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1.
ChemistryOpen ; : e202400110, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38738745

RESUMO

Catalytic transformation of CO2 into value-added chemical products can provide an appropriate solution for the raising environmental issues. To date, various metal-organic frameworks (MOFs) with transition metal ions have been explored for CO2 capture and conversion, but alkaline earth metal-based MOFs are comparatively less studied. Metal ions like Sr(II) having relatively large radius give rise to a high coordination number resulting in higher stability of the MOFs. Moreover, the introduction of N-rich functional group in organic linker like -NH2, -CONH- and triazole into MOF backbone enhance their CO2 capture and conversion efficiency. Herein, the effect of amine group on the catalytic efficiency of MOFs for CO2 cycloaddition with epoxides under solvent free and ambient conditions are presented. The di-carboxylates, such as 5-aminoisophthalate (AmIP) and 5-bromoisophthalate (BrIP) were utilized to synthesize Sr(II) based MOFs. The Zn(II) MOF was synthesized using tetra-carboxylate containing amide spacer (OAT) and 4-amino-4H-1,2,4-triazole (AMT). All three MOFs exhibited porous networks with guest available volume ranging from 15 to 58 %. The catalytic efficiency of the MOFs towards carbon dioxide fixation reaction was explored. The catalytic performances revealed that the presence of amine group in the channels enhances the catalytic efficiency of the MOFs.

2.
Chemosphere ; 358: 142198, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38697566

RESUMO

In the electrical industry, there are many hazardous gases that pollute the environment and even jeopardize human health, so timely detection and effective control of these hazardous gases is of great significance. In this work, the gas-sensitive properties of Pd-modified g-C3N4 interface for each hazardous gas molecule were investigated from a microscopic viewpoint, taking the hazardous gases (CO, NOx) that may be generated in the power industry as the detection target. Then, the performance of Pd-modifiedg-C3N4 was evaluated for practical applications as a gas sensor material. Novelly, an unconventional means was designed to briefly predict the effect of humidity on the adsorption properties of this sensor material. The final results found that Pd-modified g-C3N4 is most suitable as a potential gas-sensitizing material for NO2 gas sensors, followed by CO. Interestingly, Pd-modified g-C3N4 is less suitable as a potential gas-sensitizing material for NO gas sensors, but has the potential to be used as a NO cleaner (adsorbent). Unconventional simulation explorations of humidity effects show that in practical applications Pd-modified g-C3N4 remains a promising material for gas sensing in specific humidity environments. This work reveals the origin of the excellent properties of Pd-modified g-C3N4 as a gas sensor material and provides new ideas for the detection and treatment of these three hazardous gases.


Assuntos
Poluentes Atmosféricos , Paládio , Poluentes Atmosféricos/análise , Paládio/química , Adsorção , Água/química , Monitoramento Ambiental/métodos , Gases/análise , Umidade , Monóxido de Carbono/análise , Nitrilas/química , Nitrilas/análise
3.
J Hazard Mater ; 472: 134311, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38691989

RESUMO

This study proposes a predictive model for assessing adsorber performance in gas purification processes, specifically targeting the removal of chemical warfare agents (CWAs) using breakthrough curve analysis. Conventional parameter estimation methods, such as Brunauer-Emmett-Teller analysis, encounter challenges due to the limited availability of kinetic and equilibrium data for CWAs. To overcome these challenges, we implement a Bayesian parametric inference method, facilitating direct parameter estimation from breakthrough curves. The model's efficacy is confirmed by applying it to H2S purification in a fixed-bed setup, where predicted breakthrough curves aligned closely with previous experimental and numerical studies. Furthermore, the model is applied to sarin with ASZM-TEDA carbon, estimating key parameters that could not be assessed through conventional experimental techniques. The reconstructed breakthrough curves closely match actual measurements, highlighting the model's accuracy and robustness. This study not only enhances filter performance prediction for CWAs but also offers a streamlined approach for evaluating gas purification technologies under limited experimental data conditions.

