Adsorbents For Carbon Dioxide Capture Research Articles

Mind the Gap: The Role of Mass Transfer in Shaped Nanoporous Adsorbents for Carbon Dioxide Capture.

Adsorptive separations by nanoporous materials are major industrial processes. The industrial importance of solid adsorbents is only expected to grow due to the increased focus on carbon dioxide capture technology and energy-efficient separations. To evaluate the performance of an adsorbent and design a separation process, the adsorption thermodynamics and kinetics must be known. However, although diffusion kinetics determine the maximum production rate in any adsorption-based separation, this aspect has received less attention due to the challenges associated with conducting diffusion measurements. These challenges are exacerbated in the study of shaped adsorbents due to the presence of porosity at different length scales. As a result, adsorbent selection typically relies mainly on adsorption properties at equilibrium, i.e., uptake capacity, selectivity and adsorption enthalpy. In this Perspective, based on an extensive literature review on mass transfer of CO2 in nanoporous adsorbents, we discuss the importance and limitations of measuring diffusion in nanoporous materials, from the powder form to the adsorption bed, considering the nature of the process, i.e., equilibrium-based or kinetic-based separations. By highlighting the lack of and discrepancies between published diffusivity data in the context of CO2 capture, we discuss future challenges and opportunities in studying mass transfer across scales in adsorption-based separations.

Mesoporous silica supported ionic liquid materials with high efficacy for CO2 adsorption studies

CO2 capture from industrial processes and power plants, contribute to curbing global warming and advancing sustainability efforts. This study involves the design and synthesis of novel mesoporous silica supported ionic liquid based adsorbents for carbon dioxide capture. Utilization of MSILs delves into the efficiency and mechanisms of CO2 adsorption, offering insights for sustainable carbon capture technologies in combating greenhouse gas emissions. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate and 1-ethyl-3-methylimidazolium methylsulfate ionic liquids were anchored on the surface of mesoporous silica which then led to highly efficient adsorbent material. Simple, efficient and cost saving methodology was performed to synthesize such highly efficient CO2 adsorbent materials. In addition, we theoretically predicted the favorable interaction mechanism of chosen molecular entities for CO2 adsorption using density functional theory (DFT) analysis. Theoretical results depict the strong interaction of molecular entities with CO2 gas molecules which is clearly evident from the experimental findings.

Activated carbon fibers from recycled acrylic and cotton for carbon dioxide capture

AbstractIn this study, activated carbon fibers (ACFs) were produced from mechanically recycled acrylic (PAN) and cotton (CO) fibers and their blend (PAN/CO) in felt form as an adsorbent for carbon dioxide capture. For this purpose, stabilization, carbonization, and chemical activation processes were applied consecutively. The effects of recycled fiber type, carbonization temperature, and activation agent impregnation ratio were investigated. The resultant ACFs were characterized by elemental analysis, SEM, FTIR, XPS, and BET analyses, and carbon dioxide adsorption capacity was tested. It was observed that the fibrous structure of all samples was preserved at all stages, although the fiber diameters were reduced. The maximum quantity of adsorbed CO2 was found to be 3.79, 3.47, and 3.28 mmol CO2/g for recycled PAN, CO, and PAN/CO based samples, respectively, at 298 K at a relative pressure of 0.989. It was conducted that the carbon dioxide adsorption performance was affected by both the ACF surface area and the nitrogen content in the structure. It was concluded that recycled fiber‐based ACFs as CO2 adsorbents could be successfully produced with reasonable adsorption performance as a sustainable alternative.Highlights Activated carbon fibers were produced from recycled acrylic and cotton fibers Fibrous structure was preserved, but fiber diameters decreased Reasonable carbon dioxide adsorption capacity was attained Recycled fiber‐based ACFs could be a sustainable alternative to CO2 adsorbents

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

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

Solution-reprocessable polymers of intrinsic microporosity as adsorbents for carbon dioxide capture

