CO2 Sorption Capacity Research Articles

Adsorptive capture of CO2 by amine‐impregnated activated carbon, pumice, and zeolite 4A

AbstractThis study provides comparative information about CO2 capture of raw and amine‐impregnated micro‐, meso‐, and macroporous support materials. Zeolite 4A (4A), activated carbon (AC), and pumice (P) were used as micro‐, meso‐, and macroporous support materials, respectively, and monoethanolamine (MEA) and diethanolamine (DEA) were used as the immobilized liquid. Adsorption of CO2 from CO2‐N2 mixtures (3–28%, v/v) was performed in a constant volume‐variable pressure cell at 293 ± 2 K, and desorption of saturated sorbents was carried out at 373 ± 2 K. The textural properties of the porous supports have been seen to play an important role in amine loading into the pores and the mass transport of CO2 into/from the amine‐loaded pores. Among the porous supports, despite its lower surface area, pumice with a macroporous backbone helped immobilization of a large amount of amine and facilitated the CO2 sorption and desorption. Amine loading increased the CO2 capture efficiencies of activated carbon, pumice, and zeolite 4A as 13.4, 19.1, and 5.4 times for MEA and 6.2, 8.8, and 4.1 times for DEA, respectively. It was found that the CO2 release rates from MEA‐ and DEA‐impregnated 4A, AC, and P were 0.215, 0.475, and 0.556 mg CO2·g sorbent–1·min–1 and 0.242, 0.580, and 0.670 mg CO2·g sorbent–1·min–1, respectively, at 373 ± 2 K and 1 kPa. The CO2 sorption capacities of the MEA‐impregnated support materials from the cyclic operation were affected negatively more than the DEA‐impregnated ones and this effect increased from the microporous support material to the macroporous. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Multifunctional Lanthanide-Based Metal-Organic Frameworks Derived from 3-Amino-4-hydroxybenzoate: Single-Molecule Magnet Behavior, Luminescent Properties for Thermometry, and CO2 Adsorptive Capacity.

Herein, we describe and study a new family of isostructural multifunctional metal–organic frameworks (MOFs) with the formula {[Ln5L6(OH)3(DMF)3]·5H2O}n (where (H2L) is 3-amino-4-hydroxybenzoic acid ligand) for magnetism and photoluminescence. Interestingly, three of the materials (Dy-, Er-, and Yb-based MOFs) present single-molecule magnet (SMM) behavior derived from the magnetic anisotropy of the lanthanide ions as a consequence of the adequate electronic distribution of the coordination environment. Additionally, photoluminescence properties of the ligand in combination with Eu and Tb counterparts were studied, including the heterometallic Eu–Tb mixed MOF that shows potential as ratiometric luminescent thermometers. Finally, the porous nature of the framework allowed showing the CO2 sorption capacity.

Single-step fabrication of templated Li4SiO4-based pellets for CO2 capture at high temperature

The present study proposes a novel single-step method for the fabrication of macro-porous K2CO3-doped Li4SiO4 pellets for carbon dioxide capture at high temperature and low concentration of CO2. Cylindrical pellets were directly prepared by mechanical compression of precursors and then calcination at high temperature. The pellets characterization evidenced that, during the calcination process, both the synthesis of Li4SiO4 and the development of macro-porosity into pellets occurred due to the release of decomposition gases. The obtained pellets were tested for CO2 capture at 580 °C and CO2 partial pressure of 0.04 atm, and the long-time stability was evaluated by multiple sorption/desorption cycles operating at moderate Li4SiO4 conversions. This single-step pelletization method allowed to produce a sorbent with high CO2 sorption capacity (253.2 mg CO2/g sorbent) even at low concentration of CO2. Moreover, the single-step pellets displayed a good cyclic stability over 200 adsorption/desorption cycles, making them suitable for CO2 capture in industrial applications in a fixed bed reactor.

