CO2 Isotherms Research Articles

Tetrabutylphosphonium acetate and its eutectic mixtures with common-cation halides as solvents for carbon dioxide capture

The absorption and desorption isotherms of CO2 in the ionic liquid tetrabutylphosphonium acetate ([P4444][OAc]) were experimentally determined at 343.2 K in the pressure range 0–15 bar. Analysed in a mass basis, the CO2 absorption capacity of [P4444][OAc] is particularly competitive among that of phosphonium ionic liquids. A contribution of chemical absorption was evidenced from the shape of the isotherms, and a reaction scheme based on the abstraction of an acidic proton in the cation by the basic acetate anion, with a 1:2 (CO2 to ionic liquid) overall stoichiometry, was proposed. The investigation of the solid–liquid equilibria of the mixtures of [P4444][OAc] with its homologous halides, namely [P4444]Cl and [P4444]Br, led to the identification of eutectic behaviours, with the eutectic compositions having melting temperatures below 308.2 K, remarkably lower than the melting temperature of pure [P4444][OAc]. The CO2 absorption capacities of these eutectic compositions were then explored at 308.2 K, and also 343.2 K for comparative purposes. While advantageously allowing their utilisation as CO2-capturing solvents at lower temperatures, in comparison to pure [P4444][OAc] the eutectic mixtures did not lead to a major loss in CO2 absorption capacity, with greater physisorption compensating for the reduction in chemisorption.

Adsorption of carbon dioxide on MIL53(Al), CuBTC and K- NaX zeolite

CO2 adsorption on K exchanged NaX zeolites, and metal organic frameworks (MOFs), namely Cu-BTC and MIL53 (Al) was studied at 5 °C and 25 °C. Exchange via ultrasonic and traditional methods, was conducted at 50 °C and 70 °C. The maximum replacement of Na+ ion with K+ ion in the extra framework of zeolite was increased from 76% to 83% with increasing temperature from 50 °C to 70 °C in the ultrasonic method which is more effective than traditional one. Compared with the zeolites, the MOF adsorbents used in this work have higher Langmuir specific surface area values namely 1278, 1473 and about 1000 m2/g for MIL 53, Cu-BTC and zeolite adsorbents respectively. The resulting CO2 isotherms can be well represented by the Toth equation. Comparison of the isosteric heat of adsorption at zero loading shows that CO2 was adsorbed more weakly on MOFs than zeolites.

Mitigation of CO2 emissions by hydrotalcites of Mg3Al-CO3 at 0 °C and high pressure

This work shows the maximum CO2 capture capacity, using CO2 isotherms at 0, 20 and 30 °C and pressures of up to 35 atm, of four adsorbents with different particle size distribution and different pore size distribution: two hydrotalcites of Mg3Al-CO3, one synthesized in laboratory (C1) and another commercial (C2) and two calcined (C1 500 and C2 500) obtained from C1 and C2 by calcination at 500 °C for 2 h, respectively. The maximum capture capacities were obtained for samples calcined (CLDH), 98.16 mg·g−1 for C2 500 sample and 142.02 mg·g−1 for sample C1 500, both at 0 °C and 34.28 atm. The capture capacity of the C2 500 sample was the least influenced by temperature changes, which could be related to the porous structure of the samples. Consequently, for applications that are carried out between 0 and 30 °C, the best sample will be C2 500. Previously the samples were characterized by X-ray diffraction, transmission and scanning electron microscopy, thermogravimetric and thermo-differential analysis, particle size distribution and pore size distribution by N2 adsorption isotherms. The CO2 adsorption isotherms data were adjusted to the Freundlich, Langmuir, Dubinin-Radushkevich y Temkin models. These two last models confirmed that the nature for CO2 adsorption was physical. In short, this work showed the usefulness of calcined hydrotalcite as a CO2 adsorbent, using low temperature (0 °C) and high pressure (34.28 atm) as working conditions.

Selective adsorption of CO2 by Hex-star phosphorene from natural gas: Combining molecular simulation and real adsorbed solution theory

The performances of multilayer Hex-star phosphorene (HP) for the CO2 removal from natural gas were investigated by molecular simulation combined with real adsorbed solution theory (RAST). The influences of pressure (0.01–3.0 MPa), molar fraction of CO2 in bulk gas (0.05, 0.1, 0.2, 0.3, 0.4) and pre-adsorbed water content (0.0–9.9 mmol g−1) in adsorbents were thoroughly discussed at 300 K. The adsorption isotherms of both CO2 and CH4 predicted by RAST agree well with the simulation data. The adsorption selectivity calculations indicate that the multilayer HP exhibits an excellent separation performance under high pressure and high CO2 concentration. Meanwhile, under the low CO2 concentration, resulting from the sieving effect and stronger interactions between CO2 and water molecules, the CO2 selectivity can be significantly improved without impact of CO2 loading by pre-adsorbing some water molecules in the multilayer HP. This work suggests that the HP can act as a promising material for natural gas purification.