4.
ACS Appl Mater Interfaces ; 16(20): 26395-26405, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38728440

RESUMO

Detection of leaks of flammable methane (CH4) gas in a timely manner can mitigate health, safety, and environmental risks. Zinc oxide (ZnO), a polar semiconductor with controllable surface defects, is a promising material for gas sensing. In this study, Ag-Ru co-doped into self-assembled ZnO nanorod arrays (ZnO NRs) was prepared by a one-step hydrothermal method. The Ag-Ru co-doped sample shows a good hydrophobic property as a result of its particular microstructure, which results in high humidity resistance. In addition, oxygen vacancy density significantly increased after Ag-Ru co-doping. Density functional theory (DFT) calculations revealed an exceptionally high charge density accumulated at the Ru sites and the formation of a localized strong electric field, which provides additional energy for the CH4 reaction with •O2- at the surface at room temperature. Optimized AgRu0.025-ZnO demonstrated an outstanding CH4 sensing performance, with a limit of detection (LOD) as low as 2.24 ppm under free-heat and free-light conditions. These findings suggest that introducing defects into the ZnO lattice, such as oxygen vacancies and localized ions, offers a promising approach to improving the gas sensing performance.

5.
Environ Sci Technol ; 58(19): 8313-8325, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38689207

RESUMO

CO2 is 45 to 50 times more concentrated in soil than in air, resulting in global diffusive fluxes that outpace fossil fuel combustion by an order of magnitude. Despite the scale of soil CO2 emissions, soil-based climate change mitigation strategies are underdeveloped. Existing approaches, such as enhanced weathering and sustainable land management, show promise but continue to face deployment barriers. We introduce an alternative approach: the use of solid adsorbents to directly capture CO2 in soils. Biomass-derived adsorbents could exploit favorable soil CO2 adsorption thermodynamics while also sequestering solid carbon. Despite this potential, previous study of porous carbon CO2 adsorption is mostly limited to single-component measurements and conditions irrelevant to soil. Here, we probe sorption under simplified soil conditions (0.2 to 3% CO2 in balance air at ambient temperature and pressure) and provide physical and chemical characterization data to correlate material properties to sorption performance. We show that minimally engineered pyrogenic carbons exhibit CO2 sorption capacities comparable to or greater than those of advanced sorbent materials. Compared to textural features, sorbent carbon bond morphology substantially influences low-pressure CO2 adsorption. Our findings enhance understanding of gas adsorption on porous carbons and inform the development of effective soil-based climate change mitigation approaches.


Assuntos
Dióxido de Carbono , Carbono , Solo , Dióxido de Carbono/química , Solo/química , Porosidade , Adsorção , Carbono/química , Carvão Vegetal/química , Mudança Climática
6.
Angew Chem Int Ed Engl ; 63(28): e202405027, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38656532

RESUMO

A novel class of crystalline porous materials has been developed utilizing multilevel dynamic linkages, including covalent B-O, dative B←N and hydrogen bonds. Typically, boronic acids undergo in situ condensation to afford B3O3-based units, which further extend to molecular complexes or chains via B←N bonds. The obtained superstructures are subsequently interconnected via hydrogen bonds and π-π interactions, producing crystalline porous organic frameworks (CPOFs). The CPOFs display excellent solution processability, allowing dissolution and subsequent crystallization to their original structures, independent of recrystallization conditions, possibly due to the diverse bond energies of the involved interactions. Significantly, the CPOFs can be synthesized on a gram-scale using cost-effective monomers. In addition, the numerous acidic sites endow the CPOFs with high NH3 capacity, surpassing most porous organic materials and commercial materials.

7.
ChemSusChem ; : e202301145, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38578225

RESUMO

Graphitic nanoplatelets (GnPs), edge-selectively carboxylated graphitic nanoplatelets (ECGnPs), are functionalized with a carboxylic acid at the edge increasing their surface area, and are highly dispersible in various solvents. However, there is a limit in that the basal plane remains intact because it is functionalized only in the part where the radical is generated at the edge. Here, we activate ECGnPs to have porous structures by flowing CO2 at 900 °C. Etching of the ECGnPs structure was performed through the Boudouard reaction, and the surface area increased from 579 m2 g-1 to a maximum of 2462 m2 g-1. In addition, the pore structure was investigated with various adsorption gases (CH4, Ar, CO2, H2, and N2) according to the reaction time. This study provides the overall green chemistry in that it utilizes CO2 from manufacturing to activation compared to the process of activating with conventional chemical treatment.