High temperature CO2 capture performance and kinetic analysis of Na4SiO4 ceramics

Alkali silicate-based ceramics sorbents were regarded as particularly suitable materials for CO2 capture at high temperatures, however, the CO2 capture behaviors of Na4SiO4 had been seldom investigated. In this work, the Na4SiO4 ceramics samples were prepared using the one-step synthesized method, and the CO2 sorption/desorption performances at high temperatures, the thermal stability, and the cycling stability of Na4SiO4 were systematically investigated. It was demonstrated that the maximum CO2 sorption capacity of SO-3 sample reached 19.4 wt% at 725 °C, and the optimal condition of cycling tests were 750 °C for sorption and 800 °C for desorption based on the sorption/desorption capacity and rate, which exhibited good thermal stability and high cyclic stability. Besides, the kinetic analysis results showed that the diffusion process was the rate-determining step of CO2 adsorption, which was more dependent on temperature than the chemisorption process. The structure and surface morphology variations were also investigated, it was interesting that there was a special “fish scale” surface structure after the sorption process, revealing that the melting phenomenon happened during the chemisorption reaction process. By comparing with common sorbent Li4SiO4, the material and CO2 capture costs of Na4SiO4 were much lower. These results proved that Na4SiO4 was expected to be a suitable high temperature CO2 capture material as a good supplement to alkali silicate-based ceramics sorbents.

A green approach towards sorption of CO2 on waste derived biochar

Carbon capture technologies have advanced in recent years to meet the ever-increasing quest to minimize excessive anthropogenic CO2 emissions. The most promising option for CO2 control has been identified as carbon capture and storage. Among the numerous sorbents, char generated from biomass thermal conversion has shown to be an efficient CO2 adsorbent. This study examines various characteristics that can be used to increase the yield of biochar suited for carbon sequestration. This review gives recent research progress in the area, stressing the variations and consequences of various preparation processes on textural features such as surface area, pore size and sorption performance with respect to CO2's sorption capacity. The adjoining gaps discovered in this field have also been highlighted herewith, which will serve as future work possibility. It aims to analyse and describe the possibilities and potential of employing pristine and modified biochar as a medium of CO2 capture. It also examines the parameters that influence biochar's CO2 adsorption ability and pertinent challenges regarding the production of biochar-based CO2 sorbent materials.

Thermochemical study of CO2 capture by mesoporous silica gel loaded with the amino acid ionic liquid 1-ethyl-3-methylimidazolium glycinate

A series of composite CO2 sorbents were obtained by placing an amino acid ionic liquid (AAIL) 1-Ethyl-3-methylimidazolium glycine ([Emim][Gly]) into mesoporous silica gel using an impregnation method. The parameters of the porous structure for the silica support and composite sorbents were determined from nitrogen adsorption-desorption isotherms measured at 77 K. The morphology of the materials was studied using field-emission scanning electron microscopy. It was shown that at lower [Emim][Gly] loadings (<50 wt%), the sorption is fast and the dynamic CO2 sorption capacity of the material is proportional to the mass content of the AAIL. At higher [Emim][Gly] loadings (≥50 wt%), the rate of CO2 sorption by the AAIL decreases due to hindered mass transfer. An increase in CO2 concentration in the gas flow leads to a faster sorption and higher CO2 sorption capacity for the AAIL-containing composite. Meanwhile, the integral enthalpy of sorption decreases with increasing CO2 concentration, which can be explained by the greater contribution of physical adsorption/absorption processes to the total CO2 sorption capacity at higher CO2 concentrations. The most promising composite material (40 wt% [Emim][Gly]/SiO2) was tested in consecutive temperature-swing sorption-desorption cycles. It was demonstrated that lowering the regeneration temperature from 100 to 80 °C leads to a decrease in the dynamic sorption capacity of the material, but ensures its stability in the cyclic sorption-desorption process.

