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Predicting adsorption on nanoporous carbonaceous materials is important for developing various adsorption and membrane separations, as well as for oil and gas recovery from shale reservoirs. Here, we explore the capabilities of 3D molecular models of disordered carbon structures to reproduce the morphological and adsorption features of practical adsorbents. Using grand canonical Monte Carlo simulations, we construct a series of adsorption isotherms of simple fluids (N 2 , Ar, CO 2 , and SO 2) and a series of alkanes from methane to hexane on two model 3D structures, purely microporous structure A and micro-mesoporous structure B. We show that structure A reproduces the morphological properties of commercial Norit R1 Extra activated carbon and demonstrates outstanding agreement between the simulated and experimental adsorption isotherms reported in the literature for all adsorbates considered. Good agreement is also found for simulated and measured isosteric heats. Taking into account inherent variability of structural properties of commercial carbons and experimental adsorption data from different literature sources, the correlations with experiments are truly amazing. This work provides a new insight into the specifics of structural and adsorption properties of nanoporous carbons and demonstrates the advantages of using 3D molecular models for predicting adsorption hydrocarbons and other chemicals by MC simulations. [Display omitted] • 3D molecular models replicate morphological specifics of nanoporous carbons characterized by geometric and adsorption methods. • Monte Carlo generated isotherms of adsorption of simple fluids and hydrocarbons are in good agreement with experimental data on Norit R1 Extra. • Monte Carlo simulations on 3D models reveal the mechanisms of gas adsorption on micro-mesoporous carbons not seen with standard adsorption models. [ABSTRACT FROM AUTHOR]

Background: The excess sludge produced by sewage treatment plants contains a large number of pollutants, which is of huge environmental risk. Transforming this kind of solid waste into adsorption materials is an effective approach to realize the resource utilization of sludge. Combined with hydrothermal pretreatment and chemical activation, the synthesis of sludge‐based mesoporous carbon is used to remove bisphenol A (BPA) in wastewater. Results: A resource recycling measure to prepare mesoporous activated carbons (MACs) from sewage sludge was developed via the combination of hydrothermal pretreatment and chemical activation using sewage sludge and sulfuric acid as carbon precursor and activating agent, respectively. The combination of hydrothermal pretreatment and chemical activation not only can make efficient use of the activating agents but also facilitate the deep pyrolysis of the sludge. The resultant MAC obtained using the hydrothermal pretreatment possessed a larger total surface area, less crystalline phase and a narrower pore size distribution compared to other samples. Meanwhile, the MAC obtained from hydrothermal pretreatment presented the highest amount of adsorption of BPA and achieved a better capture than the reference commercial activated carbons. In addition, a possible adsorption mechanism has been proposed to further analyze the enhanced adsorption performance. Conclusions: The yield and mesoporous content of the obtained MAC is 59.19% and 31.51%, respectively. The maximum adsorption capacity for BPA is 137.87 mg g−1. Microporosity, hydrogen bonding and π–π effect introduced by the hydrothermal pretreatment play an important role in BPA adsorption. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A modified non-local free energy density functional theory (NDFT) model, with the consideration of the nonadditivity term of solid-fluid and fluid-fluid interactions and finite pore wall thickness (≈2 layers), was developed to model the confined fluid mixtures in slit pore. This improved NDFT approach, combining with the pore size distribution (PSD) analysis of adsorbent material can be applied to predicting the adsorption equilibria of high-pressure gas mixtures on activated carbon. Compared with the conventional NDFT method, this new approach partly improves the correlation performance of adsorption equilibrium for pure species and increases the reliability of the PSD analysis. For the mixtures, CH4/N2 and CO2/N2, a relatively improved performance has been observed for the adsorption equilibrium prediction of the mixtures under high-pressure conditions, especially for the weakly adsorbed species. [ABSTRACT FROM AUTHOR]

Abstract: The fields of applicability of headspace sorptive extraction (HSSE) and stir bar sorptive extraction (SBSE) using polydimethylsiloxane (PDMS) as sorbent have been intensively discussed and widely described. One of the limits of sorptive extraction is that PDMS (i.e. an apolar phase) is the only polymer currently in use making it difficult to recover polar analytes from complex or multi-ingredient matrices and those with very volatile components (C1–C4 analytes). Dual-phase twisters are here introduced as new tools for HSSE and SBSE to overcome the above limits. Dual-phase twisters combine the concentration capabilities of two or more sampling materials operating in different ways (in this case sorption and adsorption). The new twisters consist of a short PDMS tube the ends of which are closed with two magnetic stoppers, thus creating an inner cavity that can be packed with different types of adsorbents like activated carbons. The concentration capability of dual-phase twisters was evaluated by using them for the HSSE and SBSE sampling of a number of matrices in the vegetable, food and environmental fields. The contributions made by different carbons to recovery, repeatability and intermediate precision were also investigated. [Copyright &y& Elsevier]