A novel fructose-based adsorbent with high capacity and its ethane-selective adsorption property

High-Purity Ethylene Production from Ethane/Ethylene Mixtures at Ambient Conditions by Ethane-Selective Fluorine-Doped Activated Carbon Adsorbents

Energy-efficient separation of light alkanes from alkenes is considered as one of the most important separations of the chemical industry today due to the high energy penalty associated with the applied conventional cryogenic technologies. This study introduces fluorine-doped activated carbon adsorbents, where elemental fluorine incorporation into the carbon matrix plays a unique role in achieving high ethane selectivity. This enhanced selectivity arises from specific interactions between surface-doped fluorine atoms and ethane molecules, coupled with porosity modulation. Consequently, an equilibrium ethane/ethylene selectivity of as high as 3.9 at 298 K and 1 bar was achieved. Furthermore, polymer-grade ethylene (purity >99.99%) with a productivity of 1.6 mmol/g was obtained in a breakthrough run at ambient conditions from a binary ethane/ethylene (1/9 v/v) mixture. The ethane selectivity of the fluorine-doped carbons was further elucidated through Monte Carlo simulations and density contours of the adsorbed components. In addition to the high ethane selectivity, the adsorbents exhibited a hydrophobic surface, high stability under moisture, and excellent regenerability over multiple adsorption-desorption cycles under both equilibrium and dynamic conditions, demonstrating a sustainable performance.

Impact of molecular structure on the biological removal efficiency of fluoroquinolone antibiotics: An in-silico approach

Fluoroquinolone antibiotics (FQs), one of the most widely used antibacterials, have been recognized as emerging contaminants with adverse human health concerns. To overcome the adverse effects, a theoretical molecular design and screening approach was developed in this study to improve the removal efficiency of FQs by Chlorella in artificial or natural wetland systems. Among the 189 designed norfloxacin (NOR) derivatives, NOR-140 was screened with significantly improved biosorption, bioaccumulation, and biodegradation removal and functional effects, and reduced human health and ecological risks. The removal mechanism NOR-140 was also analyzed using adsorption kinetics, molecular docking, molecular dynamics simulations and machine learning models. Protein and polysaccharide structures play a major role in the adsorption process, polarizability and molecular volume of NOR-140 affect the bioaccumulation ability, and hydrogen bonding was found as the key force promoting the degradation ability of NOR-140. Modifying specific sites (5, 8, and 13) with functional groups containing highly electronegative atoms (O, F) significantly enhances the biodegradability of FQs alternatives by Chlorella. This study provided theoretical support for designing environmentally friendly FQs alternatives with improved degradation ability and advanced the understanding of how the FQs' molecular structures affect its removal by Chlorella.

Elucidating the mechanisms of Paraffin-Olefin separations using nanoporous adsorbents: An overview

Light olefins are the precursors of all modern-day plastics. Olefin is always mixed with paraffins in the time of production, and therefore it needs to be separated from paraffins to produce polymer-grade olefin. The state-of-the-art separation technique, cryogenic distillation, is highly expensive and hazardous. Adsorption could be a novel, sustainable, and inexpensive separation strategy, provided a suitable adsorbent can be designed. There are different types of mechanisms that were harnessed for the separation of olefins by adsorption, and in this review, we have focused our discussion on those mechanisms. These mechanisms include, (a) Affinity-based separation, like pi complexation and hydrogen bonding, (b) Separation based on pore size and shape, like size-exclusion and gate-opening effect, and (c) Non-equilibrium separation, like kinetic separation. In this review, we have elaborated each of the separation strategies from the fundamental level and explained their roles in the separation processes of different types of paraffins and olefins.

Microporous 3D Graphene-like Zeolite-Templated Carbons for Preferential Adsorption of Ethane

Microporous 3D graphene-like carbons were synthesized in Faujasite (FAU)-, EMT-, and beta-zeolite templates using the recently developed Ca²⁺ ion-catalyzed synthesis method. The microporous carbons liberated from these large-pore zeolites (0.7-0.9 nm) retain the structural regularity of zeolite. FAU-, EMT-, and beta zeolite-templated carbons (ZTCs) with faithfully constructed pore diameters of 1.2, 1.1, and 0.9 nm, respectively, and very large Brunauer-Emmet-Teller areas (2700-3200 m² g^-1) were obtained. We have discovered that these schwarzite-like carbons exhibit preferential adsorption of ethane over ethylene at pressures in the range of 1-10 bar. The curved graphene structure, consisting of a diverse range of carbon polygons with a narrow pore size of ∼1 nm, provides abundant adsorption sites in micropores and retains its ethane selectivity at pressures up to 10 bar. After varying the oxygen content in the beta ZTC, the ethane and ethylene adsorption isotherms show that the separation ability is not significantly affected by surface oxygen groups. Based on these adsorption results, a breakthrough separation procedure using a C₂H₄/C₂H₆ gas mixture (9:1 molar ratio) is demonstrated to produce ethylene with a purity of 99.9%.