From biopolymer dissolution to CO2 capture under atmospheric pressure - A molecular view on biopolymer@Ionic liquid materials

Finding a cheap and easily recycling material that can capture CO2 under atmospheric pressure (1 atm) is of paramount importance. In this context, combining ionic liquids (ILs) with abundant and natural materials, such as chitin-based biopolymers, appears as an interesting alternative. In this work, four acetate-based ILs were selected to explore the solubility of chitin, chitosan, and carboxymethyl-chitosan. Using carboxymethyl-chitosan and biopolymer monomer units as models, different Nuclear Magnetic Resonance (NMR) techniques, namely, 1H, 13C, nuclear Overhauser effect spectroscopy, and spin-lattice relaxation, were performed to evaluate the dissolution. Shrimp shells were used as a chitin source. Through a simple acid/base treatment, it was possible to remove minerals and proteins, and use it to prepare biopolymer@IL materials for CO2 capture tests. Efficient CO2 sorption capacity was observed upon bubbling CO2 with a maximum of 2.32 mmolCO2/gsorbent. Under N2 bubbling, the system demonstrated excellent recycling capacity using a room temperature procedure that outperformed aqueous amine solutions recycling. The absence of heating and vacuum recycling procedures, combined with the use of N2 or compressed air is much more appealing for industrial applications.

Synthetic silico-metallic mineral particles SSMMP: A new option for CO2 capture and CO2/N2 separation from post-combustion technology

A new class of solid adsorbents based on pristine and ionic liquid (IL) functionalized synthetic silico-metallic mineral particles (SSMMP) for CO2 capture and CO2/N2 separation are presented. Pristine particles were submitted to hydrothermal treatment producing synthetic talc. Samples were characterized by thermal analyses (TGA), specific surface area measurements (BET), infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction(XRD), NMR spectroscopy, and scanning electron microscopy (SEM). Values for specific surface areas varied from 5 m2/g for a sample with high IL content to 354 m2/g for pristine SSMMP. Samples presented distinct morphology as well as sorption capacities. IL and its increased concentration in the samples negatively influenced CO2 sorption capacity but played an essential role in CO2/N2 selectivity. The best results were obtained from CO2 sorption values for SSMMP-M1 without IL of 2.07 mmol CO2/g at 1 bar and 4.93 mmol CO2/g at 30 bar. In addition, a selectivity of 16.94 for the CO2/N2 mixture was achieved for SSMMP-5%-Im(nBu)-I sample. SSMMP particles are easy to obtain with low-cost starting materials used in the low energy and CO2-free emission synthesis process. The sorption/desorption cycles proved the stability for both pristine and IL functionalized samples.

Semiconductor Porous Hydrogen-Bonded Organic Frameworks Based on Tetrathiafulvalene Derivatives.

Herein, we report on the use of tetrathiavulvalene-tetrabenzoic acid, H4TTFTB, to engender semiconductivity in porous hydrogen-bonded organic frameworks (HOFs). By tuning the synthetic conditions, three different polymorphs have been obtained, denoted MUV-20a, MUV-20b, and MUV-21, all of them presenting open structures (22, 15, and 27%, respectively) and suitable TTF stacking for efficient orbital overlap. Whereas MUV-21 collapses during the activation process, MUV-20a and MUV-20b offer high stability evacuation, with a CO2 sorption capacity of 1.91 and 1.71 mmol g–1, respectively, at 10 °C and 6 bar. Interestingly, both MUV-20a and MUV-20b present a zwitterionic character with a positively charged TTF core and a negatively charged carboxylate group. First-principles calculations predict the emergence of remarkable charge transport by means of a through-space hopping mechanism fostered by an efficient TTF π–π stacking and the spontaneous formation of persistent charge carriers in the form of radical TTF•+ units. Transport measurements confirm the efficient charge transport in zwitterionic MUV-20a and MUV-20b with no need for postsynthetic treatment (e.g., electrochemical oxidation or doping), demonstrating the semiconductor nature of these HOFs with record experimental conductivities of 6.07 × 10–7 (MUV-20a) and 1.35 × 10–6 S cm–1 (MUV-20b).

Underlying Polar and Nonpolar Modification MOF-Based Factors that Influence Permanent Porosity in Porous Liquids.

It is increasingly apparent that porous liquids (PLs) have unique use cases due to the combination of ready liquid handling and their inherently high adsorption capacity. Among the PL types, those with permanent porosity are the most promising. Although Type II and III PLs have economic synthetic methods and can be made from a huge variety of metal–organic frameworks (MOFs) and solvents, these nanocomposites still need to be stable to be useful. This work aims to systematically explore the possibilities of creating PLs using different MOF modification methods. This delivered underpinning insights into the molecular-level influence between solvent and MOF on the overall nanocomposite stability. Zirconium-based metal–organic frameworks were combined with two different solvents of varying chemistry to deliver CO2 sorption capacities as high as 2.9 mmol g–1 at 10 bar. The results of the study could have far-reaching ramifications for future investigations in the PL field.

