This work is concerned with the calculations using eight different isotherm models (Langmuir, Freundlich, Halsey, Temkin, Toth, Sips, Radke-Prausnitz, and Redlich-Peterson) to fit the experimental ...isotherm data of CO2 on activated carbon (AC). Moreover, systematic and comprehensive modeling of non-linearized isotherms was performed by developing an algorithm for determining their parameters and analyzing seven error functions. To determine the best-fitted isotherm model and error function, we used the sum of normalized errors (SNE) procedure. The modeling results obtained showed that the Redlich-Peterson, Radke-Prausnitz, and Toth isotherm models are best suited to the empirical data, with relatively high R2 determination coefficients. Finally, the SNE method allowed the selection of the chi-square test (χ2) and the HYBRID error as universal indicators in nonlinear regression to select the set of optimized isotherm parameters. The interpretation of the assumptions of the isotherm models, which featured a strong correlation with the experimental data, allowed a conclusion to be drawn about the sub-monolayer adsorption mechanism on the heterogeneous surface of the AC. The acquired modeling findings are expected to establish a certain theoretical foundation for the characterization of CO2 adsorption equilibrium studies at the interface between porous solid materials and gases.
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•A detailed mathematical approach to the CO2 adsorption process was examined.•8 nonlinear models of isotherms and 7 different error functions were compared.•Presenting optimization criteria in the application of equilibrium sorption.•Isotherms of Redlich-Peterson, Radke-Prausnitz, Toth had best correlate with the experimental data.•HYBRID and the chi-square test (χ2) were the best of indicators in the prediction of isotherm modeling.
In this paper, we provide a comprehensive review of the latest research trends in terms of the preparation, and characteristics of activated carbons regarding CO
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adsorption applications, with a ...special focus on future investigation paths. The reported current research trends are primarily closely related to the synthesis conditions (carbonization and physical or chemical activation process), to develop the microporosity and surface area, which are the most important factors affecting the effectiveness of adsorption. Furthermore, we emphasized the importance of regeneration techniques as a factor determining the actual technological and economic suitability of a given material for CO
2
capture application. Consequently, this work provides a summary and potential directions for the development of activated carbons (AC). We attempt to create a thorough theoretical foundation for activated carbons while also focusing on identifying and specific statements of the most relevant ongoing research scope that might be advantageous to progress and pursue in the coming years.
Four different nanoshapes of cerium dioxide have been prepared (polycrystals, rods, cubes, and octahedra) and have been decorated with different metals (Ru, Pd, Au, Pt, Cu, and Ni) by incipient ...wetness impregnation (IWI) and ball milling (BM) methods. After an initial analysis based on oxygen consumption from CO2 pulse chemisorption, Ni-like metal, and two forms of CeO2 cubes and rods were selected for further research. Catalysts were characterized using the Brunauer-Emmett-Teller formula (BET), X-ray spectroscopy (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV–visible spectrophotometry (UV-Vis), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H2-TPR) and CO2 pulse chemisorption, and used to reduce of CO2 into CO (CO2 splitting). Adding metals to cerium dioxide enhanced the ability of CeO2 to release oxygen and concomitant reactivity toward the reduction of CO2. The effect of the metal precursor and concentration were evaluated. The highest CO2 splitting value was achieved for 2% Ni/CeO2-rods prepared by ball milling using Ni nitrate (412 µmol/gcat) and the H2 consumption (453.2 µmol/gcat) confirms the good redox ability of this catalyst.
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•new tailored nanoporous carbons from the common polypody for CO2 capture.•superior CO2 adsorption of 9.05 mmol/g at 273 K &1 bar, stability, and selectivity.•N2 flow effect on ...nanoporous carbons properties especially textural and CO2 capture.•CO2 adsorption unchanged after 20 cycles.
The one-step synthesis of new tailored nanoporous carbons (NCs) from the common polypody (Polypodium vulgare) as feedstock for the first time was presented. The significance of nitrogen flow (2.25 – 30 dm3/h) and temperature (500 – 900 °C) during carbonization was investigated. KOH activated NCs have a high specific surface area (1994 m2/g), large total pore volume (0.998 cm3/g), and micropore volume (0.923 cm3/g). NCs displayed tailored textural properties for CO2 capture. The NCs showed superior CO2 adsorption at 1 bar equal to 5.67 and 9.05 mmol/g, for 298 and 273 K, respectively. The selectivity of CO2 adsorption in relation to N2 was also high. The selectivity coefficient was achieved to 23 and SIAST selectivity 59.5. The isosteric heat of adsorption calculated on the basis of the Clausius-Clapeyron equation and Sips model was ranged from 26 to 31 kJ/mol and suggested the physisorption mechanism of adsorption.
