Adsorption最新文献

Metal–organic frameworks (MOFs) are highly porous and crystalline materials synthesized from metal ions and organic ligands. They have received attention from researchers in recent years due to their enormous applications, such as separation, sensors, gas storage, and catalysis. MOFs are categorized as nanoporous, mesoporous, and microporous based on the size of the pores. Functionality of MOFs depends on their pore size and overall charge. BTEX, a subclass of volatile organic compounds found in air, is classified as a hazardous pollutant because of its toxic, carcinogenic, and mutagenic nature. One practical strategy for protecting the environment is the sequestration of multi-component BTEX using MOFs as sorbents. This review discusses the classification of MOFs and highlights the green and economical methodologies adopted for the synthesis of MOFs in order to facilitate their commercialization. This article also presents an overview of the adsorption of BTEX using various types of MOFs. More significantly, plausible processes for the adsorption or interaction of BTEX compounds with MOFs are discussed. The various kinds of interaction, including hydrophobic interactions, π–π stacking, hydrogen bonding, interaction at open metal site, and electrostatic interaction, are discussed. These processes are usually impacted by the ligands' structure and functionalization, the MOFs functionalization, the pore size, and the surface structure of the MOF.

Managing wastewater in industrial laundries poses a significant challenge, particularly in the removal of emerging contaminants such as phenolic compounds. The performance of a two-stage process combining ultrafiltration followed by adsorption using modified activated carbon was studied for the removal of nonylphenol ethoxylate (NPEO_3-17) from real laundry wastewater. The use of ultrafiltration as a pretreatment allowed removing solids and colloids before adsorption. Ultrafiltration led to a reduction in total suspended solids from 14.0 ± 2.1 to 3.0 ± 1.3 mg.L⁻¹ and turbidity from 110 ± 1.4 to 1.8 ± 0.9 NTU. Additionally, NPEO_3-17 concentration decreased from 1095 ± 50 µg.L⁻¹ to 534 ± 78 µg.L⁻¹, whereas the chemical oxygen demand (COD) concentration passed from 585 ± 14 mg.L⁻¹ to 281 ± 9 mg.L⁻¹ in the permeate. The ultrafiltration permeate was subsequently treated by dynamic adsorption. The adsorption process was designed and optimized considering parameters such as hydraulic retention time (HRT), initial feed temperature, and column height-to-diameter (H/D) ratio. HRT was found to be the most important parameter contributing significantly to NPEO_3-17 and COD removal. Under the optimal conditions (HRT of 9.6 min, a temperature of 20 °C, and an H/D ratio of 6.9) using Box-Behnken Design methodology, 99% and 82% of NPEO_3-17 and COD were removed, respectively. The breakthrough behavior of the adsorption column was further analyzed using six classical models including Bohart–Adams, Yoon–Nelson, Thomas, Wolborska, Yan, and Clark, to interpret the dynamic adsorption kinetics and predict column performance. The Bohart-Adams and Wolborska models described very well the adsorption process for NPEO_3-17. Results demonstrated that the modified activated carbon maintained NPEO_3-17 levels below the reuse threshold (< 200 µg.L⁻¹) for water reuse, even after treating nearly 100 L of ultrafiltered water, confirming the efficiency and long-term stability of the hybrid ultrafiltration–adsorption system.

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The pressure swing adsorption (PSA) process has a wide range of applications for CO₂ capture from flue gas, due to the advantages of simple operation, low investment and energy consumption. However, existing research results have shown that conventional single-stage PSA typically cannot achieve 95% purity CO₂ with 90% recovery using most commercial adsorbents. Dual reflux pressure swing adsorption (DR-PSA) is a special process that combines stripping and enriching PSA, where light and heavy products with high purity and high recovery can be obtained simultaneously. However, its industrial applications are limited by the problems of discontinuous feeding and high energy consumption. To overcome these limitations, a 4-bed continuous DR-PSA was developed and simulated using a model validated against published experimental data, with simulated flue gas (CO₂/N₂ = 15%/85%) as the feed and silica gel as the adsorbent. After comparing internal state variables, four key parameters, including feed flow rate, step duration, light reflux-to-feed ratio, and feed position, were studied in detail. The results indicate that the proposed process can achieve CO₂ purity of 96.42% with 96.52% recovery, N₂ purity of 99.40% with 99.40% recovery, a productivity of 0.4607 mol CO₂/kg/h, and a specific energy consumption of 1.172 GJ/t CO₂. The process demonstrates significantly superior specific energy consumption compared to prior studies.