CO2 Adsorption in Metal-Organic Framework Mg-MOF-74: Effects of Inter-Crystalline Space.

Metal-Organic Frameworks (MOF) have been identified as highly efficient nanoporous adsorbents for CO2 storage. In particular, Mg-MOF-74 has been shown to promise exceptionally high CO2 sorption. Although several studies have reported adsorption isotherms of CO2 in Mg-MOF-74, the effect of inter-crystalline spacing in Mg-MOF-74 on the sorption of CO2 has not been addressed. These effects have been shown to be profound for a quadrupolar molecule like CO2 in the case of silicalite (Phys. Chem. Chem. Phys. 22 (2020) 13951). Here, we report the effects of inter-crystalline spacing on the adsorption of CO2 in Mg-MOF-74, studied using grand canonical Monte Carlo (GCMC) simulations. The inter-crystalline spacing is found to enhance adsorption at the crystallite surfaces. Larger inter-crystalline spacing up to twice the kinetic diameter of CO2 results in higher adsorption and larger crystallite sizes suppress adsorption. Magnitudes of the inter-crystalline space relative to the kinetic diameter of the adsorbed fluid and the surface to volume ratio of the adsorbent crystallites are found to be important factors determining the adsorption amounts. The results of this study suggest that the ideal Mg-MOF-74 sample for CO2 storage applications should have smaller crystallites separated from each other with an inter-crystalline space of approximately twice the kinetic diameter of CO2.

Production of negative-emission biomethane by twin double-bed pressure swing adsorption with tail gas sequestration

Selective removal of CO2 during biogas upgrading and subsequent sequestration can transform the produced biomethane from a carbon-neutral to carbon-negative energy source. Such technology can be considered as bioenergy with carbon capture and storage (BECCS), i.e., as a negative-emission technology (NET). In this research, porous polymeric beads (PPBs) with a practical working capacity above atmospheric pressure and cyclic performance were developed to be used for biogas upgrading by pressure swing adsorption (PSA) without the need for vacuum. The CO2 and CH4 equilibrium isotherms of PPBs were measured in the temperature range of 0–70 °C and in the pressure range of 0–10 bar. The dynamic breakthrough curves of 40:60 (vol%) CO2/CH4 gas mixture were measured at 2 bar and 10 bar. These isotherms and breakthrough curves were used as inputs in a dynamic PSA simulation model to predict the performance of a twin double-bed PSA biogas upgrading process. The model indicated that biomethane with 91% CH4 recovery can be produced and a stream of >90% CO2 purity from the tail gas, suitable for geological storage, can be separated. It should be highlighted that unlike current state-of-the-art PSA units, the proposed process using PPBs can upgrade biogas with minimal energy consumption for regeneration of adsorbents. The proposed selective tail gas separation scheme can be used to produce carbon-negative biomethane.

Carbon Dioxide Capture in Homogeneous and Heterogeneous Surfaces of Porous Silica Glass

Experimental and simulation studies for carbon dioxide (CO2) adsorption on porous silica glass were performed to reveal how surface heterogeneity can affect the adsorption mechanism of CO2. In performing the simulation, the structure of porous silica glass was modeled as a slit pore consisting of parallel walls of connected SiO4 units. The adsorption isotherms of CO2 at 283 K were generated for a series of pore widths using a Monte Carlo ensemble. The defective surfaces created by random removal of surface atoms and the surfaces containing hydroxyl functional groups were chosen to represent the surface heterogeneity for the simulation tasks. The isotherms derived for the defective surfaces showed a rapid adsorption at low pressures because of the stronger interaction between the rough nonuniform surfaces and CO2 molecules. For the role of surface functional groups, the adsorption isotherms dramatically increased with an increasing number of functional groups. The amount of CO2 adsorbed for randomly placed functional groups was greater than that for the presence of functional groups at the pore edges. The proper control of surface heterogeneity by manipulating both the amounts of hydroxyl surface groups and surface defects should help enhance the efficient capture of CO2 in porous silica glass.