Fibrous Polyethyleneimine‐Functionalized Cellulose Materials for CO2 Capture and Release

AbstractPoly(ethyleneimine) (PEI) immobilized on support materials are valuable alternatives to aqueous amine solutions for carbon dioxide (CO2) capture from the atmosphere since the thermal desorption of CO2 from these materials usually requires less energy. Herein, fibrous PEI‐functionalized carrier systems based on cellulose, cellulose tosylate (CT), and cellulose carbamate (CC) are described. Branched PEI is used for functionalization since higher CO2 sorption capacities compared to linear PEIs can be achieved. Under wet conditions, a PEI‐functionalized nonwoven material has a sorption capacity of 0.026 mg CO2/mg adsorbent; complete and reversible CO2 desorption is accomplished at 80 °C.

Enhancement of carbon dioxide adsorption performances by hydrazinolysis of poly(n-vinylformamide) grafted fibrous adsorbent

Abstract Emission of carbon dioxide (CO2) becomes a main concern in battling issues of global warming. The strategy to reduce the concentration of CO2 could be achieved by implementing carbon capture and storage (CCS) technology such as adsorption by solid adsorbents. In this work, hydrazone containing adsorbent was prepared by radiation induced grafting of N-vinylformamide (NVF) onto polyethylene coated polypropylene (PE/PP) fibrous sheets and subsequent hydrazinolysis for CO2 capture. Hydrazinolysis of the amide group to hydrazone moieties was accelerated by the addition of ammonium salts. These newly prepared adsorbent was characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The adsorption tests of pure CO2 and N2, and their mixture were carried using the gravimetric method. The result revealed that the obtained adsorbent was highly CO2 selective and attained remarkably higher CO2 sorption capacity of 3.1 mmol/g at 30 bar and room temperature compared to 0.3 mmol/g for amide-containing sample. The new adsorbent could be used for few repeated cycles with negligible loss in sorption capacity. Overall, the hydrazone-containing adsorbent has storing potential for CO2 capture, and more studies need to be conducted for further development.

A Review of CO2 Capture by Poly(Ionic liquid)s

Abstract: Over the last two decades, poly(ionic liquid)s (PILs) have undergone extensive research and development. PILs have opened a whole new passage to versatile ionic polymers. It has compelled the chemical industry to rethink its modern ways of carbon capture. PILs have demonstrated excellent CO2 sorption capacities in comparison to their corresponding ionic liquids (ILs). The effects of the chemical structures of PILs on CO2 sorption, including the types of anion, cation, and backbone, have been discussed. This review aims to cover details of a large range of PILs along with their physical and structural properties, synthesis procedures, and the absorption power towards CO2. Imidazolium-based PILs are some of the strongest absorbents of CO2. On the other hand, PILs with amino acid (AA) anion seem to have a much-improved sorption capacity when compared PILs with the non-AA anionic part. PILs with hexafluorophosphate ion (PF6-) relatively absorb more CO2 compared to tetra-fluoroborate (BF4-) based PILs. The solubility of CO¬2 was increased with increasing pressure and decreased as temperature increased. The inclusion of hydroxyl groups in the polycation increased the interaction with CO2 molecules.¬ The COSMO-RS model was used to understand the molecular-level behavior of PILs in terms of their activity coefficients.