Low-cost carbonaceous adsorbents with microporous structures and a moderate specific surface area (up to 1630 m2 g−1) were prepared from different amazonian nutshells by one-step chemical activation ...with KOH for CO2 storage. In-depth micropore structure analysis and surface characterization were performed using adsorption isotherms at 298 K and carbon dioxide isotherms at 273 K. The Brazilian nutshell and Cascara Capuassau exhibit a remarkable CO2 uptake capacity of 5.14 mmol g−1 and 5.13 mmol g−1 at 273 K, respectively up to 1 atm. The highest CO2 adsorption at 298 K equal to 3.67 mmol g−1 was observed on activated carbon produced from Cascara Capuassau. The low-pressure CO2 capacities are well correlated with the volume of small micropores (<0.7 nm) rather than the total micropore volume and surface area. The great mesoporosity of activated carbons is beneficial to ensure higher CO2 capture at high uptake pressure.
•Demonstration of one-step chemical synthesis procedure for activated carbon from biomass.•Characterization studies and several analytical techniques were carried out to determine CO2 sorbent capacity.•Activated carbons from amazonian nutshells represents an interesting alternative to CO2 capture.•The amount of CO2 adsorbed mostly depends on the population of narrow micropores (<1 nm).
In this work, we report the use of activated carbon synthesized from a sustainable material - fern leaves - as a sorbent for carbon dioxide capture applications. The resource-friendly technology for ...activated carbon production was applied and described. The activated carbons were prepared by chemical and physical activation and carbonization at the same time at the temperature range of 500–900 °C. This method reduces energy consumption and resources. KOH and CO2 were used as activating agents. The evaluation of the CO2 adsorption ability of the activated carbon was supported by different methods including: elemental analysis using X-ray fluorescence spectroscopy, ash content, surface area and porosity measurements, Raman spectroscopy, X-ray spectroscopy and scanning electron microscopy. Results indicated that the optimum temperature of the synthesis was 700 °C. The highest achieved adsorption of CO2 was equal to 6.77 mmol/g and 3.58 mmol/g at 0 °C and 25 °C, respectively. The activated carbons synthesized from fern leaves showed high CO2 adsorption and selectivity. Moreover, the abundance and low cost of fern leaves make them very promising carbon sources for CO2 sorbents production.
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•Fern leaves as a sustainable material for porous activated carbon.•Sustainable technology: carbonization, chemical, physical activation at the same time.•Sorbents are characterized and tested for their capture potentials for CO2.•High CO2 adsorption: 6.77 mmol/g at 0 °C and 100 kPa.
Over the last decade, CO2 adsorption technology has quickly gained popularity and is now widely applied in global CCUS projects due to playing an important role in achieving net-zero emissions by ...2050. As a result, new materials, or methods of post-modification of those already available have been successively reported to enhance the efficiency of CO2 capture from flue gases. This paper discusses a systematic understanding of fundamental aspects of current research trends is discussed in terms of developing selected CO2 solid adsorbent materials, with a particular emphasis on the upcoming challenges. The adsorbent candidates are reviewed considering the practical drawbacks of imposed by industrial scale and economics, including carbon-based materials, MOFs, polymers, zeolite, silica, alumina, metal oxides, amine-based adsorbents, and other composite porous materials. Solid sorbents derived from biomass, industrial residues, and their thermochemical conversion are also studied due to the high need for cost-effective raw materials and their crucial role in circular economy. Lastly, a techno-economic analysis (TEA) is included to provide the most important criteria that should be considered when adsorbents are implemented on an industrial scale. Consequently, the review is summarized, and recommendations are offered for future research development of CO2 adsorbent materials. The paper aims to establish a comprehensive and fundamental theoretical basis for the characterization of adsorbent technologies currently used to reduce CO2 emissions, along with highlighting the identification and precise articulation of the most important future research paths that could be beneficial to address over the next years.
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•Focuses on the development of CO2 capture by adsorption with respect to critical limitations and trends.•Discusses opportunities and upcoming challenges of CO2 solid adsorbent materials.•Summarizes current modification strategies and research directions for selected CO2 adsorbent materials.•Concludes the collection of a wide range of up-to-date specific measurements of adsorbents affected by the modifications implemented to improve CO2 capture efficiency.•Provides details of the technical-economic analysis (TEA).