This work reports a comparative analysis of Carbon dioxide (CO₂) adsorption in three different pore-sized Metal organic frameworks (MOFs) named MOF-5, ZIF-8 and UiO-66. The Grand Canonical Monte Carlo (GCMC) simulations have been performed between temperature ranges 258–323 K under 0–30 bar pressure to examine the CO₂ adsorption capacity of the three MOFs.The adsorption isotherms and isosteric heat of adsorption across the three MOFs have been studied to understand their gas storage capacities and adsorption mechanisms. It is observed that MOF-5 outperforms UiO-66 and ZIF-8 in CO₂ adsorption under high pressure at all temperatures. At ambient conditions (298 K and 1 bar), UiO-66 is found to be the best adsorber among the studied MOFs. This study establishes a structure adsorption analysis, linking pore architecture and chemistry with CO₂ uptake behaviour.

A novel copper(II)-based metal-organic framework (MOF), hexakis(4-acetamidobenzoato)dicopper(II), was synthesized via a solution-based reaction using 4-acetamidobenzoic acid and copper(II) chloride. Structural elucidation through single-crystal X-ray diffraction revealed a classical paddle-wheel dicopper(II) core with bidentate bridging by six acetamidobenzoate ligands, forming a distorted square-pyramidal coordination geometry. Spectroscopic analyses (FT-IR, Raman, UV-Vis) confirmed successful metal–ligand coordination, while thermal analysis highlighted multi-step decomposition with stable CuO residue. SEM–EDS and XRF affirmed high crystallinity and homogenous elemental distribution. Hirshfeld surface and DFT-based frontier molecular orbital (FMO) analyses underscored strong intermolecular interactions and semiconducting behavior with a narrow band gap (0.36 eV), indicating potential in catalytic and optoelectronic applications. Adsorption studies demonstrated significant dye uptake capacities, with preferential chemisorption of methyl orange due to favorable structural and electronic properties. Furthermore, the MOF exhibited promising CO₂ and C₂H₂ gas adsorption behavior, with stronger van der Waals interaction and higher uptake for acetylene. These findings demonstrate the multifunctional potential of this copper MOF in environmental remediation, separation technologies, and sensor development.

The hybrid adsorption cooling desalination system presents a dual solution, offering reliable water production and cooling effects, and reducing electricity consumption and greenhouse gas emissions. This study introduces a novel utilization of two promising adsorbent materials (Bentonite/CaCl₂ (Bent/CaCl₂) and Max/CaCl₂) in the adsorption cooling desalination system driven by low-temperature heat, such as solar energy (SE) or waste heat (WH). The proposed system expresses the potential of integrating two types of ejectors, a vapor-vapor ejector and a liquid-vapor ejector, to increase its performance and reduce the cost of freshwater production. This study presents comprehensive mathematical models to investigate the energetic performance and the economic feasibility of the proposed hybrid systems, operating under real meteorological conditions for three distinct locations: Arish (Egypt), Riyadh (Saudi Arabia), and Dubai (United Arab Emirates). Different configurations of the hybrid systems used in cooling and desalination modes (ADCS) were examined, with and without internal evaporator condenser heat recovery and ejectors integration. The numerical results showed that the adsorbent Max/CaCl₂ exhibits the best performance among the tested adsorbents in the cooling and desalination mode. Arish City achieved the highest daily freshwater production and cooling effect with 84.2 m³/ton and 801.3 W/kg in June using Max/CaCl₂, while Dubai exhibited the lowest SCP at 356.5 W/kg in December. Arish exhibited the highest daily freshwater production for evaporator condenser heat recovery mode with ejectors integration, reaching a promising value of 129.9 m³/ton in June. Among the tested adsorbents, the most cost-effective operation was observed in Arish in June, where Max/CaCl₂ achieved the lowest water production cost of $0.385/m³ utilizing a waste heat source. Overall, this study expresses the effectiveness and potential of integrating an adsorption system with ejectors and heat recovery in improving system performance and cost efficiency across different climatic conditions.