Pore size-excluded low viscous porous liquids for CO2 sorption at room temperature and thermodynamic modeling study

Herein, we report porous ionic liquids (type-III) designed to utilize microporous ZIF-8 moieties with functional ionic liquids such as 8-(2-methoxyethyl)-1,8-Diazabicyclo[5.4.0]undec-7-en-8-ium, Bis(trifluoromethane)sulfonamide ([MEDBU][TFSI] and Trioctylammonium 4-para-tert-butylbenzoiate [TOAH][PTBBA]). The prepared materials were thoroughly characterized by means of XRD, FT-IR, SEM, TEM, BET, TGA, DSC and viscometry techniques. The idea of combining the intrinsic properties of ionic liquids with microporous architecture to prepare porous ionic liquids yields promising fluidic materials that have received attention in industrial applications such as gas sorption and separation etc. The prepared porous ionic liquids possess unique physico-chemical properties such as low viscosity, high thermal stability, low vapor pressure, reusability and their fluidic nature renders the materials suitable for CO2 capture. Herein introduced porous ionic liquids (ILs) showed enhanced CO2 uptake (0.92 mmol/g in [TOAH][PTBBA]-Z100 and 1.16 mmol/g in [MEDBU][TFSI]-Z200), or in other words, 15–47% higher sorption capacity compared to neat ionic liquids. This concept overcomes the drawbacks of highly viscous ILs and their limited CO2 sorption capacity. Thermodynamic modeling further demonstrated that the enthalpy of sorption is only −9.99 kJ mol−1, indicating that significantly less energy is required for regeneration. This is promising for the potential use of these fluidic materials in continuous separation processes on an industrial scale, as a better alternative to the existing hazardous amine scrubbing.

Transforming Porous Silica Nanoparticles into Porous Liquids with Different Canopy Structures for CO2 Capture.

Porous liquids (PLs) have both liquid fluidity and solid porosity, thereby offering a variety of applications, such as gas sorption and separation, homogeneous catalysis, energy storage, and so forth. In this research, canopies with varying structures were utilized to modify porous silica nanoparticles to develop Type I PLs. According to experimental results, the molecular weight of canopies should be high enough to maintain the porous materials in the liquid state at room temperature. Characterization results revealed that PL_1_M2070 and PL_1_AC1815 displayed low viscosity and good fluidity. Both low temperature and high pressure positively influenced CO2 capacity. The cavity occupancy resulted in poorer sorption capacity of PLs with branched canopies in comparison with that with linear canopies. Furthermore, the sorption capacity of PL_1_M2070 was 90.5% of the original CO2 sorption capacity after 10 sorption/desorption cycles, indicating excellent recyclability.

Gas-bentonite interactions: Towards a better understanding of gas dynamics in Engineered Barrier Systems

Bentonite is a common backfill material used in Engineered Barrier Systems (EBS) for radioactive waste disposal. Its thermal, hydraulic, and chemical properties have been extensively studied. However, empirical evidence on the interactions with the free gas phase present in its pore space under conditions close to those prevailing in deep geological repositories (i.e., exposure to multiple gas species at temperature and humidity conditions close to those of freshly backfilled EBS) is scarce. This limits the prediction/assessment of the evolution of the gas composition in EBS. Here we present the outcome of laboratory experiments targeting such gas-bentonite interactions using two different types of bentonite (Italian bentonite; Wyoming bentonite) being exposed to atmospheric air in sealed stainless-steel vessels. The results indicate that gas sorption on bentonite can occur at repository-like conditions and is likely to play a significant role in the overall gas dynamics in the backfill of EBS. Drying of both bentonites was shown to partly re-activate their CO2 sorption capacity during a subsequent re-hydration phase. Furthermore, the grinding of Wyoming bentonite resulted in the generation of new pyrite surfaces that significantly enhanced O2 removal from the free gas phase by oxidation. Our initial investigations call for more systematic and extensive series of laboratory experiments in order to quantitatively constrain the different processes involved in gas-bentonite interactions.

Enhanced CO2 capture kinetics by using macroporous carbonized natural fibers impregnated with an ionic liquid