A novel micro-mesoporous activated carbon (SBL AC-700) is synthesized from subabul (Leucaena leucocephala) sawdust waste by direct single-stage physical activation at 700 °C for 1 h for carbon ...capture applications. The synthesized AC is characterized to explore various physiochemical properties like elemental composition, surface morphology and crystallinity, presence of functional groups, surface area, pore size, and pore volume. Additionally, emphasis is given to exploring the thermophysical aspects of the novel AC, the literature regarding which is scarce in the open domain. The CO2 adsorption study is carried out for a 0–1 bar pressure for temperatures ranging from 0 to 75 °C. The analysis revealed that the AC possesses a surface area of 590 m2/g and pore volume and width of 0.27 cm3/g and 1.85 nm, corresponding to a 70% microporosity with a well-developed porous structure. At 25 °C and 1 bar, a CO2 uptake of 40.54 cm3/g is achieved, corresponding to an increment of 6–202% compared to other commercials, chemically and physically activated carbons. Moreover, SBL AC-700 has a thermal conductivity of 0.095 W/m K, 8–131% higher than other benchmarks ACs and much lower specific heat of 0.82 kJ/kg K corresponding to lesser regeneration energy requirements. Experimental data are fitted with various isotherm models, i.e., Langmuir, Freundlich, Sips, R–P, and Toth, out of which R–P and Toth models exhibit the best fit. In continuation, adsorption kinetics is studied to explore the dynamic performance of the SBL AC-700 by using Pseudo-first-order, Pseudo-second-order, Elovich, and intraparticle diffusion kinetic models.
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•AC SBL AC-700 from subabul sawdust waste is synthesized successfully.•Novel AC is prepared by eco-friendly single-step direct CO2 activation.•The ability of CO2 uptake at 25 °C and 1 bar is 40.54 cm3/g.•SBL AC-700 has a thermal conductivity of 0.095 W/m K, 8–131% higher than other ACs.•Isotherm, kinetics, and thermodynamic modeling is done for the AC-CO2 pair.
•A microporous activated carbons were produced from PP waste using KOH.•The optimum activation temperature was determined as 800 °C.•The CO2 uptake reached up to 5.53 and 4.44 mmol/g at 0 and 25 °C, ...respectively.•The activated carbon materials showed a good CO2/N2 adsorption ideal selectivity.
In this work, pomegranate peel (PP), the by-products abundantly available from the fruit processing industries, has been applied as renewable resources for preparation of low cost, eco-friendly and high quality activated carbons. The optimum conditions for the adsorption of carbon dioxide (CO2) by the activated carbons were evaluated by controlling the activation temperature. KOH was used as the activation agent at a KOH/PP activation ratio of 1:1. Four activated carbons were synthesized at activation temperatures in the range 600−900 °C, their surface and pore characteristics along with the CO2 adsorption were examined. The results showed that with the increase in activation temperature from 600 to 800 °C, the total pore volume and specific surface area sharply increased from 0.78 to 1.28 cm3/g and 1311 to 2141 m2/g, respectively. However, the values for both these parameters decreased at temperatures above 900 °C. The best CO2 adsorption capacity of 4.44 mmol/g and 5.53 mmol/g were obtained for the PP-K-800 sample at 25 and 0 °C up to 1 bar, respectively. This result highlights the importance of the structural and textural characteristics of the activated carbon, prepared at different activation temperatures on CO2 adsorption behaviors.
A series of nanoporous activated biocarbons have been successfully obtained from novel carbon precursor - lumpy bracket. The textural properties of the biocarbons were tailored towards microporosity ...suitable for high CO2 adsorption. Outstanding CO2 adsorption up to 1.67 mmol/g at the temperature of 298 K and at the pressure of 0.15 bar was achieved. The performance of biocarbons in the absorption/regeneration cycles towards CO2 adsorption remained stable. The selectivity of CO2 over N2 calculated on the basis of Ideal Adsorbed Solution Theory was excellent (33.9–130.2). To the best to our knowledge, the prepared activated carbon labelled as 850_1 is one of the most promising sorbents tested in CO2 post-combustion capturing and pre-combustion capturing. Furthermore, the electrochemical properties of this sample were also evaluated. The specific capacitance reached over 220 F/g with excellent retention (~92% of the original capacitance) after 5000 cycles. These results clearly indicate that activated carbons obtained from lumpy bracket can be used for the production of low cost and, more importantly, highly efficient electrode in supercapacitors as well. In this way, simple and efficient direct conversion of the lumpy bracket into highly valuable multifunctional system is proposed.
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•Nanoporous activated biocarbons from lumpy bracket•Adsorption of CO2 14.31 mmol/g (30 bar, 273 K)•CO2/N2 adsorption selectivity SIAST = 46.4•Specific capacitance retention 92% after 5000 cycles
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