In this work, rod-like SBA-15 (SBA-15-R) and wheat-like SBA-15 (SBA-15-W) with distinct pore lengths are synthesized from CFA by controlling the synthesis conditions and then modified by PEI via the wet impregnation method. Their CO2 adsorption behaviors under sub-ambient conditions are investigated to explore their feasibility under aggressive conditions. The adsorbents with various silica morphologies exhibit distinctive CO2 adsorption performance under ambient and sub-ambient conditions. At 35°C under dry conditions, the CO2 adsorption capacity increases with amine loading. The CO2 adsorption capacity (qe) of SBA-15-W-PEI with long channels reaches the highest qe of 1.92 mmol/g with 70 wt.% PEI loading due to a large amount of strong chemisorption sites. Under the sub-ambient conditions (-20°C, 400 ppm), SBA-15-R-PEI30 with short channels having weaker CO2 diffusion resistance exhibits promising CO2 uptake of 0.83 mmol/g. These findings indicate that the ultra-dilute CO2 adsorption at ambient temperature requires an adsorbent with large amounts of adsorption sites, whereas the adsorbents for cold temperature application should reconcile amine loading with CO2 diffusion resistance inside pores. The co-adsorption of H2O and CO2 significantly improves CO2 capacity from 0.83 mmol/g and 1.92 mmol/g to 1.81 mmol/g and 3.48 mmol/g for SBA-15-R-PEI30 (-20°C, 400 ppm) and SBA-15-W-PEI70 (35°C, 400 ppm), respectively. Furthermore, the CFA derived SBA-15-PEI shows good cyclic stability during five consecutive TSA cycles. Preparing the amine silica adsorbents from coal fly ash potentially reduces the adsorbent cost of DAC devices. Moreover, the systematic exploration of amine silica adsorbents at a wide range of temperatures guides the design of high-performance CO2 adsorbents employed under various climatic conditions.

Scalable production of wood carbon microspheres for high-efficiency carbon dioxide capture

Utilizing abundantly available biomass materials to prepare adsorbent substances is a simple and cost-effective method for CO2 adsorption, which, however, is often hampered by low adsorption capacity. Here, we demonstrate near-spherical active carbon (C-DWP/Zn) with high CO2 adsorption ability, employing delignification combination with ZnCl2 activation of natural wood powder. Removing lignin from wood cell walls facilitates easy absorption of Zn ions by the cellulose nanofibers (CNFs), thereby promoting micro/nano pores formation. Moreover, rapid dehydration of cellulose molecular chains alters the morphology of activated carbon, resulting in a transition from a granular to a near-spherical shape. Consequently, C-DWP/Zn with high specific surface area of 1769 m2 g−1, shows a significantly higher microporous volume than that of a control sample without delignification. The CO2 adsorption capacity of C-DWP/Zn, with values of 3.51 mmol g−1 and 5.12 mmol g−1 at 1 bar, 25 °C and 0 °C, respectively, is superior to that of commercial activated carbon. Attributable to its optimal micropore structure, C-DWP/Zn exhibits high CO2/N2 selectivity. Furthermore, the high carbon dioxide adsorption efficiency of C-DWP/Zn was maintained and the substance could be reused at least 20 times. Near-spherical active carbon adsorbents prepared from low-value wood powders, all featuring high CO2 adsorption performances, reasonable CO2/N2 selectivity, good recoverability, suitable heat of adsorption, and fast adsorption kinetics, which are promising candidates for practical CO2 adsorption.

In-situ implantation of oxygen-containing reaction site in heterogeneous carbon–nitrogen in-plane polymer heterojunction with donor–acceptor feature for enhanced CO2 photoconversion

Herein, a heterogeneous carbon–nitrogen heterojunction g-C3N4-C2N (CC) is constructed by embedding electrophilic hexaazatriphenylene (HAT) into the heptazine framework of graphitic carbon nitride (g-C3N4) through in-plane fusing. The similar chemical compositions and molecular structures between g-C3N4 and C2N derived from HAT allow for great compatibility in co-planarly grafting. Electrochemical tests and theoretical calculations show that after co-planar grafting with C2N, g-C3N4 forms a typical donor–acceptor relationship with it. The photoinduced electrons generated by the excitation of the composite would converge to C2N, effectively enhancing the separation of electron-hole pairs. Moreover, oxygen-doped g-C3N4-C2N (CC-O) is obtained by the introduction of oxygen-containing functional groups, and the CO2 adsorption performance is further optimized. In the absence of any co-catalyst, photosensitizer or organic sacrificial agent, the photocatalytic reduction of CO2 to CO on the oxygen-doped polymer CC-O0.2 exceeded a yield of 28.64 μmol g-1h−1 with a selectivity of 99 %. Furthermore, the reaction site for photoconversion and the reason for different photocatalytic efficiency are revealed. The strategy of synergizing the two modification methods in this work offers more possibilities for the rational design of organic polymers for light-driven carbon neutralization.

Influence of Gas Type on Adsorption Performance of Chabazite

Chabazite is a kind of aluminosilicate with special structure. In recent years, a large number of related studies have proved that it has good CO2 adsorption performance. In this paper, the effect of gas species on the adsorption capacity of chabazite at a certain temperature was studied, and the conclusion was drawn: under the temperature of 60℃, the adsorption capacity of chabazite for N2 was 1.0 mmol/g, and the adsorption capacity for CO2 was 2.4 mmol/g, there is a relatively large difference in the adsorption capacity of these two gases.