8.
Chemistry ; 30(34): e202400947, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38622630

RESUMO

Two crystalline large-sized porous organic cages (POCs) based on conical calix[4]arene (C4A) were designed and synthesized. The four-jaw C4A unit tends to follow the face-directed self-assembly law with the planar triangular building blocks such as tris(4-aminophenyl)amine (TAPA) or 1,3,5-tris(4-aminophenyl)benzene (TAPB) to generate a predictable cage with a stoichiometry of [6+8]. The formation of the large cages is confirmed through their relative molecular mass measured using MALDI-TOF/TOF spectra. The protonated molecular ion peaks of C4A-TAPA and C4A-TAPB were observed at m/z 5109.0 (calculated for C336H240O24N32: m/z 5109.7) and m/z 5594.2 (calculated for C384H264O24N24: m/z 5598.4). C4A-POCs exhibit I-type N2 adsorption-desorption isotherms with the BET surface areas of 1444.9 m2 ⋅ g-1 and 1014.6 m2 ⋅ g-1. The CO2 uptakes at 273 K are 62.1 cm3 ⋅ g-1 and 52.4 cm3 ⋅ g-1 at a pressure of 100 KPa. The saturated iodine vapor static uptakes at 348 K are 3.9 g ⋅ g-1 and 3.5 g ⋅ g-1. The adsorption capacity of C4A-TAPA for SO2 reaches to 124.4 cm3 ⋅ g-1 at 298 K and 1.3 bar. Additionally, the adsorption capacities of C4A-TAPA for C2H2, C2H4, and C2H6 were evaluated.

9.
Materials (Basel) ; 17(5)2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38473496

RESUMO

To address the most significant environmental challenges, the quest for high-performance gas sensing materials is crucial. Among numerous two-dimensional materials, this study investigates the gas-sensitive capabilities of monolayer As, Sb, and Bi materials. To compare the gas detection abilities of these three materials, we employ first-principles calculations to comprehensively study the adsorption behavior of NO and NO2 gas molecules on the material surfaces. The results indicate that monolayer Bi material exhibits reasonable adsorption distances, substantial adsorption energies, and significant charge transfer for both NO and NO2 gases. Therefore, among the materials studied, it demonstrates the best gas detection capability. Furthermore, monolayer As and Sb materials exhibit remarkably high capacities for adsorbing NO and NO2 gas molecules, firmly interacting with the gas molecules. Gas adsorption induces changes in the material's work function, suggesting the potential application of these two materials as catalysts.

10.
J Mol Model ; 30(3): 72, 2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38366130

RESUMO

CONTEXT: Graphene-based nanomaterial was widely used in gas sensors, detection, and separation. However, weak adsorption and low selectivity of the pristine graphene used for gas sensors are major problems. Here, using density functional theory (DFT) calculations, we reported the significant increase of four gas molecules (N2, CO2, C2H2, and C2H4) adsorption on the transition metal ion (Fe3+, Co2+, Ni2+)-modified graphene complex (Fe3+/Co2+/Ni2+-G) comparing to be absorbed on the pristine graphene (G). Moreover, the Co2+-G is suitable for the selective separation of C2H4/C2H2 due to the larger adsorption energy difference (8.5 kcal/mol) between them. The addition of transition metal ions also decreased the HOMO-LUMO gap of the systems, which benefits the enhancement of electrical conductivity. This suggests that the transition metal ion-modified graphene can be used to distinguish the different gas molecule's adsorption, facilitating the design of graphene-based gas sensors and selective separation. METHODS: All the density functional theory (DFT) calculations were performed by B3LYP with the GD3 dispersion method using Gaussian 16 software. The basis set 6-31G(d) was used for C, H, O, and N atoms, and Lanl2DZ was used for transition metal ions (Fe3+, Co2+, Ni2+). The DOS analysis and energy decomposition analysis were performed using the Multiwfn program.

