Removal of VOCs at trace concentration levels from humid air by Microwave Swing Adsorption, kinetics and proper sorbent selection

Nigar, Hakan; Navascués, Nuria; Iglesia, Óscar de la; Mallada, Reyes; Santamarı́a, Jesús

doi:10.1016/j.seppur.2015.07.019

Cited by 55 publications

(25 citation statements)

References 31 publications

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“…The CO 2 desorption curves under conventional and microwave heating are presented in Figures a,b, together with the evolution of temperature and normalized occupancy (Figure c) of the sorbent. The kinetic analysis showed that, even though under conventional heating the highest available heating ramp was attempted (20 K/min) desorption using 60 W microwave heating is approximately three times faster. The faster regeneration provided by MW heating also results in a higher CO 2 concentration in the sweep gas, with peak concentrations that are roughly double under MW heating for each amino‐functionalized sample, compared to the values obtained under conventional heating.…”

Section: Resultsmentioning

confidence: 99%

“…This problem could be solved using the volumetric and selective heating afforded by microwaves. In a previous work of our laboratory, we showed a reduction in desorption time of 75% using MW‐heatable zeolites as sorbents of n‐hexane . On the other hand, the desorption of CO 2 by microwaves from zeotypes (zeolite X and ETS‐10) 6, and carbon has been recently reported.…”

Section: Introductionmentioning

confidence: 87%

“…The fixed bed adsorption and desorption experiments were performed in an experimental setup previously described which consisted of three mass flow controllers, two automatic four‐way valves, and an on‐line quadrupole mass spectrometer (OMNIstar), MS, for the analysis of the gases. The experimental system was computer‐controlled by a Labview customized program.…”

Section: Methodsmentioning

confidence: 99%

“…Carbon materials are good microwave absorbers as a consequence of the interactions of delocalized π‐electrons with MWs, thus converting MW energy into heat . In the case of zeolites, a different heating mechanism has been found related to the interaction of the electromagnetic field with, (i) the water or polar molecules adsorbed in the pores, (ii) the hydroxyl groups on the surface, and (iii) the cation movement in the structure.…”

Section: Introductionmentioning

confidence: 99%

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Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating

et al. 2015

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WileyNigar, H.; García-Baños, B.; Penaranda-Foix, FL.; Catalá Civera, JM.; Mallada, R.; Santamaria, J. (2016). Amine-functionalized mesoporous silica: A material capable of CO2 adsorption and fast regeneration by microwave heating. AIChE Journal. 62 (2) The surface of ordered mesoporous (MCM-48) silica has been subjected to covalent grafting with silane molecules containing one to three amino groups. The dielectric properties of the materials were studied in detail, and the functionalized materials were used for CO 2 adsorption at room temperature, followed by regeneration under either conventional heating or microwave irradiation. It has been found that, as the intensity of functionalization with amino groups increases (from mono to tri-amino silanes) both the CO 2 load and the dielectric response at microwave frequencies increase. In particular, functionalization with a tri-amino silane derivative gave the highest CO 2 adsorption and the fastest microwave heating, resulting in a 4-fold acceleration of adsorbent regeneration. The grafted material was fully stable for at least 20 adsorption-regeneration cycles, making it an ideal candidate for microwaveswing adsorption (MWSA) processes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating

et al. 2015

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“…The best performances were gained with the DAY zeolite (Si/Al = 40), that showed an excellent combination of adsorption capacity and microwaves interaction efficiency [203]. Furthermore, in 2018 they also developed a microwave-heated adsorbent reactor in order to realize a continuous cleaning system for air streams with n-hexane low concentrations [204].…”