A Case Study of Waste Scrap Tyre-Derived Carbon Black Tested for Nitrogen, Carbon Dioxide, and Cyclohexane Adsorption.

Waste scrap tyres were thermally decomposed at the temperature of 600 °C and heating rate of 10 °C·min−1. Decomposition was followed by the TG analysis. The resulting pyrolytic carbon black was chemically activated by a KOH solution at 800 °C. Activated and non-activated carbon black were investigated using high pressure thermogravimetry, where adsorption isotherms of N2, CO2, and cyclohexane were determined. Isotherms were determined over a wide range of pressure, 0.03–4.5 MPa for N2 and 0.03–2 MPa for CO2. In non-activated carbon black, for the same pressure and temperature, a five times greater gas uptake of CO2 than N2 was determined. Contrary to non-activated carbon black, activated carbon black showed improved textural properties with a well-developed irregular mesoporous-macroporous structure with a significant amount of micropores. The sorption capacity of pyrolytic carbon black was also increased by activation. The uptake of CO2 was three times and for cyclohexane ten times higher in activated carbon black than in the non-activated one. Specific surface areas evaluated from linearized forms of Langmuir isotherm and the BET isotherm revealed that for both methods, the values are comparable for non-activated carbon black measured by CO2 and for activated carbon black measured by cyclohexane. It was found out that the N2 sorption capacity of carbon black depends only on its specific surface area size, contrary to CO2 sorption capacity, which is affected by both the size of specific surface area and the nature of carbon black.

Binary- and Pure-Component Adsorption of CO2, H2O, and C6H14 on SSZ-13

Adsorption isotherms on Na-SSZ-13, a small-pore zeolite, for pure-component adsorbates CO2, H2O, and C6H14 were measured using a gravimetric adsorption instrument with a temperature range between 30 and 100 °C. These isotherm data were fit to a multisite Langmuir adsorption model. Using the same gravimetric adsorption instrument, binary adsorption isotherms for the adsorbate pairs CO2–H2O and CO2–C6H14 were measured with a temperature range between 30 and 80 °C. These data demonstrated that the increasing loading of either H2O or C6H14 impacted the loading of CO2 on Na-SSZ-13. The binary isotherm data were compared with ideal adsorbed solution theory and showed relatively good agreement between the data and modeling.

Upgrading pipeline-quality natural gas to liquefied-quality via pressure swing adsorption using MIL-101(Cr) as adsorbent to remove CO2 and H2S from the gas

We experimentally studied removal of acid gas from natural gas via a pressure swing adsorption (PSA) process that employed a metal–organic framework adsorbent, MIL-101(Cr) to upgrade raw-quality natural gas to liquefied-quality natural gas. We hydrothermally synthesized MIL-101(Cr) in the presence of acetic acid, and then we extrudated it using a 15% carboxymethyl cellulose (CMC) binder. The adsorption isotherms of CO2 and CH4 in the pressure range 0–3 MPa and H2S in the pressure range 0–0.1 MPa for both powder- and extrudate-form of the MIL-101(Cr) were measured. The CO2 and CH4 adsorption capacities at 3 MPa were found to be 26.31 and 8.89 mmol/g for powder-form and 19.26 mmol/g and 6.04 mmol/g for extrudate-form, respectively. The H2S adsorption capacities at 0.1 MPa were found to be 7.28 mmol/g for powder-form and 4.04 mmol/g for extrudate-form. Feasibility tests for upgrading 2 vol% CO2−98 vol% CH4 and 2% CO2−0.02% H2S−97.98% CH4 into liquefied-quality natural gas (CO2 < 50 ppm and H2S < 4 ppm) via PSA were performed under various operating conditions (e.g., feed gas pressure (Pfeed), amounts of purge gas (Qpurge), and feed linear velocities (Vlinear). In the case of 2 vol% CO2–98 vol% CH4, the extrudate-form exhibited 1.55 mmol CO2/g (i.e., 94% of the adsorption capacity at PCO2 = 0.12 MPa), under the condition of Vlinear = 0.127 m/s, Qpurge = 178.97 cm3/g, and Pfeed = 6 MPa. Upgrading 2% CO2 + 0.02% H2S + 97.98% CH4 via PSA was found to be difficult because of the strong adsorption of H2S to MIL-101 under the aforementioned conditions.