Enhanced CO2 adsorption performance by crystal defect method of multi-level pore Mg-MOF-74 using organic acids

Metal-organic frameworks (MOFs) are popular crystalline materials owing to their high porosity, tunable pore structure, and large surface area. By introducing a carboxylic acid to compete with 2,5-dihydroxyterephthalic acid for magnesium ions in solution, a crystal defect method was used to prepare multi-level pore Mg-MOF-74 with an unregular framework structure of Mg-MOF-74 in this paper. In the prepared samples, the adsorption amounts varied in descending order with various carboxylic acid species: Mg-MOF-74-Propionic acid (37.95 cm3/g STP) > Mg-MOF-74 (15.46 cm3/g STP) > Mg-MOF-74-Acetic acid (9.19 cm3/g STP) > Mg-MOF-74-Formic acid (7.81 cm3/g STP). At 1.5 kPa, the CO2 adsorption of 2,5-dihydroxyterephthalic acid and propionic acid with a ratio of 2:1 can reach 2.78 cm3/g STP (standard temperature and pressure) with the comparison to 0.47 cm3/g STP of pristine Mg-MOF-74. Under atmospheric pressure, the adsorption capacity of modified Mg-MOF-74 can reach 37.95 cm3/g STP, equivalent to 2.45 times of the original Mg-MOF-74.

Integrations of desulfurization, carbon capture, and methanation at an isothermal intermediate temperature

Integrated CO2 capture and conversion (iCCC) technology has been recognized as the most efficient technology for Carbon Capture, Utilization, and Storage (CCUS). However, its industrialization is hindered by some unsolved engineering problems. Typically, sulfur impurities in most industrial flue gas will have significant poisoning effects on the process. Herein, we report integrations of SO2 removal, CO2 capture and conversion (iSCCC) at an isothermal intermediate temperature in a two-fixed-bed column system. By rationally developing the SO2 adsorbent pellets of ZnO-CaO, the CO2 adsorbent pellets of AMS-MgO, and the methanation catalyst pellets of Ni-La/Al2O3, each individual unit is optimized. Specifically, the in-situ dynamic structure evolution observed by the atmospheric aberration-corrected scanning transmission electron microscopy as well as the theoretical dynamics calculation provide an in-depth understanding of the CO2 adsorption and desorption performance changing with the temperature on the AMS-MgO pellets, which builds a bridge for a successful 99.3 % CO2 methanation efficiency. As a result, the matched iSCCC process demonstrates exceptional performance from simulated flue gas containing 1000 ppm SO2 and 20 vol% CO2, with full desulfurization and decarbonation and a CO2 conversion efficiency of 93.6 % after 20 cycles isothermally at 400 °C, superior to all the reported performance so far as we know, providing a promising route to practical large-scale iSCCC towards carbon neutrality.

Tailored porous structure and CO2 adsorption capacity of Mg-MOF-74 via solvent polarity regulation

Metal-organic frameworks (MOFs) are promising materials for CO2 adsorption and capture. The unique crystal structure and the open porous structure of MOFs are key factors affecting their CO2 adsorption performance, but the precise tuning of MOF structures remains a challenge. Herein, we applied the Kamlet-Taft method to investigate the effect of solvent proton-supplying/accepting capaity (β/α parameters) on the structure and CO2 adsorption performance of Mg-MOF-74 by tuning the reaction solvent polarity. It was found that the ratio of the nucleation rate/growth rate of Mg-MOF-74 could be effectively controlled by adjusting the β/α value of the solvent, realizing the regulation of the crystal structure and morphology of Mg-MOF-74. In addition, the size of solvent molecules played a crucial role in the pore size of Mg-MOF-74. Interestingly, the solvent molecules were competitively coordinated with ligands and participate in the growth of Mg-MOF-74 upon decreasing the β/α value. The crystal structure, morphology and pore size of Mg-MOF-74 could be precisely regulated by the β/α value and molecular size of the reaction solvent, and the highest performing Mg-MOF-74 exhibited a CO2 adsorption capacity of 7.38 mmol/g.

Improved structure of Zr-BTC metal organic framework using NH2 to enhance CO2 adsorption performance

Modified mesoporous NH2-Zr-BTC mixed ligand MOF nanocomposites were synthesized via the hydrothermal method as a novel adsorbent for CO2 capture. The newly modified MOF-808 with NH2 demonstrated a similar mesoporous morphology as MOF-808, whereas the specific surface area, pore volume, and average particle size, respectively, increased by 15%, 6%, and 46% compared to those of MOF-808. The characterization analyses exhibited the formation of more active groups on the adsorbent surface after modification. In addition, a laboratory adsorption setup was used to evaluate the effect of temperature, pressure, and NH2 content on the CO2 adsorption capacity in the range of 25–65 °C, 1–9 bar, and 0–20 wt%, respectively. An increase in pressure and a decrease in temperature enhanced the adsorption capacity. The highest equilibrium adsorption capacity of 369.11 mg/g was achieved at 25 °C, 9 bar, and 20 wt% NH2. By adding 20 wt% NH2, the maximum adsorption capacity calculated by the Langmuir model increased by about 4% compared to that of pure MOF-808. Moreover, Ritchie second-order and Sips models were the best-fitted models to predict the kinetics and isotherm data of CO2 adsorption capacity with the high correlation coefficient (R2 > 0.99) and AARE% of less than 0.1. The ΔH°, ΔS°, and ΔG° values were − 17.360 kJ/mol, − 0.028 kJ/mol K, and − 8.975 kJ/mol, respectively, demonstrating a spontaneous, exothermic, and physical adsorption process. Furthermore, the capacity of MH-20% sample decreased from 279.05 to 257.56 mg/g after 15 cycles, verifying excellent stability of the prepared mix-ligand MOF sorbent.