In this research a new hybrid material was prepared to improve the kinetics and CO2 sorption capacity of an ionic liquid supported on the macroporous structure of carbonized agave bagasse fibers, which are low-cost renewable materials. The ionic liquid was 1-butyl-3-methylimidazolium acetate that has high affinity for CO2. The CO2 capture was assessed in a dynamic mode at atmospheric pressure by monitoring the weight change of the fibers in a thermogravimetric analyzer when passing a CO2 gas stream. The CO2 capture was evaluated on carbonized fibers (CF), acid washed carbonized fibers (CFw) and carbonized fibers impregnated with ionic liquid (IL) using a mass ratio that ranges from 1:10−3 to 1:1 (wt CFw: wt IL). The BET surface area of CF was 75 m2/g that decreased after the acid wash to 2 m2/g. However, after impregnation with IL, the surface area was maintained at 2 m2/g when using the lowest impregnation ratio (1:10−3). The impregnated sample with a mass ratio of 1:10−3 (CFwIL1:10−3) exhibited the highest sorption capacity (1.29 mmol CO2/g evaluated at 50 min of CO2 exposure) and sorption rate of 0.02 mmol CO2/min*g. These values were superior to those obtained by the IL (0.77 mmol CO2/g and 0.012 mmol CO2/min*g), which showed the synergy between the IL and the support in the CO2 capture. Finally, the cycles of CO2 capture (25 °C, 50 min) and thermal desorption (80 °C, 50 min, under nitrogen atmosphere) reported that the IL captured up to 1.07 mmol CO2/g but released only 41.5%, in contrast the impregnated carbon fibers (CFwIL1:10−3) captured 1.13 mmol CO2/g and released 91%. The rapid CO2 sorption-desorption processes and high reversibility of the impregnated carbon fibers suggest that this material could be used in CO2 concentrators.

PROMOTION OF COBALT-CONTAINING HYDROTALCITE MATERIALS WITH POTASSIUM, CERIA, AND ZIRCONIA FOR CO2 SORPTION-ASSISTED REFORMING OF BUTANOL TO H2

Sorption-enhanced steam butanol reforming (SESBR) is capable of producing pure hydrogen (H2). In CO2 sorption-enhanced (or sorption-assisted) reaction processes, the application of hybrid bifunctional materials consisting of a reforming catalyst and CO2 sorbent is encouraging. In this work, a novel material (CoMgHTlc, here denoted by HM1) containing cobalt catalyst and Mg-based hydrotalcite was synthesized using the coprecipitation method. HM1 was then promoted with K, Zr, or Ce using incipient wet impregnation to yield K-HM1, Zr-HM1, and Ce-HM1, respectively. SESBR was investigated in a fixed-bed reactor between 723 and 923 K. Gas hourly space velocity (GHSV) was changed between 3000 and 6000 mL/g h. Butanol concentration in the feed was varied to provide steam-to-carbon ratios (S/C) ranging from 3 to 7.5 mol/mol. All materials were stable and exhibited a high pre-breakthrough period. At 873 K, H2 concentration of the product stream was 97.3 mol % over Ce-HM1; the CO2-sorption capacity was 1.43 mol CO2/kg sorbent.

The AEROPILs Generation: Novel Poly(Ionic Liquid)-Based Aerogels for CO2 Capture.

CO2 levels in the atmosphere are increasing exponentially. The current climate change effects motivate an urgent need for new and sustainable materials to capture CO2. Porous materials are particularly interesting for processes that take place near atmospheric pressure. However, materials design should not only consider the morphology, but also the chemical identity of the CO2 sorbent to enhance the affinity towards CO2. Poly(ionic liquid)s (PILs) can enhance CO2 sorption capacity, but tailoring the porosity is still a challenge. Aerogel’s properties grant production strategies that ensure a porosity control. In this work, we joined both worlds, PILs and aerogels, to produce a sustainable CO2 sorbent. PIL-chitosan aerogels (AEROPILs) in the form of beads were successfully obtained with high porosity (94.6–97.0%) and surface areas (270–744 m2/g). AEROPILs were applied for the first time as CO2 sorbents. The combination of PILs with chitosan aerogels generally increased the CO2 sorption capability of these materials, being the maximum CO2 capture capacity obtained (0.70 mmol g−1, at 25 °C and 1 bar) for the CHT:P[DADMA]Cl30% AEROPIL.

Insights into Nickel-Based Dual Function Materials for CO2 Sorption and Methanation: Effect of Reduction Temperature

Ni-MgO dual function materials (DFMs) show promise for integrated CO2 sorption and methanation. To improve CO2 sorption capacity, Ni-MgO DFMs are promoted with alkali metal nitrates. However, the h...