Good CO2 Adsorption Research Articles

Ultrahigh volatile iodine capture by conjugated microporous polymer based on N,N,N′,N′-tetraphenyl-1,4-phenylenediamine

Conjugated microporous polymers based on N,N,N′,N′-tetraphenyl-1,4-phenylenediamine exhibit ultrahigh iodine vapor uptake and good CO2 adsorption.

The N-doped activated carbon derived from sugarcane bagasse for CO2 adsorption

In this study, a highly selective CO2 adsorbent from sugarcane bagasse (waste biomass) was prepared, and the enrichment of nitrogen in the adsorbent was achieved via urea-KOH method. Moreover, the influence of preparing parameters such as urea addition, KOH/carbon ratio and activation temperature on the pore textural properties and CO2 uptake capacity of adsorbents were investigated. Brunauer–Emmet–Teller (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier Transform Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the adsorbents. The results indicated that whereas the temperature and pressure of 25 °C and 1 bar, the adsorbent had the highest CO2 uptake of 4.8 mmol/g. The preparation condition of the adsorbent was at 600 °C with 15 wt% urea additions and KOH/carbon ratio of 2.0. It was also found that there were pyridinic-N (N-6), pyrrolic-/pyridonic-N (N-5), quaternary-N (N–Q) and pyridine-N-oxide (N–X) functional groups at the surface. At the same time, the SB-AC had uniform micropores (∼0.55 nm). Hence, the adsorbent had an excellent CO2/N2 selectivity. The CO2 uptake of the adsorbent was almost identical during the five runs of CO2 adsorption/desorption measurements, indicating good stability and regenerability CO2 adsorption. The narrow micro-pore volume (pore width ≤ 1 nm) fraction and N content in SB-ACs were 80–89% and 0.6–3.34 wt%, respectively. The results led to the conclusion that the narrow micropores and N content in the adsorbent were considered as the important roles for CO2 adsorption.

Pollutant Removal from Gaseous and Aqueous Phases using Hydrochar-based Activated Carbon

In this study, hydrochar (HC) produced at industrial scale by hydrothermal carbonization of municipal woody and herbaceous prunings was used for producing activated carbon by KOH chemical activation. Different KOH/HC ratios were studied to produce highly porous materials with high surface area. Activated carbon with a BET surface area up to 1739 m2/g was obtained for a 3:1 KOH/HC ratio. Adsorption properties of obtained samples were studied for removing pollutants both from gas and liquid phases. Thermogravimetric analyzer (TGA) was used for evaluating the removal capacities of CO2 from a gaseous phase, while UV-Vis spectroscopy was used for evaluating the removal capacities of an emerging contaminant from an aqueous phase. All samples showed a good CO2 adsorption capacity at 27 °C, reaching 84.5 mg CO2/g sorbent for hydrochar activated with an impregnation ratio of 2:1. Moreover, activated chars exhibited a high removal efficiency (up to 97.9 % for a 3:1 KOH/HC ratio) for atrazine, which is one of the most common pesticides detected in superficial and groundwater aquifers.

In Situ Synthesis of Nitrogen-Enriched Activated Carbons from Procambarus clarkii Shells with Enhanced CO2 Adsorption Performance

Highly microporous nitrogen-enriched activated carbons were in situ synthesized by using K2C2O4·H2O as an activating agent and Procambarus clarkii shells as a carbon and nitrogen (N) source. The obtained samples exhibit good CO2 adsorption performance at 1 bar ranging from 4.99 to 6.48 mmol/g at 0 °C, and from 2.55 to 4.51 mmol/g at 25 °C, respectively. In particular, a high CO2 adsorption capacity of 4.51 mmol/g at 25 °C was achieved for the sample prepared by using the K2C2O4·H2O/precursor mass ratio of 3 and activated at 700 °C. The high CO2 uptake was achieved because of a unique microporous structure and high N content. Furthermore, the CO2/N2 selectivity and CO2 adsorption heat of this carbon are as high as 52 and 33 kJ/mol, respectively. In addition, this carbon exhibits excellent reusable stability and a high dynamic CO2 capture capacity of 0.79 mmol/g under conditions mimicking aflue gas environment. The aforementioned advantages demonstrate that the obtained N-enriched activated carbon can be a ...