Anthropogenic carbon dioxide emission has been an urgent environmental and climate issue, yet remains a challenge to address. Solid adsorbents are potential candidates for CO2 capture while their insolubility nature makes the regeneration problematic when fouled. Here we report the synthesis of a thioamide incorporated polymer of intrinsic microporosity, TPIM, which features high intrinsic microporosity with specific surface areas of 531 m2/g, and good solubility in selected organic solvents such as THF, DMSO and DMAc. Static physisorption and kinetic breakthrough experiments revealed several promising features of TPIM: high CO2 capacity of 2.45 mmol/g at 1 bar and 298 K, good CO2/N2 mixture dynamic separation performance, and facile regeneration ability. Most interestingly, its porosity and CO2 capacity could be easily restored through a simple dissolution-separation-precipitation (DSP) approach, making it regenerative when fouled, providing a new insight for the future design of regenerable adsorbents.

High-value utilization of lignin to prepare N,O-codoped porous carbon as a high-performance adsorbent for carbon dioxide capture

The concern for environmental sustainability has increased the interest in biomass materials for the synthesis of porous carbon, especially as an effective alternative and multifunctional adsorbent in the field of adsorption of a wide range of pollutants and carbon dioxide. Lignin has high carbon content, abundant aromatic rings and condensation bonds, which make it suitable as a precursor for carbon-containing materials. In this study, lignin was firstly precarbonized to achieve its degradation and efficient conversion, and then chemically activated by KOH to prepare a low-cost porous carbon materials with finely developed microporous structure, which showed excellent gas adsorption performance of 3.98 and 5.82 mmol/g at 1 bar, 298 K and 273 K, respectively. In addition to this, we have also investigated the dynamic sorption properties of the samples on CO2. The original lignin contains N,O functional groups that can be doped to the surface of the porous carbon, and previous studies have confirmed that the porosity and functional groups on the surface of the carbon material play a positive role in improving the defective and adsorption properties of the material. Our work provided a promising strategy for valorization of lignin as a precursor for producing advanced carbon materials.

Epoxy-functionalized polyethyleneimine modified epichlorohydrin-cross-linked cellulose aerogel as adsorbents for carbon dioxide capture

Developing affordable and effective carbon dioxide (CO2) capture technology has attracted substantial intense attention due to the continued growth of global CO2 emissions. The low-cost and biodegradable cellulosic materials are developed into CO2 adsorbent recently. Epoxy-functionalized polyethyleneimine modified epichlorohydrin-cross-linked cellulose aerogel (EBPCa) was synthesized from alkaline cellulose solution, epoxy-functionalized polyethyleneimine (EB-PEI), and epichlorohydrin (ECH) through the freezing-thawing processes and freeze-drying. The Fourier transform infrared spectroscopy confirmed that the cellulose aerogel was successfully modified by EB-PEI. The X-ray photoelectron spectroscopy analyses confirmed the presence of N 1s and Cl 2p in EBPCa, meaning that the chlorine of ECH and the amino groups of EB-PEI exist in the cellulose surface. The obtained sample has a rich porous structure with a specific surface area in the range of 97.5–149.5 m2/g. Owing to its uniformly three-dimensional porous structure, the sample present preferable rigidity and carrying capacity, which 1 g of sample could easily carry the weight of a 3000 ml Erlenmeyer flask filled with water (total 4 kg). The sample showed good adsorption performance, with a maximum adsorption capacity of 6.45 mmol/g. This adsorbent has broad prospects in the CO2 capture process.