Understanding hydrogen adsorption mechanisms on nanostructured materials is essential for advancing safe and efficient hydrogen-based energy technologies. In this study, we performed a Density Functional Theory (DFT) investigation to evaluate the interaction of H₂ molecules with B₁₂N₁₂ nanocages decorated with Y, Zr, and Nb. The most stable configurations, Y@b64, Zr@r4e, and Nb@b66—adsorbed up to 5, 4, and 3 H₂ molecules, respectively. The first H₂ molecule was dissociatively adsorbed with strong interaction energies (− 1.71 to − 1.85 eV), while the remaining were molecularly adsorbed with average energies between − 0.29 and − 0.38 eV/H₂. Desorption temperature calculations (T_D = 370–490 K) indicated favorable retention at ambient conditions and potential for controlled release. Molecular dynamics (MD) simulations (500 ps) revealed partial desorption, with 3, 2, and 1 H₂ molecules retained in Y@b64, Zr@r4e, and Nb@b66, respectively. The corresponding gravimetric hydrogen content values were below the DOE. Nevertheless, the systems exhibit adsorption behavior comparable to Ti- and Nb-decorated fullerenes and graphene-based materials. These results highlight the potential of B₁₂N₁₂ nanocages as model platforms for selective H₂ interaction and pave the way for future structural optimizations aiming at practical solid-state hydrogen storage.

Post synthetic modification of metal organic frameworks presents a viable route for amine functionalization which can significantly enhance CO₂ sorption capacity. We present a facile means of amine incorporation using limited synthetic steps and low-cost reagents that results in a high density of primary alkyl amines distributed through a zirconium-based metal organic framework (MOF). Both the MOF synthesis and the post synthetic modification take place under aqueous conditions and result in strongly bound molecular amines available for sorbate interaction throughout the MOF pores. This amine incorporation protocol results in a significantly increased CO₂ capacity compared with the unmodified MOF-808. Specifically, CO₂ isotherms collected at 298 K for the unmodified MOF-808 show uptakes of 0.06, 0.2, and 1.2 mmol/g at 4, 15, and 100 kPa, respectively, which can be compared with 0.3, 0.7, and 2.5 mmol/g for the glycine grafted MOF-808 and 0.5, 0.9, and 2.3 mmol/g for ethylenediamine grafted MOF-808.

It has been recently revealed that hydrogen storage on the surfaces of mesoporous materials such as MCM-41, especially within their internal cavities, is enhanced in the presence of transition metals such as nickel and palladium. Therefore, in this study, hydrogen storage was examined theoretically into the MCM-41 mesoporous silica model. Plane-wave DFT calculations revealed the adsorption of hydrogen molecules into the MCM-41 model when nickel and palladium metals were present. Additionally, in the Metropolis Monte Carlo simulations, it was observed that the hydrogen molecule adsorption capacity increased with the amount of metal. For example, the amount of adsorbed hydrogen molecules at a pressure of 10 bar and 298 K temperature in systems containing 2.3% by weight of nickel and palladium was found to be 0.28% and 0.15%, respectively. When the metal content was approximately doubled, these values increased to 0.53% and 0.34% under the same pressure and temperature. When the temperature is decreased to 77 K, the amount of adsorbed H₂ increases to 1.2 wt% H₂ for the model with 23% Ni and 1.0 wt% H₂ for the model with the same percentage of Pd at 10 bar pressure. On the other hand, due to the H-bonds, hydrogen molecules interacted with the oxygen atoms belonging to pure MCM-41. Based on these results, it is evident from all theoretical studies that loading an equivalent weight ratio of Ni exhibited a higher hydrogen storage capacity compared to Pd. Moreover, it can be said that the MCM-41 model constructed in this theoretical study aligns well with literature as an ideal material for hydrogen storage.