Hydroxylamine-Anchored Covalent Aromatic Polymer for CO2 Adsorption and Fixation into Cyclic Carbonates

Hydroxylamine-anchored covalent aromatic polymer (CAP-DAP) was synthesized from p-terphenyl and 1,3,5-benzene tricarbonyl chloride, followed by subsequent functionalization with 1,3-diamino-2-propanol for CO2 capture and metal-free catalysis in CO2–epoxide cycloaddition reactions. The novel CAP-DAP material was characterized using various analytical techniques. It showed very good CO2 adsorption capacity of 153 mg/g along with a high (CO2/N2) selectivity of 86 at 273 K/1 bar, in contrast to bare CAP, which exhibited moderate CO2 adsorption of 136 mg/g with a CO2/N2 selectivity of 47. CAP-DAP also displayed high catalytic activity for CO2–epoxide cycloaddition reactions under mild and solvent-free conditions. The synergistic effect between metal-free CAP-DAP and tetrabutylammonium bromide (n-Bu4NBr) enabled a high epoxide conversion of 98% coupled with an excellent product selectivity of 99% at 60 °C, 1 bar CO2, and a reaction time of 12 h. Faster reaction kinetics with reaction times <6 h was possible at ...

Ni‐Ce/Zeolites for CO2 Hydrogenation to CH4: Effect of the Metal Incorporation Order

AbstractThe effect of the metal incorporation order used in the preparation of bimetallic ultrastable Y (USY) zeolite catalysts for CO2 methanation has been studied. First, a Na‐USY(3) zeolite was impregnated with 5 % of Ni and 3 % of Ce in three ways: Ni before Ce (Ce/Ni), Ce before Ni (Ni/Ce), and co‐impregnation (Ni‐Ce). Stronger interactions between Ni and Ce species are established when Ni is incorporated after or simultaneously with Ce, enhancing the reducibility of the Ni species and decreasing the Ni0 average size to approximately 2.5 nm. However, the CO2 adsorption capacity is smaller for the sample in which Ce is incorporated before Ni. Even though larger Ni0 particles (13.3 nm) are formed when Ni is impregnated first, a good CO2 adsorption capacity was also observed for this sample. Co impregnation was finally found as the best preparation method, the results being confirmed for an optimized USY catalyst in terms of Ni content, Si/Al ratio, and compensating cation.

Carbon Hollow Fiber‐Supported Metal–Organic Framework Composites for Gas Adsorption

AbstractSupporting metal–organic frameworks (MOFs) on scalable contactors such as hollow fibers provides a practical way to expedite their use in large‐scale industrial applications. Here, the development of carbon‐hollow‐fiber‐supported MOFs as adsorbent composites for gas separation processes is reported. Moreover, this work provides an effective approach for the growth of MOFs on the surface of carbon hollow fibers that are successfully produced by pyrolysis of cross‐linked Torlon hollow fibers. To fabricate MOF/carbon composites, the carbon hollow fibers are functionalized in different media to increase the surface hydroxyl groups prior to MOF growth. The MOF incorporation is performed by growing MOF‐74 and UTSA‐16 in the pores and on the outer surface of hollow fibers using dip‐coating and layer‐by‐layer techniques. The MOF/carbon composites with relatively high MOF loadings (37–38 %) and porous structures are successfully fabricated, yielding film thicknesses as high as 10–15 μm. The MOF‐74/carbon and UTSA‐16/carbon composites exhibit surface areas of 266 and 211 m2 g−1, and pore volumes of 0.28 and 0.20 cm3 g−1, respectively. As a proof‐of‐concept, the CO2 adsorption performances are evaluated and the MOF/carbon composites are shown to have relatively good CO2 adsorption capacities of 2.0 and 1.2 mmol g−1 for UTSA‐16 and MOF‐74, respectively, at room temperature and 1 bar.