11.
ACS Appl Mater Interfaces ; 16(9): 11605-11616, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38407024

RESUMO

Covalent organic frameworks (COFs) having a large surface area, porosity, and substantial amounts of heteroatom content are recognized as the ideal class of materials for energy storage and gas sorption applications. In this work, we have synthesized four different porous COF materials by the polycondensation of a heteroatom-rich flexible triazine-based trialdehyde linker, namely 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine (TPT-CHO), with four different triamine linkers. Triamine linkers were chosen based on differences in size, symmetry, planarity, and heteroatom content, leading to the synthesis of four different COF materials named IITR-COF-1, IITR-COF-2, IITR-COF-3, and IITR-COF-4. IITR-COF-1, synthesized within 24 h from the most planar and largest amine monomer, exhibited the largest Brunauer-Emmett-Teller (BET) surface area of 2830 m2 g-1, superior crystallinity, and remarkable reproducibility compared to the other COFs. All of the synthesized COFs were explored for energy and gas storage applications. It is shown that the surface area and redox-active triazene rings in the materials have a profound effect on energy and gas storage enhancement. In a three-electrode setup, IITR-COF-1 achieved an electrochemical stability potential window (ESPW) of 2.0 V, demonstrating a high specific capacitance of 182.6 F g-1 with energy and power densities of 101.5 Wh kg-1 and 298.3 W kg-1, respectively, at a current density of 0.3 A g-1 in 0.5 M K2SO4 (aq) with long-term durability. The symmetric supercapacitor of IITR-COF-1//IITR-COF-1 exhibited a notable specific capacitance of 30.5 F g-1 and an energy density of 17.0 Wh kg-1 at a current density of 0.12 A g-1. At the same time, it demonstrated 111.3% retention of its initial specific capacitance after 10k charge-discharge cycles. Moreover, it exhibited exceptional CO2 capture capacity of 25.90 and 10.10 wt % at 273 and 298 K, respectively, with 2.1 wt % of H2 storage capacity at 77 K and 1 bar.

12.
ACS Appl Mater Interfaces ; 16(8): 10468-10474, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38359417

RESUMO

The development of efficient technology for natural gas separation in industrial processes has become imperative. In this regard, the exploration of novel and effective adsorbents has gained significant attention. One promising approach is the metal regulation of metal-organic frameworks (MOFs), particularly heterometallic MOFs, which offer greater potential for gas separation due to their diverse composition. This study presents the synthesis of a series of iron- and vanadium-based heterometallic MOFs (MIL-126), featuring interpenetrated structures, and investigates their adsorption performance for methane (CH4), ethane (C2H6), and propane (C3H8). Experimental results reveal that the choice of metal combinations within the MOF framework significantly influences the adsorption performance of MIL-126. Notably, heterometallic MIL-126(Fe/Ni) exhibits a stronger binding affinity for C3H8, with an impressive uptake of 177 cm3/g. The C3H8/CH4 ideal adsorbed solution theory selectivity of MIL-126(Fe/Ni) surpasses that of MIL-126(Fe) by a factor of 7, reaching a value of 853, second only to the highest reported value. Furthermore, MIL-126(Fe/Ni) exhibits remarkable potential for the recovery of pure CH4 from the equimolar C3H8/CH4 mixture, with the amount of pure CH4 approaching the maximum reported value for MOFs. Insights from isosteric heat at zero loading and Henry's coefficients indicate that the transformation of metal types leads to a change in the interaction energy between C3H8 and the framework. Furthermore, breakthrough experiments validate the effective separation capability of MIL-126(Fe/Ni) for CH4/C2H6/C3H8 mixtures. These findings underscore the remarkable potential of heterometallic MOFs in constructing a wide range of new MOFs with tailorable properties, thereby enhancing their gas separation performance.

13.
Angew Chem Int Ed Engl ; 63(15): e202319978, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38369652

RESUMO

Ethylene (C2H4) purification and propylene (C3H6) recovery are highly relevant in polymer synthesis, yet developing physisorbents for these industrial separation faces the challenges of merging easy scalability, economic feasibility, high moisture stability with great separation efficiency. Herein, we reported a robust and scalable MOF (MAC-4) for simultaneous recovery of C3H6 and C2H4. Through creating nonpolar pores decorated by accessible N/O sites, MAC-4 displays top-tier uptakes and selectivities for C2H6 and C3H6 over C2H4 at ambient conditions. Molecular modelling combined with infrared spectroscopy revealed that C2H6 and C3H6 molecules were trapped in the framework with stronger contacts relative to C2H4. Breakthrough experiments demonstrated exceptional separation performance for binary C2H6/C2H4 and C3H6/C2H4 as well as ternary C3H6/C2H6/C2H4 mixtures, simultaneously affording record productivities of 27.4 and 36.2 L kg-1 for high-purity C2H4 (≥99.9 %) and C3H6 (≥99.5 %). MAC-4 was facilely prepared at deckgram-scale under reflux condition within 3 hours, making it as a smart MOF to address challenging gas separations.

