Microwave dielectric heating: Applications on metals processing

Khaled, Dalia El; Novas, Nuria; Gázquez, José Antonio; Manzano‐Agugliaro, Francisco

doi:10.1016/j.rser.2017.10.043

Cited by 153 publications

(65 citation statements)

References 98 publications

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“…The CFRP waste experiments were carried out in a high-temperature microwave furnace with a frequency of 2.45 GHz, under an oxygen atmosphere. In general, industrial microwave frequency is 2.45 GHz or 915 MHz [27,36]. However, most of the experiments regarding materials [27,28,37,38], metallurgical properties [27,30], or food [36,39] processing by microwaves are based on microwave magnetrons with 2.45 GHz frequency [28].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…Therefore, research to develop new methods of recovering carbon fibers from CFRP has begun.Microwave heating is gradually being used more often in the area of material processing due to its advantages of rapid, uniform, and selective heating [26]. Microwave heating is the process of coupling materials with microwaves, absorbing electromagnetic energy and transforming it into heat within the material volume, in which the heat is generated from the inside to the entire volume [27][28][29]. Therefore, the microwave method can treat uniform samples due to its features of volumetric and internal heating [30,31].…”

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Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Deng

Zhang

et al. 2019

Processes

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With the growth of the use of carbon fiber-reinforced polymer (CFRP) in various fields, the recovery of carbon fibers from CFRP waste is becoming a significant research direction. In the present work, degrading epoxy resin and recycling carbon fibers from CFRP waste by microwave thermolysis and traditional thermolysis were studied. The carbon fibers were successfully recovered by thermolysis under an oxygen atmosphere in this study. The properties of the recovered carbon fibers were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy. The result shows that using microwave thermolysis to recover carbon fibers from CFRP waste is an attractive prospect. Compared to the traditional method, the reaction time was reduced by 56.67%, and the recovery ratio was increased by 15%. Microwave thermolysis is faster, more efficient, requires less energy, and obtains cleaner recovered carbon fibers than those recovered using traditional thermolysis.Processes 2019, 7, 207 2 of 12 including mechanical processes [14,15], chemical methods [4,[16][17][18][19][20], and thermal technology [3,[21][22][23]. However, long carbon fibers are difficult to obtain using a mechanical process, and their mechanical properties are seriously damaged with this technique [24,25]. Liu et al. [13], Yildirir et al. [19], and Hyde et al. [20] have investigated recycling carbon fibers from CFRP using different solvents under subcritical or supercritical conditions. These methods are expensive, difficult to industrialize, and produce large amounts of liquid waste and hazardous gases [1]. Yang et al. [3], López et al. [22], and Ye et al. [23] have studied thermolysis methods of recovering carbon fibers from CFRP. The pyrolysis process is not very economical, producing multiple hazardous gases and depositing char on the carbon fiber surfaces [1,19,25]. Therefore, research to develop new methods of recovering carbon fibers from CFRP has begun.Microwave heating is gradually being used more often in the area of material processing due to its advantages of rapid, uniform, and selective heating [26]. Microwave heating is the process of coupling materials with microwaves, absorbing electromagnetic energy and transforming it into heat within the material volume, in which the heat is generated from the inside to the entire volume [27][28][29]. Therefore, the microwave method can treat uniform samples due to its features of volumetric and internal heating [30,31]. Yingguang Li et al. [32,33] have reported curing of CFRP by microwave energy, and CFRP can absorb microwave energy and be heated effectively. This study provides a great reference for microwave applications in the preparation and recovery of CFRP. Long Jiang et al. [34] reported that microwave irradiation is a flexible, easy-to-control, efficient method to recover high-value carbon fibers, and recovered carbon fibers could be directly used as reinforcement in new polymers (Polypropylene and nyl...

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Section: Materials and Experimental Proceduresmentioning

confidence: 99%

mentioning

confidence: 99%

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Deng

Zhang

et al. 2019

Processes

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“…It is now clear how microwave heating is fundamentally different from the conventional conduction-based heating, since when microwaves penetrate the material to supply energy, heat is generated in the whole volume and "volumetric heating" occurs ( Figure 3). Volumetric heating minimizes the processing time, lowers the consumption of power and improves the diffusion rate: microwave heating is attractive from the PI point of view [16].…”

Section: Of 58mentioning

confidence: 99%

“…Catalysts 2020, 10, x FOR PEER REVIEW 7 of 59 consumption of power and improves the diffusion rate: microwave heating is attractive from the PI point of view [16].…”

Section: Of 58mentioning

confidence: 99%

“…Differently from the electric field heating, there are not many papers ascribing the microwave heating effect to the magnetic field (H) component. In the paper by El Khaled et al, some interesting results on studies carried out to verify the effect of the magnetic field in the microwave heating were reported [16]. In particular, (i) the studies of Cheng et al, published in the first years of the twentieth century, proved that some magnetic dielectric materials are more efficiently heated by the microwave magnetic field rather than the electric field; (ii) the studies by Zhiwei et al, published in 2012, gave a relevant importance to the magnetic component of the electromagnetic field and presented its main advantages over electric field heating described earlier in a larger number of publications.…”

Section: Microwave Heating Due To the Magnetic Fieldmentioning

confidence: 99%

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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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MoS₂/Graphene Composites as Promising Materials for Energy Storage and Conversion Applications

Wang

Tran

Qian

et al. 2019

Adv Materials Inter

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Energy storage devices with high performance have been extensively studied for decades due to the increasing fuel demands. The physicochemical properties of 2D materials such as MoS 2 and graphene, due to their high surface area, versatile electronic structure, high mechanical robustness, This article is protected by copyright. All rights reserved. 2 high electrical conductivity, and desirable electrochemical characteristics, make them superior candidates for energy storage applications. MoS 2 /graphene composites specially emerge as exceptional candidates that could offer new solution for energy storage applications. Many fabrication strategies to develop and synthesize MoS 2 /graphene composites have been explored and introduced, such as hydrothermal and solvothermal treatment, chemical vapor deposition, sonication, microwave and self-assembly. For these composites to be suitable for energy storage devices applications, they are often integrated with other materials such as additional agents to improve their electrochemical and stability properties. In this review, recent progresses on the development of graphene/MoS 2 composites for energy storage and conversion applications (supercapacitors, batteries, solar cells, and hydrogen evolution) is presented and discussed. Critical review and perspectives on the future directions for MoS 2 /graphene composite based energy storage devices are also presented as concluding remarks. Recent progress on the development of graphene/MoS 2 composites for energy storage applications is also presented and discussed.

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Microwave dielectric heating: Applications on metals processing

Cited by 153 publications

References 98 publications

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

MoS₂/Graphene Composites as Promising Materials for Energy Storage and Conversion Applications

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Microwave dielectric heating: Applications on metals processing

Cited by 153 publications

References 98 publications

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

MoS2/Graphene Composites as Promising Materials for Energy Storage and Conversion Applications

Contact Info

Product

Resources

About

MoS₂/Graphene Composites as Promising Materials for Energy Storage and Conversion Applications