Waste wool derived nitrogen-doped hierarchical porous carbon for selective CO2 capture.

The goal of this research is to develop a low-cost porous carbon adsorbent for selective CO2 capture. To obtain advanced adsorbents, it is critical to understand the synergetic effect of textural characteristics and surface functionality of the adsorbents for CO2 capture performance. Herein, we report a sustainable and scalable bio-inspired fabrication of nitrogen-doped hierarchical porous carbon by employing KOH chemical activation of waste wool. The optimal sample possesses a large surface area and a hierarchical porous structure, and exhibits good CO2 adsorption capacities of 2.78 mmol g−1 and 3.72 mmol g−1 at 25 °C and 0 °C, respectively, under 1 bar. Additionally, this sample also displays a moderate CO2/N2 selectivity, an appropriate CO2 isosteric heat of adsorption and a stable cyclic ability. These multiple advantages combined with the low-cost of the raw material demonstrate that this sample is an excellent candidate as an adsorbent for CO2 capture.

Effect of Pore Size on the Carbon Dioxide Adsorption Behavior of Porous Liquids Based on Hollow Silica.

Porous liquids are an expanding class of material that has huge potential in gas separation and gas adsorption. Pore size has a dramatic influence on the gas adsorption of porous liquids. In this article, we chose hollow silica nanoparticles as cores, 3-(trihydroxysilyl)-1-propanesulfonic acid (SIT) as corona, and inexpensive industrial reagent polyether amine (M2070) as canopy to obtain a new type of porous liquids. Hollow silica nanospheres with different pore sizes were chosen to investigate the influence of porosity size on CO2 adsorption capacity of porous liquids. Their chemical structure, morphology, thermal behavior and possible adsorption mechanism are discussed in detail. It was proved that with similar grafting density, porous liquid that has bigger pore size possesses a better CO2 adsorption capacity (2.182 mmol g-1 under 2.5 MPa at 298 K). More than that, this article demonstrates a more facile and low-cost method to obtain porous liquids with good CO2 adsorption capacity, recyclability, and huge variability.

Liquefaction of oil palm empty fruit bunch using sub- and supercritical tetralin, n-dodecane, and their mixture

The direct thermochemical liquefaction of oil palm empty fruit bunch (EFB) was performed using sub- and supercritical solvents. The total feedstock conversion at 400°C in tetralin reached 91.8%, and 97.1% with the addition of Fe3O4 and H2. Increasing the reaction temperature to 450°C with n-dodecane present led to a slight increase in the total feedstock conversion. At 400 and 450°C in n-dodecane, the liquefaction reaction afforded almost identical feedstock conversions (>77%) and high liquid product yields; however, the reaction pressure exceeded 10MPa. The variations of the reaction performance in the n-dodecane/tetralin mixture were correlated to the quantity of tetralin. Tetralin was an ideal solvent that promoted an efficient EFB liquefaction process and suppressed char formation. The solid residues collected after the liquefaction reaction were thermally activated, and some of them showed good CO2 adsorption capacity when compared to activated carbons.

Cadmium Metal–Organic Frameworks Based on Ditopic Triazamacrocyclic Linkers: Unusual Structural Features and Selective CO2 Capture