14.
ACS Appl Mater Interfaces ; 16(5): 6579-6588, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38275141

RESUMO

Purifying C2H6/C3H8 from a ternary natural gas mixture through adsorption separation is an important but challenging process in the petrochemical industry. To address this challenge, the industry is exploring effective strategies for designing high-performance adsorbents. In this study, we present two metal-organic frameworks (MOFs), DMOF-TF and DMOF-(CF3)2, which have fluorinated pores obtained by substituting linker ligands in the host material. This pore engineering strategy not only provides suitable pore confinement but also enhances the adsorption capacities for C2H6/C3H8 by providing additional binding sites. Theoretical calculations and transient breakthrough experiments show that the introduction of F atoms not only improves the efficiency of natural gas separation but also provides multiple adsorption sites for C2H6/C3H8-framework interactions.

15.
Adv Sci (Weinh) ; 11(13): e2308123, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38240582

RESUMO

Fluoro- and chlorofluorocabons (FC/CFCs) are important refrigerants, solvents, and fluoropolymers in industry while being toxic and carrying high global warming potential. Detection and reclamation of FC/CFCs based on adsorption technology with highly selective adsorbents is important to labor safety and environmental protection. Herein, the study reports an integrated method to combine capture, separation, enrichment, and analysis of representative FC/CFCs (chlorodifluoromethane(R22) and 1,1,1,2-tetrafluoroethane (R134a)) by using the highly stable and porous Zr-MOF, DUT-67. Gas adsorption and breakthrough experiments demonstrate that DUT-67 has high R22/R134a uptake (124/116 cm3 g-1) and excellent R22/R134a/CO2 separation performance (IAST selectivities of R22/CO2 and R134a/CO2 ranging from 51.4 to 33.3, and 31.1 to 25.8), even in rather low concentration and humid conditions. A semi-quantitative analysis protocol is set up to analyze the low concentrations of R22/R134a based on the high selective R22/R134a adsorption ability, fast adsorption kinetics, water-resistant utility, facile regeneration, and excellent recyclability of DUT-67. In situ single-crystal X-ray diffraction, theoretical calculations, and in situ diffuse reflectance infrared Fourier transform spectra have been employed to understand the adsorption mechanism. This work may provide a potential adsorbent for purge and trap technique under room temperature, thus promoting the application of MOFs for VOCs sampling and quantitative analysis.

16.
Adv Sci (Weinh) ; 11(2): e2307417, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37985922

RESUMO

A coordination network containing isolated pores without interconnecting channels is prepared from a tetrahedral ligand and copper(I) iodide. Despite the lack of accessibility, CO2 is selectively adsorbed into these pores at 298 K and then retained for more than one week while exposed to the atmosphere. The CO2 adsorption energy and diffusion mechanism throughout the network are simulated using Matlantis, which helps to rationalize the experimental results. CO2 enters the isolated voids through transient channels, termed "magic doors", which can momentarily appear within the structure. Once inside the voids, CO2 remains locked in limiting its escape. This mechanism is facilitated by the flexibility of organic ligands and the pivot motion of cluster units. In situ powder X-ray diffraction revealed that the crystal structure change is negligible before and after CO2 capture, unlike gate-opening coordination networks. The uncovered CO2 sorption and retention ability paves the way for the design of sorbents based on isolated voids.

17.
Chempluschem ; 89(1): e202300455, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37864516

RESUMO

In this report, a microporous metal-organic framework of [Ca(TDC)(DMA)]n (1) and a two-dimensional coordination polymer of [Ca(TDC)(DMF)2 ]n (2), (TDC2- =Thiophene-2,5-dicarboxylate, DMA=N, N'-dimethylacetamide and DMF=N, N'-dimethylformamide) based on Ca(II) were designed by the effect of solvent, and X-ray analysis was performed for the single crystals of 1 and 2. Then, compound 1 was synthesized in three different methods and identified with a set of analyses. Compared to other adsorbents, MOFs are widely used in the field of adsorption and separation of various gases due to a series of distinctive features such as diverse and adjustable structures pores with different dimensions, high porosity and surface area with regular distribution of active sites. Therefore, the ability of 1 to uptake single gases (CH4 , CO2 , C2 H2 , H2, and N2 ) and separation of several binary mixtures of gases (CO2 /CH4 , CO2 /N2 , CO2 /H2 and CO2 /C2 H2 ), were investigated using Grand Canonical Monte Carlo simulations. Volumetric and gravimetric adsorption isotherms in various operating conditions, the isosteric heat of adsorption (qst ), the chemical potential for each thermodynamic state, and snapshots during the simulation process were reported in all cases. The results obtained from the adsorption simulation indicate that compound 1 has a high capacity for uptake of H2 (16 mmol g-1 ) and N2 (12.5 mmol g-1 ), CO2 (6.6 mmol g-1 ), C2 H2 (5 mmol g-1 ) and CH4 (1.5 mmol g-1 ) gases at 1 bar. It also performs well in separating CO2 in binary mixtures, which can be attributed to the presence of open metal sites in nodes of 1 and their electrostatic tendency to interact with CO2 containing the higher quadrupole dipole moment compared to other components of the mixture.