Selective carbon-based adsorbents for carbon dioxide capture from mixed gas streams and catalytic hydrogenation of CO2 into renewable energy source: A review

The rise in the temperature contributing to global warming is attributed to the increased human-generated greenhouse gas emission in the ambient atmosphere. In this paper, firstly, a comprehensive overview of the capture technologies is presented, highlighting the post-combustion capture technology as one of the promising CO2 mitigation strategies. The performance of activated carbon, amine-functionalized and metal-oxide impregnated materials prepared from renewable precursors as the acknowledged adsorbents are well assessed and presented systematically. Conversion of CO2 is proposed as a sustainable practice to substitute for dwindling fossil fuels. A strong emphasis is put on the conversion of CO2 into value-added chemicals like higher hydrocarbons via series of catalytic-hydrogenation reactions. The specific aim of this study is to assist researchers by providing a holistic overview of different aspects of carbon-based adsorbents for post-combustion capture instead of the current-state-of art technology and enhancing the pathways for CO2 valorization to clean and renewable end-products.

A Process for Carbon Dioxide Capture Using Schiff Bases Containing a Trimethoprim Unit

Environmental problems associated with the growing levels of carbon dioxide in the atmosphere due to the burning of fossil fuels to satisfy the high demand for energy are a pressing concern. Therefore, the design of new materials for carbon dioxide storage has received increasing research attention. In this work, we report the synthesis of three new Schiff bases containing a trimethoprim unit and the investigation of their application as adsorbents for carbon dioxide capture. The reaction of trimethoprim and aromatic aldehydes in acid medium gave the corresponding Schiff bases in 83%–87% yields. The Schiff bases exhibited surface areas ranging from 4.15 to 20.33 m2/g, pore volumes of 0.0036–0.0086 cm3/g, and average pore diameters of 6.64–1.4 nm. An excellent carbon dioxide uptake (27–46 wt%) was achieved at high temperature and pressure (313 K and 40 bar, respectively) using the Schiff bases. The 3-hydroxyphenyl-substituted Schiff base, which exhibited a meta-arrangement, provided the highest carbon dioxide uptake (46 wt%) due to its higher surface area, pore volume, and pore diameter compared with the other two derivatives with a para-arrangement.

Developing Eco-Friendly and Cost-Effective Porous Adsorbent for Carbon Dioxide Capture.

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO2). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO2 capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO2 capture performance, with equilibrium adsorption of 2.3 mmol CO2/g at 0 °C and 1 bar for at a surface area 675.62 m2/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO2 capture and possible subsequent electrochemical conversion.

Sepiolite-based adsorbents for carbon dioxide capture

Abstract Sepiolite and the sepiolite-based materials were studied in terms of carbon dioxide adsorption. The pore structure and the surface characterization of the obtained materials were specified based on adsorption-desorption isotherms of nitrogen measured at –196oC and carbon dioxide at 0oC. The specific surface area (SSA) was calculated according to the BET equation. The pore volume was estimated using the DFT method. Pristine sepiolite has shown the following value of SSA and CO2 uptake at 0oC – 105 m2/g and 0.27 mmol/g, respectively. The highest value of these parameters was found for material obtained by KOH activation of mixture sepiolite and molasses (MSEP2) – 676 m2/g and 1.49 mmol/g. Sample MSEP2 also indicated the highest value of total pore volume and micropores volume with a diameter up to 0.8 nm.

The latest development on amine functionalized solid adsorbents for post-combustion CO2 capture: Analysis review

• Recent advances amine functionalized solid adsorbent for CO 2 capture are reviewed. • Solid amine adsorbents fabrication and modification route towards is emphasized. • Amine functionalized solid materials from the waste as competitive adsorbents. • Improved stability of solid amine adsorbents for CO 2 capture is analyzed. Global warming and associated global climate change have led to serious efforts towards reducing CO 2 emissions through the CO 2 capture from the major emission sources. CO 2 capture using the amine functionalized adsorbents is regard as a direct and effective way to reducing CO 2 emissions due to their large CO 2 adsorption amount, excellent CO 2 adsorption selectivity and lower energy requirements for adsorbent regeneration. Moreover, large number of achievements on the amine functionalized solid adsorbent have been recorded for the enhanced CO 2 capture in the past few years. In view of this, we review and analyze the recent advances in amine functionalized solid adsorbents prepared with different supporting materials including mesoporous silica, zeolite, porous carbon materials, metal organic frameworks(MOF) and other composite porous materials. In addition, amine functionalized solid adsorbents derived from waste resources are also reviewed because of the large number demand for cost-effective carbon dioxide adsorbents and the processing needs of waste resources. Considering the importance of the stability of the adsorbent in practical applications, advanced research in the capture cycle stability has also been summarized and analyzed. Finally, we summarize the review and offer the recommendations for the development of amine-based solid adsorbents for carbon dioxide capture.