Two three-dimensional cadmium metal–organic frameworks with general formula [Cd2(L1)(H2O)3](NO3)0.7(HCOO)0.2Br0.1 (Cd2L1, L1 = 1,4,7-tris(4-carboxybenzyl)-1,4,7-triazacyclononane) and Cd(HL2)(H2O)2 (CdL2, L2 = 1,4,7-tris(3-(4-benzoate)prop-2-yn-1-yl)-1,4,7-triazacyclononane) based on 1,4,7-triazacyclononane N-functionalized by different arylcarboxylic acids were prepared under solvothermal conditions and characterized by single crystal X-ray analysis and porosity measurements. The crystal structure of Cd2L1 reveals a cationic net with a bcs topology, and nodes are constituted by dinuclear cadmium complexes, in which each cadmium atom adopts a hexacoordinated environment involving both the carboxylate and the cyclic amine. In contrast, CdL2 displays a 2-fold interpenetrated structure with a pcu topology. In this net, the node is a mononuclear complex in which the Cd atom exhibits a seven-coordination geometry. Both materials show a high permanent porosity and good CO2 adsorption properties with a high selectivity over N2 and CH4. The adsorption capacity and selectivity for CO2 were calculated from a multisite Langmuir isotherm model and the ideal adsorbed solution theory, which gave insights into the nature of solid–gas interactions and showed the influence of interpenetration or polarity of the charged framework on their adsorption properties.

Synthesis of MIL-101@g-C3N4 nanocomposite for enhanced adsorption capacity towards CO2

MIL-101@g-C3N4 nanocomposite was prepared by solvothermal synthesis and used for CO2 adsorption. The parent materials (MIL-101 and g-C3N4) and the MIL-101@g-C3N4 were characterized by X-ray diffraction, argon adsorption/desorption, Fourier transform infrared spectroscopy, thermal analysis (TG/DTA), transmission electronic microscopy, and Energy-dispersive X-ray spectroscopy. The results confirmed the formation of well-defined MIL-101@g-C3N4 with interesting surface area and pore volume. Furthermore, both MIL-101 and MIL-101@g-C3N4 were accomplished in carbon dioxide capture at different temperatures (280, 288, 273 and 298 K) at lower pressure. The adsorption isotherms show that the nanocomposite has a good CO2 adsorption affinity compared to MIL-101. The best adsorption capacity is about 1.6 mmol g−1 obtained for the nanocomposite material which is two times higher than that of MIL-101, indicating strong interactions between CO2 and MIL-101@g-C3N4. This difference in efficacy is mainly due to the presence of the amine groups dispersed in the nanocomposite. Finally, we have developed a simple route for the preparation of an effective and new adsorbent for the removal of CO2, which can be used as an excellent candidate for gas storage, catalysis, and adsorption.

Soluble Polymers with Intrinsic Porosity for Flue Gas Purification and Natural Gas Upgrading.

A soluble polymer with intrinsic microporosity, 2,4-diamino-1,3,5-triazine-functionalized organic polymer, is used for the first time as a solid adsorbent, providing an easy solution to overcome the fouling issue. Promising adsorption performances including good CO2 adsorption capacity, excellent CO2 /N2 and CO2 /CH4 selectivities, high chemical and thermal stabilities, and easiness of preparation and regeneration are shown.

Triazine‐Based Porous Organic Polymer with Good CO2 Gas Adsorption Properties and an Efficient Organocatalyst for the One‐Pot Multicomponent Condensation Reaction

AbstractA new porous organic polymer PDVBTT‐1 (poly‐divinylbenzene‐co‐triallyloxytriazine) has been synthesized through radical co‐polymerization utilizing two monomers, that is, divinylbenzene and 2,4,6‐triallyloxy‐1,3,5‐triazine in the presence of AIBN (azobisisobutyronitrile) as a radical initiator under solvothermal conditions in the absence of any structure directing agent. The polymer has been characterized thoroughly by N2 sorption, FTIR, UV/Vis, and solid‐state 13C cross‐polarization magic angle spinning (CP MAS) NMR spectroscopy, field emission FE‐SEM, high‐resolution HR‐TEM, and thermogravimetric/differential thermal analysis (TG/DTA). Owing to the considerably good surface area of 644 m2 g−1 and surface basic sites (1.10 mmol g−1), the material showed very good CO2 adsorption properties. Furthermore, the porous polymer showed good catalytic activity in the base‐catalyzed, one‐pot, multicomponent condensation reaction between various substituted aromatic aldehydes, malononitrile, and activated phenols such as 2‐naphthol, resorcinol, etc., for the synthesis of 2‐amino‐chromenes in water and under solvent‐free microwave irradiation conditions. This N‐rich porous polymer is highly recyclable and thus it has potential for a wide range of base‐catalyzed organic transformations in the future.