18.
Front Chem ; 11: 1333475, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38156020

RESUMO

Capturing and separating carbon dioxide, particularly using porous carbon adsorption separation technology, has received considerable research attention due to its advantages such as low cost and ease of regeneration. In this study, we successfully developed a one-step carbonization activation method using freeze-thaw pre-mix treatment to prepare high-nitrogen-content microporous nitrogen-doped carbon materials. These materials hold promise for capturing and separating CO2 from complex gas mixtures, such as biogas. The nitrogen content of the prepared carbon adsorbents reaches as high as 13.08 wt%, and they exhibit excellent CO2 adsorption performance under standard conditions (1 bar, 273 K/298 K), achieving 6.97 mmol/g and 3.77 mmol/g, respectively. Furthermore, according to Ideal Adsorption Solution Theory (IAST) analysis, these materials demonstrate material selectivity for CO2/CH4 (10 v:90 v) and CO2/CH4 (50 v:50 v) of 33.3 and 21.8, respectively, at 1 bar and 298 K. This study provides a promising CO2 adsorption and separation adsorbent that can be used in the efficient purification process for carbon dioxide, potentially reducing greenhouse gas emissions in industrial and energy production, thus offering robust support for addressing climate change and achieving more environmentally friendly energy production and carbon capture goals.

19.
ACS Appl Mater Interfaces ; 15(46): 53395-53404, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37934853

RESUMO

This study investigates the use of chitosan hydrogel microspheres as a template for growing an extended network of MOF-type HKUST-1. Different drying methods (supercritical CO2, freeze-drying, and vacuum drying) were used to generate three-dimensional polysaccharide nanofibrils embedding MOF nanoclusters. The resulting HKUST-1@Chitosan beads exhibit uniform and stable loadings of HKUST-1 and were used for the adsorption of CO2, CH4, Xe, and Kr. The maximum adsorption capacity of CO2 was found to be 1.98 mmol·g-1 at 298 K and 1 bar, which is significantly higher than those of most MOF-based composite materials. Based on Henry's constants, thus-prepared HKUST-1@CS beads also exhibit fair selectivity for CO2 over CH4 and Xe over Kr, making them promising candidates for capture and separation applications.

20.
Environ Sci Pollut Res Int ; 30(52): 112892-112907, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37840082

RESUMO

Coal spontaneous combustion in the gob poses a significant threat to coal mining operations. Designing optimal process parameters for nitrogen injection to prevent and control fires efficiently is crucial. To achieve this, a multi-field coupling equation was established, considering the adsorption of coal to gas. The model's accuracy was verified on-site, and the effects of nitrogen injection at different locations and flow rates were simulated. The optimal injection parameters were determined by analyzing temperature and inerting time. The results showed that the coal spontaneous combustion hazardous zone in the gob tested on-site was consistent with the simulation from the perspective of physisorption. Nitrogen injection had three stages: gas expansion, rapid oxygen dilution, and complete inerting. The nitrogen injection effect presented a nonlinear change in injection location and flow rate. The optimal nitrogen injection location for the Tingnan Coal Mine in Shaanxi was determined to be 90 m behind the working face on the inlet side, with an optimal flow rate of 800 m3/min. This study focused on gas adsorption and offered valuable insights for creating high-efficiency fire-fighting techniques that involve inserting in the gob.


Assuntos
Minas de Carvão , Incêndios , Combustão Espontânea , Carvão Mineral , Adsorção , Incêndios/prevenção & controle , Minas de Carvão/métodos , Nitrogênio
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