Poly(s-triazine) based porous carbon for CO2 sequestration

Nitrogen containing microporous materials are promising candidates for the efficient and selective CO2 capture. Triazine containing polyaminals are the potential precursors for the preparation of porous carbons. The various nitrogen moieties present in the materials are examined by XPS analysis. The FE-SEM and HR-TEM images of the materials and N2 sorption profile exhibit abundant microporous structure. Pore size distribution reveals the existence of narrow micropores in the materials. The prepared materials exhibit surface area up to 684 m2/g, microporous surface area up to 441 m2/g and CO2 capture up to 154 mg/g. CO2 isotherm data is well fitted with Langmuir and Freundlich isotherm models. Spontaneity of the CO2 adsorption process are demonstrated by thermodynamic parameters. The high CO2/N2 selectivity and considerable CO2/CH4 selectivity of the materials are calculated by initial slope method (Henry's law).

Fabrication of polyacrylonitrile hybrid nanofiber scaffold containing activated carbon by electrospinning process as nanofilter media for SO2, CO2, and CH4 adsorption

AbstractDistribution of particulate matter (PM), toxic, and greenhouse gases in the atmosphere are responsible for air pollution, human health issues, and enhanced global warming. Traditional polymeric nanofibers only can remove PMs from air flue. The objective of this study was to investigate the adsorption capacity and selectivity of hybrid nanofibrous filter media based on polyacrylonitrile (PAN) with different percentages of activated carbon particles such as gas adsorbent for removal of sulfur dioxide (SO2), carbon dioxide (CO2), and methane (CH4) from gaseous streams The adsorption isotherms of SO2, CO2, and CH4 on the hybrid samples were measured at 298, 323, and 348 K and with a pressure range of 0–21 bar by means of the volumetric adsorption method. Uniform PAN nanofiber filter (PANNF) with an average diameter of 273 nm was achieved via the electrospinning process after the optimization of different parameters. Waste tea‐derived activated carbons (ACs) by using phosphoric acid as the activation agent was synthesized through two different methods, chemical activation to obtain the micro size of AC (MAC), and microwave radiation energy to obtain nano size of AC (NAC). Hybrid nanofibers were functionalized with dispersing homogenous solutions containing AC particles by the electrospray process. The effect of high and low loading of NAC and MAC on the PANNF surface was studied to increase our understanding about gas adsorption properties of prepare samples. The samples were characterized by Image analysis (ImageJ), Statistical package for social science (SPSS), Scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR), Energy‐Dispersive x‐ray (EDX), and Nitrogen adsorption/desorption isotherms.

Electro-assisted adsorption of Cs(I) and Co(II) from aqueous solution by capacitive deionization with activated carbon cloth/graphene oxide composite electrode

In this study, a new composite of activated carbon cloth/graphene oxide (ACC/GO) was prepared, characterized and used as electrode material for the electro-assisted adsorptive removal of Co2+ and Cs+ from aqueous solution. The ACC/GO composite was synthesized by a vacuum filtration method, and characterized by cyclic voltammetry and various surface characterization methods. Effect of applied voltage and initial concentration of Co2+ and Cs+ on their removal efficiency was examined. The kinetics and isotherms of Co2+ and Cs+ adsorption were investigated to explain the adsorption mechanism. At 0 V, the removal efficiency of Co2+ and Cs+ was 10.1% and 21.4%; at 1.2 V, electro-assistance increased the removal efficiency of Co2+ and Cs+ to 40.8% and 39.7%, respectively. Moreover, ACC/GO composite electrode had higher adsorption capacity compared to the pristine ACC electrode, due to its higher specific surface area and more oxygen-containing functional groups. The maximum adsorption capacity of Co2+ and Cs+ was 16.7 mg g−1 and 22.9 mg g−1, respectively at 1.2 V and 20 mg L−1 by ACC/GO composite electrode. The modeling and experimental results demonstrated that the removal mechanism involved in physical adsorption, chemical adsorption, and electro-adsorption. Overall, the prepared ACC/GO composite electrode had high capacitive deionization performance in removing heavy metal ions from wastewater.

Effect of Kerogen Maturity, Water Content for Carbon Dioxide, Methane, and Their Mixture Adsorption and Diffusion in Kerogen: A Computational Investigation.