Secondary utilization of the spent fly ashes-derived sorbents

In the years 2017-20, the research on the use of fly ashes and bottom ashes from power plants for the preparation of adsorbents for carbon dioxide capture from flue gases was carried out at the involved institutes. As part of the research, adsorbents were prepared by alkali fusion and hydrothermal processes. The obtained products were subjected to cyclic adsorption and desorption tests simulating their industrial use. One of the partial tasks was to evaluate how the worn adsorbents can be subsequently utilized. In the study presented here, the materials collected after the adsorption testing were subjected to several procedures, which aim was to verify the applicability of these materials as substrates for the reclamation of excavated brown coal and lignite quarries. The basic property assessed was the ability to retain humidity and thus contribute to the water balance in the reclaimed landscape. A hydration test followed by slow drying of the sample in a thermogravimetric analyzer was proposed for this purpose. With regard to the raw materials from which the adsorbents were prepared, attention was also paid to the risk of undesired leaching of toxic substances. The last measured parameter was the course of CO2 desorption from the pores of the used adsorbent. It answers the question of whether the adsorbent is usable for terrain reclamations in the state after the last adsorption (i.e. CO2 saturated), or whether it requires thermal desorption as the final step. Based on the results of hydration tests of the spent adsorbents, it can be concluded that they could be applied in the reclamation of closed lignite quarries, and these materials would allow a more sophisticated application than just as a stabilizer. In the tested samples, the high retention of water and its slow release was confirmed by the TGA method, which (in the case of the mentioned use) could improve the management of soil humidity and its distribution to woody plants used in the biotechnical reclamation phase. Another, but as yet unproven, possibility is to use the porous structure of the materials as a suitable substrate for colonization by nitrifying bacteria. These bacteria would subsequently improve the self-cleaning ability of the water tank created in the case of the hydraulic reclamation method. Due to the results of measurements of carbon dioxide desorption from saturated adsorbents, it is necessary to recommend that thermal desorption should be included in their preparation before the use in reclamation. Tests of toxic elements leaching have not identified any potential risk from their mobilization into groundwater or surface water.

Efficacies of Carbon-Based Adsorbents for Carbon Dioxide Capture

Carbon dioxide (CO2), a major greenhouse gas, capture has recently become a crucial technological solution to reduce atmospheric emissions from fossil fuel burning. Thereafter, many efforts have been put forwarded to reduce the burden on climate change by capturing and separating CO2, especially from larger power plants and from the air through the utilization of different technologies (e.g., membrane, absorption, microbial, cryogenic, chemical looping, and so on). Those technologies have often suffered from high operating costs and huge energy consumption. On the right side, physical process, such as adsorption, is a cost-effective process, which has been widely used to adsorb different contaminants, including CO2. Henceforth, this review covered the overall efficacies of CO2 adsorption from air at 196 K to 343 K and different pressures by the carbon-based materials (CBMs). Subsequently, we also addressed the associated challenges and future opportunities for CBMs. According to this review, the efficacies of various CBMs for CO2 adsorption have followed the order of carbon nanomaterials (i.e., graphene, graphene oxides, carbon nanotubes, and their composites) < mesoporous -microporous or hierarchical porous carbons < biochar and activated biochar < activated carbons.

