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The efficient CO2 capture requires engineering a low-cost, highly efficient adsorbent. Herein, the upcycling of waste floral foam into chemically activated nanoporous carbon (CANC) is reported. The implications of the impregnation ratio of KOH on the porosity, surface functionality of CANC, and its role in CO2 capture are examined and discussed. The optimized sample, CANC-2 (SSA 1043 m2/g), with a large ultra-micropore volume and higher oxygen and nitrogen content, demonstrates 3.71 mmol/g CO2 capture capacity at 15 ℃ and 1 atm. The framework provided here offers a technique for tuning the attributes of nanoporous carbon favorable for CO2 capture. Ultimately, the pollution control of solid polymeric waste can be done by upcycling it into value-added products which further utilized in environmental applications.

Abstract This article presents the unique research results of the comprehensive analysis of the porous structure of activated carbons obtained from biomass waste materials from the wood industry during activation in an air atmosphere. The porous structure was analysed on the basis of nitrogen and argon adsorption isotherms via complementary multi-method analysis, i.e. the new numerical clustering-based adsorption analysis, the non-local density functional theory and the quenched solid density functional theory methods. The analytical results for the prepared activated carbons were compared with analogous results obtained for commercial activated carbon. On the basis of the conducted studies it has been determined that the new numerical clustering-based adsorption analysis method gives credible and valuable information on the textural properties of activated carbons which are in strict correlation and mutually complement with the results of the analysis with the use of the quenched solid density functional theory method. The research results obtained in this paper, it has also been shown that from waste materials of the wood industry, in a relatively cheap and cleaner production process, it is possible not only to obtain carbonaceous materials almost comparable to commercial activated carbon, but also to manage the waste in accordance with the principles of a closed-loop economy and sustainable development. The paper pays also attention to the often overlooked economic and ecological aspects, which should nevertheless be taken into account when comparing different adsorbents, rather than their textural properties alone.

Abstract This paper presents the results of an analysis of the porous structure of spherical activated carbons obtained from cation-exchange resin beads subjected to ion exchange prior to activation. The study investigated the effects of the type of cation exchange resin, the concentration of potassium cations in the resin beads and the temperature of the activation process on the adsorption properties of the resulting spherical activated carbons. The numerical clustering-based adsorption analysis method and the quenched solid density functional theory were used to analyse the porous structure of spherical activated carbons. Based on original calculations and unique analyses, complex relationships between preparation conditions and the porous structure properties of the obtained spherical activated carbons were demonstrated. The results of the study indicated the need for simultaneous analyses using advanced methods for the analysis of porous structures, i.e., the numerical clustering-based adsorption analysis method and the quenched solid density functional theory. This approach allows a reliable and precise determination of the adsorption properties of the materials analysed, including, among other things, surface heterogeneities, and thus an appropriate selection of production conditions to obtain materials with the expected adsorption properties required for a given industrial process.

Abstract This paper presents the results of an unique analysis of the influence of the mass ratio of activator FeCl3 to precursor and the temperature of the activation process on the formation of the porous structure of activated carbons obtained from Tara Rubber by FeCl3 activation. The study used the new numerical clustering based adsorption analysis method and the quenched solid density functional theory, taking into account, among other things, the heterogeneity of the analysed surface which is a new approach rarely used in the analysis of the porous structure of adsorbents. On the basis of the calculation results, it was concluded that the activated carbon with the most developed porous texture was obtained at a mass ratio (FeCl3:Tara Rubber) of 2, at an activation process temperature of 800 °C. This activated carbon is also characterised by the lowest degree of surface heterogeneity and at the same time, however, the widest range of micropores compared to activated carbons obtained at other mass ratios. The analyses carried out further demonstrated the valuable and complementary information obtained from the structure analysis methods and their high utility in practical applications, especially in the development of new industrial technologies for the production of adsorbents and the selection of optimal conditions for their production.

Abstract This paper presents the results of a study on the influence of the degree of impregnation and activation temperature on the formation of the porous structure of activated carbons (ACs) obtained from Pine cones by the chemical activation process using potassium hydroxide as an activator. The advanced new numerical clustering based adsorption analysis (LBET) method, together with the implemented unique numerical procedure for the fast multivariant identification were applied to nitrogen and carbon dioxide adsorption isotherms determined for porous structure characterization of the ACs. Moreover, the Quenched Solid Density Functional Theory (QSDFT) method was chosen to determine pore size distributions. The results showed a significant influence of the primary structure of Pine cones on the formation of the porous structure of the developed ACs. Among others, it was evidenced by a very high degree of surface heterogeneity of all the obtained ACs, irrespective of the degree of impregnation with potassium hydroxide and the activation temperature. Moreover, the analysis of carbon dioxide adsorption isotherms showed, that the porous structure of the studied ACs samples contains micropores accessible only to carbon dioxide molecules. The results also showed a significant advantage of the LBET method over those conventionally used for porous structure analysis based on Brunauer–Emmett–Teller (BET) and Dubinin–Raduskevich (DR) equations, because it takes into account surface heterogeneities. The novel analyses methods were more fully validated as a reliable characterization tool, by extending their application to the isotherms for ACs developed from the same precursor by phosphoric acid activation, and for samples arising from these ACs, further subjected to additional post-treatments. The effect of the raw material used as precursor was moreover analysed by comparison with previous reported results for other ACs. The complementarity of the results obtained with the LBET and QSDFT methods is also noteworthy, resulting in a more complete and reliable picture of the analyzed porous structures.

The paper presents the results of an investigation into the effect of the type of activating agent on the formation of the microporous structure of activated carbon monoliths obtained by chemical activation involving calcium chloride, phosphoric(V) acid, and zinc chloride. The research into the microporous structure of the activated carbon monoliths subject to the analysis was based on the innovative method of porous structure analysis along with the unique fast procedure of multivariant identification of adsorptive systems. The analyses carried out with the use of the mentioned method were based on nitrogen, carbon dioxide, and methane adsorption isotherms. The research evidenced that a microporous structure analysis based on various adsorption isotherms and involving the method in question yields comprehensive and reliable information on the adsorptive properties of analysed materials, which is useful for technologists and designers alike. Keywords: Adsorption, Microporous structure, Chemical activation, Active carbons, Methane

The results of the advanced computer analysis of the influence of time and gas atmosphere of the chemical activation process on the microporous structure formation of activated carbons prepared from oil palm shell via microwave irradiation and activation, using potassium hydroxide as an activation agent, are presented in this paper. The quenched solid density functional theory (QSDFT) and the new numerical clustering-based adsorption analysis (LBET) methods were used especially in the analysis of the microporous structure of the activated carbons, taking into account the surface heterogeneity, and the results obtained were confronted with the simple results achieved earlier using Brunauer–Emmett–Teller (BET) and T-plot methods. On the basis of the computer analysis carried out and taking into account the results obtained, it has been shown that the material with the best adsorption properties and suitable for practical industrial applications is activated carbon obtained in a gaseous nitrogen atmosphere at an activation time of 30 min. Moreover, the value of the heterogeneity parameter indicates that the surface area of this activated carbon is homogeneous, which is of particular importance in the practical application. The paper emphasizes that an erroneous approach to the interpretation of analytical results based on gas adsorption isotherms, which consists in basing conclusions only on the values of a single parameter such as specific surface area or micropore volume, should be avoided. Therefore, it is recommended to use in the analysis of measurement data, several methods of porous structure analysis, including methods considering the heterogeneity of the surface, and when interpreting the results one should also take into account the adsorption process for which the analyzed materials are dedicated.