Developing microporosity in Kevlar®-derived carbon fibers by CO2 activation for CO2 adsorption

A series of activated carbon fibers (CFs) has been prepared from Kevlar® by carbonization and subsequent CO2 activation. The resulting materials exhibited the specific surface areas in the range of 50–1240m2/g, total pore volumes in the range of 0.02–0.61cm3/g, and micropore volumes in the range of 0.02–0.54cm3/g. The well–developed microporous structure resulted in very good CO2 adsorption properties; the best uptake was 6.58mmol/g of CO2 (at 0°C and p=800mmHg). The CO2 activated Kevlar®-derived CFs achieved better CO2 uptakes than analogous carbons activated in KOH, but the latter outperformed them in benzene adsorption. We concluded that almost exclusively ultramicroporous (w<1nm) CO2-activated CFs adsorbed more CO2 due to the presence of small micropores, whereas the KOH-activated carbons possessed larger micropores, which are essential for adsorption of benzene and related molecules. An additional advantage of the CO2 activated Kevlar®-derived CFs is the preservation of fiber morphology, which can be destroyed during KOH activation.

The oxidation of viscose fiber optimized by response surface methodology and its further amination with PEI for CO2 adsorption

Viscose fiber was oxidized with sodium periodate to prepare a reactive dialdehyde viscose fiber (DAVF) containing abundant aldehyde groups. A solid amine adsorbent (DAVF-PEI) with high amino density for CO2 capture was then prepared by modifying DAVF with polyethylenimine (PEI). Response surface methodology (RSM) based on a three-level, three-factorial design was used to optimize the synthesis conditions of DAVF, in which multiple linear regression equations of aldehyde content and fiber mass loss degree were constructed. The well-designed DAVF was then employed as a support to graft with PEI via Schiff base reaction to prepare a solid amine fiber (DAVF-PEI) for CO2 adsorption. The experimental results verified that DAVF-PEI possessed good thermo-stability and high CO2 adsorption capacity (4.11 mmol/g). DAVF-PEI also showed promising regeneration performance, which could maintain almost the same adsorption capacity for CO2 after ten adsorption and desorption recycles.

Sustainable hierarchical porous carbon aerogel from cellulose for high-performance supercapacitor and CO2 capture

Fabrication of cost-effective and eco-friendly hierarchical porous carbons from the most abundant and widely available biomass cellulose represents a critical and sustainable way to solve the crisis of fossil resources. In this work, a hierarchical porous carbon aerogel with desirable macropores, mesopores, and micropores was obtained via dissolving-gelling and subsequent carbonizing-activating process. The CO2 activated carbon aerogel had a high specific surface area of 1364m2/g and a high specific capacitance of 328Fg−1 (0.5Ag−1, 1.0M H2SO4) as well as an outstanding cycling stability with 96% of the capacitance retention after 5000 charge/discharge cycles. More importantly, for the first time, we demonstrated that the cellulose-derived hierarchical porous carbon aerogel showed a good CO2 adsorption capacity of 3.42mmol/g (at 1atm and 298K), which indicates the possibility of using this carbon aerogel for CO2 capture.