A novel blended amine functionalized porous silica adsorbent for carbon dioxide capture

In order to accomplish efficient CO2 capture, poly(ethyleneimine) (PEI) and tetraethylenepentamine (TEPA), with commonly used and inexpensive, was codispersed into the as-prepared SBA-15 (SBA-15(p)) to prepared blended amine functionalized adsorbent. The influence of the mass ratio of PEI to TEPA on the adsorption property was investigated. The promoting effects of TEPA on CO2 capture property were investigated. The adsorbents were characterized using N2 adsorption/desorption, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and in situ diffuse reflectance infrared fourier transform spectroscopy (in situ DRIFTS). Among the prepared adsorbents, the SBA-15(p) with 30 wt% PEI and 40 wt% TEPA has the CO2 capture capacity of 4.64 mmol/g and the optimal amine efficiency (0.359 molCO2/molN) at 75 °C with 20 vol% CO2 in N2. The addition of TEPA species could improve the CO2 adsorption amount with high amine utilization. The P123 with wheel-like distribution in SBA-15(p) promotes the CO2 capture by optimizing the accessibility of amine to the CO2. After 15 adsorption cycles, the SBA-15(p) with 40 wt% PEI and 30 wt% TEPA has better reusability and cyclic performance, the adsorption capacity can keep around 4.13 mmol/g. The result indicated that more PEI in the adsorbent would improve the adsorbent cyclic stability. Meanwhile, the in-situ DRIFTS results suggested that the reaction of CO2 molecule with the amine active sites in the adsorbent, agrees with anionic and cationic mechanisms.

Synthesis and characterization of coconut pith char adsorbents for carbon dioxide capture

The emission of carbon dioxide (CO 2 ) from anthropogenic sources has become a public concern. Several effective and affordable post combustion CO 2 capture technology has been reported and one of the approaches is through adsorption process. This study focused the adsorption onto low-cost adsorbent that can be produced from waste biomass through carbonization method. Coconut pith (CP) was used as precursor and carbonized at temperature of 300 and 700oC under ambient condition. The chemical and physical properties showed that the surface area, pore volume, ash, moisture and carbon content of chars increased, while the yield content decreased with increasing carbonization temperatures. The char adsorbent carbonized at higher temperature (CP700) showed the better performance with CO 2 adsorption capacity of 10.00 mmol/g at 25oC. It was revealed that carbonization temperature greatly affects the properties of CP, hence influence the ability of the adsorbent to capture the CO 2 . Hence, these unique properties and adsorption performance showed that char adsorbent enable to be used as an effective adsorbent for CO 2 capture and thus improving environmental quality and sustainability.

Adsorption of CO2 gas on graphene–polymer composites

Three-dimensional graphene-polymer porous materials have been proposed recently as potential adsorbents for carbon dioxide capture. We report results from molecular dynamics simulations on the adsorption of CO2 gas by composite systems formed by six different types of polymers. All composites are characterized by a constant polymer-to-graphene mass-ratio of 1.02 and their capture capacity as a function of the gas pressure is analyzed relative to the adsorption of nitrogen and methane. The results were then compared to the performance obtained from a bare-graphene sheet. More specifically, we examined the abilities of hydrogen-bond donor groups, amines and amides, as well as aromatic rings to promote and discriminate CO2 capture. We find that bare-graphene displays the highest capacity to adsorb CO2. Nevertheless, increasing the number of amine/amide protic groups of the polymer augments the adsorption. In fact, the best performing polymer in our study, which contains three protic groups per monomer, exhibits capture of CO2 almost as good as bare-graphene. Furthermore, these protic polymers form substantial intra-polymer hydrogen bonds and consequently exhibit cohesive behavior. In these cases, the aggregation of the polymer resulted in partial exposure of the graphene sheet on which the gas can adsorb as well. In contrast aprotic polymers, such as poly(styrene) or poly(methyl-methacrylate), spread extensively on graphene and are characterized by small capacities to adsorb CO2. For all systems studied, CO2 is adsorbed preferentially relative to N2 and CH4. This preferential adsorption is almost constant as a function of the gas pressure with values ranging from 2 to 12.