Section: Volatile Organic Compound (Voc) Removalmentioning

confidence: 99%

Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

et al. 2020

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Since the late 1980s, the scientific community has been attracted to microwave energy as an alternative method of heating, due to the advantages that this technology offers over conventional heating technologies. In fact, differently from these, the microwave heating mechanism is a volumetric process in which heat is generated within the material itself, and, consequently, it can be very rapid and selective. In this way, the microwave-susceptible material can absorb the energy embodied in the microwaves. Application of the microwave heating technique to a chemical process can lead to both a reduction in processing time as well as an increase in the production rate, which is obtained by enhancing the chemical reactions and results in energy saving. The synthesis and sintering of materials by means of microwave radiation has been used for more than 20 years, while, future challenges will be, among others, the development of processes that achieve lower greenhouse gas (e.g., CO 2 ) emissions and discover novel energy-saving catalyzed reactions. A natural choice in such efforts would be the combination of catalysis and microwave radiation. The main aim of this review is to give an overview of microwave applications in the heterogeneous catalysis, including the preparation of catalysts, as well as explore some selected microwave assisted catalytic reactions. The review is divided into three principal topics: (i) introduction to microwave chemistry and microwave materials processing; (ii) description of the loss mechanisms and microwave-specific effects in heterogeneous catalysis; and (iii) applications of microwaves in some selected chemical processes, including the preparation of heterogeneous catalysts.A chemical process is conventionally energized by means of conductive heating with a steam boiler as a typical heat source. Nevertheless, a large variety of other forms of energy can be applied for PI, including ultrasounds (for reactions or crystal nucleation), light (in photocatalytic processes), electric fields (in extraction or for orientation of molecules), or microwaves. The microwave (dielectric) heating of materials has been known for a long time, and microwave ovens have been developed from more than 60 years. The studies by Gedye et al. in 1986 and 1988 [3,4] opened a period of very intensive investigation of the microwave effects on chemical reactions in homogeneous systems. Since then, hundreds of research papers have been published, and research has also expanded toward heterogeneous catalysis and its related chemical processes. This review gives an overview of the application of microwave technology to heterogeneous catalysis, including various chemical processes, as well as to the preparation of catalysts.

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Sol–Gel Synthesis of High‐Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption

Hunter‐Sellars

Sáenz-Cavazos

Houghton

et al. 2020

Adv Funct Materials

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Monolithic ZIF-8 and ZIF-67 adsorbents are synthesized at room temperature using a novel, ligand-assisted method. Despite reductions in crystallinity within some of the samples, monolithic zeolitic imidazolate frameworks (ZIFs) have superior volume-relative microporosity, total porosity, and surface areas relative to their particulate counterparts due to increased density. Samples synthesized using a single modulator, n-butylamine, have a hierarchical porosity resulting in improved adsorption capacities in mid-to high-sorbate pressure regions. ZIF-67 monoliths produced through mixedmodulator synthesis, n-butylamine and 1-methylimidazole, are almost entirely microporous. Vapor adsorption isotherms find that, whilst their amorphous content results in increased water uptake, monolithic ZIFs are found to possess higher surface and adsorption hydrophobicity than traditional nonpolar adsorbents. Cosorption measurements with a common VOC toluene, under humid conditions, find that these monolithic ZIF samples outperform powder equivalents, with the mixed-modulator ZIF-67 monolith capturing 28% more VOC compared to the powder ZIFs studied due to its superior volumetric efficiency. This study provides insights into the benefits of modulator-based tuning of porosity within monolithic ZIFs which, combined with their hydrophobicity, may facilitate their application for industrial organic vapor recovery or indoor air cleaning, where efficient hydrophobic adsorbents which can operate in humid environments are essential.

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Removal of VOCs at trace concentration levels from humid air by Microwave Swing Adsorption, kinetics and proper sorbent selection

Cited by 55 publications

References 31 publications

Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating

Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating

Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

Sol–Gel Synthesis of High‐Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption

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Removal of VOCs at trace concentration levels from humid air by Microwave Swing Adsorption, kinetics and proper sorbent selection

Cited by 55 publications

References 31 publications

Amine‐functionalized mesoporous silica: A material capable of CO2 adsorption and fast regeneration by microwave heating

Amine‐functionalized mesoporous silica: A material capable of CO2 adsorption and fast regeneration by microwave heating

Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

Sol–Gel Synthesis of High‐Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption

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Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating

Amine‐functionalized mesoporous silica: A material capable of CO₂ adsorption and fast regeneration by microwave heating