Additive-assisted solvothermal synthesis and properties of porous coordination polymer MOF-14 crystals with controlled morphology and size

Meta-organic frameworks (MOFs) or porous coordination polymers (PCPs), which can be constructed by assembly of organic linkers with metal ions or metal clusters, are an important type of crystalline microporous materials and have attracted considerable attention in the past two decades due to their tailored pore structures, high surface areas and interesting properties such as gas adsorption, storage and separation, catalysis, molecular or ionic sensing as well as drug release. Nowadays remarkable research efforts have focused on bulk MOFs, however, for some applications the crystal size and morphology are also very important. In comparison with bulk materials, nanostructured MOFs may exhibit unique shape- and size-dependent properties, and also have superior properties than the bulk MOFs. However, due to the variety of MOFs structures and the poor understanding of the growth processes of MOFs, the controllable synthesis of nanostructured MOFs still remains a challenge. Therefore, developing efficient synthetic strategies for the tailored fabrication of well-defined nanostructured MOFs materials is highly desirable. In this paper, MOF-14 [Cu3(BTB)2] (H3BTB=4,4′,4″-benzene-1,3,5-triyl-tribenzoic acid) micro/nanocrystals with controllable morphology and size were successfully obtained by additive-assisted solvothermal method. The as-obtained products were characterized by powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and gas adsorption measurements. Acetic acid and sodium acetate were employed in the reaction system as additives, and found to play an important role in determining the crystal morphology and size. With the amount of acetic acid increased, an evolution of particle morphology from cube, truncated rhombic dodecahedron, to rhombic dodecahedron was observed. Meanwhile, the particle size increased gradually. With the amount of sodium acetate increased, the particle morphology of MOF-14 crystals changed from cube to sphere, and the particle size decreased gradually. Moreover, the role of acetic acid and sodium acetate were explored in detail, and a general mechanism for the formation of MOF-14 crystals was proposed. The results of gas sorption measurements reveal that all the MOF-14 crystals with different morphology and size have large Langmuir surface area, good CO2 capture capacity and adsorption selectivity for CO2 over N2. The sorption profiles of the MOF-14 crystals were found to be dependent on the crystal morphology and size. Furthermore, microporous MOF-14 crystals prepared with sodium acetate have additional mesopores, which may supply a new method to expand the porous MOFs.

Organic Amine-Mediated Synthesis of Polymer and Carbon Microspheres: Mechanism Insight and Energy-Related Applications.

A general organic amine-mediated synthesis of polymer microspheres is developed based on the copolymerization of resorcinol, formaldehyde, and various organic amines at room temperature. Structure formation and evolution of colloidal microspheres in the presence of polyethylenimine are monitored by dynamic light scattering measurements. It is found that the colloidal clusters are formed instantaneously and then experience an anomalous shrinkage-growth process. This should be caused by two different reaction pathways: cross-linking inside the microspheres and step-growth polymerization of substituted resorcinol on the microsphere surface, leading to the formation of core-shell heterogeneous structures as confirmed by TEM observation and XPS analysis. A formation mechanism of polymer microspheres is provided based on the aggregation of polyethylenimine/resorcinol-formaldehyde (PEI-RF) self-assembled nuclei, which is apparently different from the conventional Stöber process. Furthermore, nitrogen-doped carbon microspheres are prepared by the direct carbonization of these polymer microspheres, which exhibit microporous BET surface areas of 400-500 m(2) g(-1), high nitrogen contents of 5-6 wt %, and a good CO2 adsorption capacity up to 3.6 mmol g(-1) at 0 °C. KOH activation is further employed to develop the porous texture of carbon microspheres without sacrificing the spherical morphology. The resultant activated carbon microspheres exhibit small particle size (<80 nm), high BET surface areas of 1500-2000 m(2) g(-1), and considerable nitrogen content of 2.2-2.0 wt %. When used as the electrode materials for supercapacitors, these activated carbon microspheres demonstrate a high capacitance up to 240 F g(-1), an unprecedented rate performance and good cycling performance.

Controllable synthesis of few-layered and hierarchically porous boron nitride nanosheets.

Few-layered porous boron nitride nanosheets (BNNS) have been prepared using a dynamic magnesium diboride (MgB2) template and ammonium chloride (NH4Cl) etchant. Magnesium-based intermediates serve as layer separators in the synthesis and prevent extensive aggregation, resulting in few-layered BNNS. The resultant BNNS are hierarchically porous and show good CO2/N2 adsorption selectivity.