Generation and use of a pure titanium pillared MCM-36 structure as a high efficiency carbon dioxide capture platform and amine loaded solid adsorbent

Abstract In this work titanium oxide pillared MCM-36 adsorbents have been studied as amine loaded class-1 adsorbents for carbon dioxide capture. This work has shown that pillaring of the MCM support with titanium oxides can yield a material with carbon dioxide capacities higher than silica pillared MCM sorbents (1.62 mmol/g for Ti, 1.02 mmol/g for Si), with similar surface area (∼450 m2/g for Ti versus ∼500 m2/g for Si) observed for the titanium pillared derivative. The titanium oxide pillared adsorbent was also loaded with polyethylenimine and tetraethylenepentamine amine containing molecules. It was observed that the higher initial capacity of the titanium oxide pillared MCM-36 allows for it to retain good CO2 capacities of up to ∼1.79 mmol/g at high amine loadings (∼50 wt% of tetraethylenepentamine). However, it was found that increasing the content of polyethylenimine loaded on the adsorbent led to decreased carbon dioxide capacities.

A novel amine double functionalized adsorbent for carbon dioxide capture using original mesoporous silica molecular sieves as support

In order to relieve the amine agglomeration phenomenon in solid amine adsorbent and realize the efficient CO2 capture, a novel double-functionalized adsorbent was synthesized by grafting 3-aminopropyltriethoxysilane and impregnating tetraethylenepentamine, using original mesoporous silica molecular sieves as support. The effects of organic amine loading, gas flow rate and adsorption temperature on CO2 adsorption properties of adsorbent were studied. The results show that SBA-15(p)-AP-70T modified with 70% TEPA has the maximum N content (15.81 mmol/g) and the maximum saturated adsorption capacity (5.69 mmol/g) at 75 °C。Moreover, the CO2 adsorption capacity of this adsorbent can still remain about 5.2 mmol/g after 15 adsorption/desorption cycles. It is mainly because that the grafted APTES and residual P123 in the support pore provide space and hydrogen bonding functional groups for TEPA dispersion and fixation, while reduce the loss of TEPA during the cycle process. Therefore, compared with adsorbent modified by only TEPA, the adsorption capacity and stability of this adsorbent can be effectively improved. In addition, kinetic studies indicate that CO2 adsorption on SBA-15(p)-AP-70T is mainly chemisorption. According to the in situ DRIFTS results, CO2 adsorption mechanism on SBA-15(p)-AP-70T adsorbent is consistent with the zwitterion mechanism.

Synthesis of porous carbon monolith adsorbents for carbon dioxide capture: Breakthrough adsorption study

Abstract Carbon monoliths with bimodal porosity were obtained through nanocasting technique from silica monoliths (hard template) and furfuryl alcohol (precursor). These carbon adsorbents were evaluated as sorbents for CO2 capture by using a fixed-bed adsorption set up under dynamic conditions. Carbonization at different temperatures (550 to 950 °C) was carried out that resulted in the generation of different carbon adsorbents containing oxygen functional groups. The textural characterization results reveal the effect of nanocasting technique, which is confirmed from the generation of mesopores (0.41), micropores (0.85 cm3 g−1) and high surface area (1225.1 m2 g−1) of adsorbent synthesized at 950 °C, as shows highest CO2 uptake of 1.0 mmol g−1 at 30 °C and 12.5% CO2 concentration. The increase in the adsorption capacity with increasing CO2 concentration and decrease with the increasing adsorption temperature confirms the physisorption process. Five adsorption–desorption cycles show established materials with excellent regeneration stability as an adsorbent. Furthermore, three kinetic models along with three isotherms were used in the present study to analyze the adsorption data and found that fractional order kinetic model and Temkin isotherm fitted best. Thermodynamic studies suggested the exothermic, spontaneous as well as the feasibile nature of the adsorption process.