The adsorption behavior of CO2, CH4, and CO2/CH4 mixtures in four different mature kerogens in the absence/presence of water was studied using grand canonical Monte Carlo and classical molecular dynamics methods. The results exhibit that the adsorption isotherms of single-component CO2 or CH4 in kerogen present similar trends and show type I Langmuir adsorption behavior according to the IUPAC classification; the total adsorbed amount of both gases follows the order of type II-A < type II-B < type II-C < type II-D kerogen under the same conditions. The changing behavior of isosteric heat decreases first and then increases, which can explain the heterogeneous characteristic of the kerogen pore surface. The Coulombic and van der Waals interactions between CO2 and kerogens play an important role on adsorption, while for CH4 adsorption, the electrostatic effect is very small, even negligible. The N-, S-, and O-containing groups in kerogen have more remarkable influence on adsorption of CO2 than CH4 because of their strong adsorption energy, therefore notably improving the selectivity of CO2 over CH4 and following the order of type II-A > type II-B > type II-C > type II-D, which is beneficial to carbon capture and storage. Both pressure and temperature have an obvious impact on gas molecule diffusion, and low pressure and high temperature correspond to a large diffusion coefficient. In addition, preabsorbed water has a negative effect on the adsorption of CO2/CH4, and for the same amount of water molecules, the effect follows the order of type II-A > type II-B > type II-C > type II-D kerogens. The binding energy of water-kerogen is stronger than that of pure CH4 or CO2-kerogen. The selectivity of CO2 over CH4 on kerogen increases with an increasing water content.

Assessment of the potential use of zeolites synthesized from power plant fly ash to capture CO2 under post-combustion scenario

Two types of zeolites (type X and type A) were synthesized from fly ash of two Brazilian coal based power plants via hydrothermal treatment after ash fusion with NaOH. The synthesized zeolites were characterized by means of XRF, XRD, SEM and gas adsorption (N2 and CO2 adsorption/desorption at − 196 and 0 °C, respectively). Pure CO2 and N2 adsorption equilibrium isotherms were performed at 50, 70 and 90 °C to measure the CO2 adsorption capacity and selectivity of CO2 over N2. CO2/N2 binary isotherms (15/85% v/v) were also obtained at the same temperatures. Commercial zeolitic materials used for CO2/N2 separation such as zeolite 13X and zeolite 4A underwent the same characterization and adsorption measurements as benchmarks to evaluate the performance of the synthesized zeolites. The synthesized materials from fly ash are promising low cost adsorbents for CO2 separation, reaching ca. 83% of the CO2 adsorption capacity of their commercial counterparts at 0.15 bar and 50 °C.

Experiment and Modeling of Adsorption of CO from Blast Furnace Gas onto CuCl/Boehmite

Adsorption of CO, CO2 and N2 gas on a CuCl/Boehmite is studied in static and dynamic experiments to separate CO from blast furnace gas (BFG). The adsorption isotherms of CO, CO2 and N2 were measure...

The Effect of Sterically Active Ligand Substituents on Gas Adsorption within a Family of 3D Zn-Based Coordination Polymers

An investigation of the adsorption properties of two structurally related, 3D coordination polymers of composition Zn(2-Mehba) and Zn(2,6-Me2hba) (2-Mehba = the dianion of 2-methyl-4-hydroxybenzoic acid and 2,6-Me2hba = the dianion of 2,6-dimethyl-4-hydroxybenzoic acid) is presented. A common feature of these structures are parallel channels that are able to accommodate appropriately sized guest molecules. The structures differ with respect to the steric congestion within the channels arising from methyl groups appended to the bridging ligands of the network. The host network, Zn(2-Mehba), is able to take up appreciable quantities of H2 (77 K) and CO2 and CH4 (298 K) in a reversible manner. In regard to the adsorption of N2 by Zn(2-Mehba), there appears to be an unusual temperature dependence for the uptake of the gas such that when the temperature is increased from 77 to 298 K the uptake of N2 increases. The relatively narrow channels of Zn(2,6-Me2hba) are too small to allow the uptake of N2 and CH4, but H2 molecules can be adsorbed. A pronounced step at elevated pressures in CO2 and N2O isotherms for Zn(2,6-Me2hba) is noted. Calculations indicate that rotation of phenolate rings leads to a change in the available intraframework space during CO2 dosing.

Microbial Methane Oxidation and Gas Adsorption Capacities of Biochar-Modified Soils

Biochar has been recently considered as a potential soil additive to mitigate the landfill gas emissions in the soil cover. Some physical and chemical properties of biochar, like high phosphorus and organic matter contents, porous structures, and high specific surface area, are prone it a good soil amendment material to enhance the microbial methane oxidation and gas adsorption capacities of the soils. Three different types of biochar: wood chip, two herbaceous biomasses (corn straw and rice straw), were used to modify a silty soil in this study. Microbial CH4 oxidation and CH4 and CO2 adsorption capacities of the modified soils were investigated by the batch tests. The test results showed that the maximum methane oxidation rate (MOmax) of the soil modified by 30% biochar content (Bc) was 3–4 times that of the host soil. An optimum Bc corresponding to the peak value of MOmax was identified. For the three biochars tested, the optimum Bc ranged between 20 and 30% and soil modified by wood-derived biochar exhibits the highest MOmax, because woody biochar has the highest specific surface area and lower pH. Moreover, MOmax also increased with the preincubation time. It is suggested that preincubated sample has the advantage over the fresh sample for building up the content of methanotrophs in the soil before constructing the cover system. The adsorption kinetics and isotherms of CH4 and CO2 in the modified soils followed the pseudo-second-order equation and Langmuir model, respectively. By adding 20% Bc, the maximum adsorption capacity of CH4 and CO2 in the modified soil was about 54 times and 80 times that of the host soil, respectively.

Effect of shale properties on CH4 and CO2 sorption capacity in Czech Silurian shales

The study involved an experimental assessment of the CO2 and CH4 sorption capacity of seven dark Silurian shale samples from three formations in the Barrandian Basin (Czech Republic). The shale samples had dominant inorganic matter consisting mainly of clay minerals, quartz, calcite and plagioclase, and very low organic matter. Most of the organic particles were the remains of zooclasts, especially graptolites and bitumens. The graptolite reflectance (Rr) reflecting the degree of thermal maturation of the shales ranges between 0.56% in the Kopanina Formation and 1.09% in the Litohlavy Formation, with the exception of the probably thermally altered part of the Motol Formation, which has reflectance higher than 1.70%. The total organic carbon (TOC) content was found to be in the range of 0.34–2.37 wt%. The porosity values were from 4.6% to 18.8%. In all shale samples, the high pressure excess sorption isotherms of CO2 and CH4 were measured at a temperature of 45 °C for both gases at pressures up to 8 MPa for CO2 and up to 15 MPa for CH4 on dry samples, using a manometric sorption apparatus. The Gibbs equation was used for evaluation of the maximum excess sorption (nmax,CO2 and nmax,CH4). The nmax,CO2 values ranged from 0.118 mmol/g to 0.244 mmol/g, while the nmax,CH4 values were more than twice lower (0.050 mmol/g - 0.088 mmol/g). The xCO2/CH4 ratio ranged from 1.47 to 2.98, with a median value of 2.54, calculated without the sample from the Kopanina Formation (4.36). The influence of the shale parameters on the CO2 and CH4 sorption capacity was determined. No relation has been proven between the value of Rr and the TOC-normalized CO2 and CH4 sorption capacities. The CO2 sorption capacity showed a negative correlation with TOC and with clay minerals but a positive correlation with quartz, while the behaviour of CH4 was opposite in these cases. A strong positive correlation was found between the volume of micropores and the CO2 excess sorption capacity, and negative dependence was found for CH4. The CO2 sorption capacities always depend on the micropores content, and the CH4 capacities depend on the shale components.

Adsorption mechanism of methyl iodide by triethylenediamine and quinuclidine-impregnated activated carbons at extremely low pressures

Activated carbons impregnated with 1, 5, and 10 wt% triethylenediamine (TEDA) and quinuclidine (QD) were prepared for the removal of methyl iodide (CH3I) gas. The textural properties of the impregnated activated carbons were characterized by N2 and CO2 isotherms at 77 K and 273 K, respectively. The adsorption isotherms of CH3I was obtained at 283, 293, and 303 K and at pressures up to 250 Pa using a self-made volumetric system with resolution of 10−3 Pa. All the experimental isotherms were fitted by the Langmuir and Toth models, and the initial part of the uptake curve was fitted by the Fick’s diffusion model. Furthermore, the adsorption heats were analyzed by the van’t Hoff and Clausius–Clapeyron equations. The adsorption characteristics of TEDA- and QD-impregnated activated carbons, such as the isotherms, thermodynamic heats, and adsorption rate, were compared at very low pressures (less than 20 Pa). The adsorption behaviors are affected by the type and amount of impregnant and textural properties. The impregnant-rich activated carbon is beneficial for the removal of CH3I at low pressures, while the less impregnated AC with high porosity shows a relatively high adsorption capacity under a high pressure. It indicates that the physisorption and chemisorption of CH3I occur simultaneously, but the contribution of chemisorption to the removal of CH3I increases with the amount of impregnant. The adsorption rate is more affected by alkylated (chemisorbed) products than impregnants.