Energy Conversion Phenomena Research Articles

Study of the Effect of Exciton Annihilation Lifetime on Some Kinematic and Intrinsic Parameters of a Silicon Heterojunction Solar Cell (HIT), Illuminated by Monochromatic Light

In this article, with a view to improving the efficiency of photovoltaic cells, and given the promising yields of silicon heterojunction photovoltaic cells, we have, using a silicon heterojunction cell (a-Si:H/c-Si) doped with (n+p) , studied the contribution of excitons to the internal quantum efficiency of charge carriers. We then developed a detailed explanation of the energy conversion phenomena, based on an exciton-exciton annihilation process, which allows the electrons of quasiparticles to retain some of their energy. We used a numerical method for solving the charge carrier transport equations and carried out some additional calculations, which enabled us to obtain some results. These results then enabled us to study the influence of the annihilation lifetime on the charge carrier photo-current density, leading to internal charge carrier quantum yields of between 29.29768% and 77.8525%.

Lie group analysis and SQLM of entropy generation of MHD nonlinear radiative micropolar nanofluid flow with thermophoresis and Brownian motion

This study investigates the entropy generation in hydromagnetic mixed convection of a micropolar fluid flowing over a stretchable sheet, taking into account various influential factors such as nonlinear thermal radiation, Ohmic dissipation, uniform heat source/sink effects, chemical reaction, thermophoresis, and Brownian motion. The Spectral Quasilinearization Method (SQLM) is employed, which transforms nonlinear equations into a series of linearized ones, streamlining the solving process. Additionally, Lie group analysis is utilized to identify symmetries and derive similarity transformations crucial for converting partial differential equations into coupled ordinary differential equations, which are then solved numerically. A comprehensive sensitivity analysis is conducted on critical parameters, including the Darcy parameter, Biot number, Brinkman number, nonlinear convection parameter, and chemical reaction parameter. This analysis explores the impacts of these parameters on various flow profiles, such as velocity, temperature, microrotation, concentration, and entropy generation, enriching the depth and practical relevance of the findings. The results reveal that increasing the Brinkman and Reynolds numbers enhances entropy generation profiles while increasing the coupling parameter reduces them. The focus on entropy generation analysis provides valuable insights into energy utilization and system efficiency, particularly in micropolar fluid dynamics. Furthermore, the study underscores the practical implications of its findings by highlighting their relevance in evaluating the effectiveness of industrial processes, especially those related to energy conversion and heat transfer phenomena.

Numerical analysis of semiconductor-based energy conversion technologies for offshore applications

This study analyzes the physical principles and characteristics of thermoelectric energy conversion phenomena utilizing p-n semiconductor couples to propose a design methodology for thermoelectric generators (TEGs) capable of energy recovery in marine environments. To design TEGs with practical power generation and energy conversion efficiency, the development of a numerical analysis model that can predict and analyze the behavior characteristics of TEGs is required. We present the necessary conditions for a numerical analysis model that simulates the generation characteristics of TEGs at the system level, along with a comparison and analysis of experimental results. The electrical connection method of the thermoelectric modules (TEMs) significantly affects the power generation performance of TEGs; however, there is a lack of research on the electrical connections between TEMs in existing studies. This paper examines the reasons for performance changes due to electrical connections between TEMs and proposes an optimal electrical connection method. Additionally, it is demonstrated that improving the thermal flow distribution within the TEG can enhance system performance and maximize the effects of electrical connections between TEMs. We analyze the characteristics of technologies that can improve the level of thermal flow distribution within the TEG, such as finned and porous structures, and present optimal utilization strategies.

Molecular layer deposition to grow a luminescent metalorganic monolayer on inorganic substrate: Breaking monopoly of solution routes to self-assembled monolayer

A gas-phase route such as molecular layer deposition has been applied for the first time to create a monolayer of metalorganic Eu(III) molecules on NiO oxide layer. The surface of the as-deposited NiO layer is activated using H2O/O2 vapors, and then functionalized by anchoring molecules of the Eu complex working at different temperatures to favor the chemisorption process. The effects of the activation process and of the MLD temperature on the chemisorption of the Eu complex were evaluated through in-depth X-ray photoelectron and luminescence spectroscopy studies. These analyses allowed to define the stoichiometry of the Eu moiety chemisorbed on the surface and the optimization of an impressive strategy to the synthesis of hybrid metalorganic/inorganic systems. The hybrid system's luminescence properties have proved the monolayer's energy conversion phenomena and produced further information about the local environment around the Eu(III) anchored as a complex on the NiO surface.

Advances in Organic Thermoelectric Devices for Multiple Applications

AbstractOrganic thermoelectric (OTE) devices composed of π‐conjugated molecules are the basic building blocks for self‐powered integrated organic electronics. In addition to molecular design and doping strategies, the highly tunable energy conversion process in OTE devices has drawn significant research interest. Specifically, the diverse physical properties of organic semiconductors, novel device geometry design, and advanced fabrication techniques combined enable the OTE device to be a powerful multiscale platform from single‐molecular scale to thin films for modulating the TE performance, studying the fundamental charge transport mechanism, exploring novel energy conversion phenomenon, and realizing various functionalities. Here, the authors comprehensively review the recent experimental and theoretical advances in related topics of OTE devices, including multifunctional, external physical fields, and temperature modulated, as well as quantum OTE devices. The remaining issues and perspectives toward future OTE device research are also discussed at the end.

Comparative Study on NACA-9405, NACA-9503 and NACA-9506 Airfoil Profiled Blade Open-Channel Flow Cross-Flow Turbine

Several agricultural areas in Indonesia are classified as underdeveloped rural areas, and challenging to acquire electricity from the primary grid. On the other hand, some pico hydropower potentials can be found in agriculture, especially at the irrigation dam spillway flows. However, no such technology can convert the energy inside the water open-channel flow through dam spillways into electricity. Crossflow turbines (CFT) are expected to utilize dam spillways’ power due to their ability to convert the kinetic energy of water. Prior studies found that airfoil profile could slightly increase CFT efficiency and affect the interaction between water and turbine. Using planar two-dimensional computational fluid dynamics (CFD) numerical simulation analysis, the current study investigated the energy conversion phenomenon inside different open-channel CFT blade profiles. This study simulates CFT working at 3 meters of total head and 0.04 m3/s of water discharge put into the dam spillway’s downstream. The turbine blade profiled with the National Advisory Committee of Aeronautics (NACA) standard airfoil numbered 9405, 9503, and 9506 are being compared and investigated in the present study. CFD numerical analysis results show that the forward direction NACA airfoil profiled blades deliver better efficiency than the reversed one. These findings contradict the prior study’s results which tested airfoil profiled CFT working as usual with nozzle. This phenomenon indicated differences in the energy transfer process between open channel CFT and the ordinary CFT with a nozzle. Furthermore, current work finds that forward NACA-9503 CFT has a higher efficiency than other tested airfoil profiles, with 57.05% efficiency. In addition, the present study finds that the NACA-95XX airfoil has a more suitable chamber curve with the original CFT blade’s curve than the NACA-94XX airfoil by velocity triangle analysis. Then, the NACA-9503 profile is thinner than the NACA-9506 profile, which eases water flowing through the turbine blades.

Three-zone numerical modeling method for predicting system-level waste heat recovery performance of thermoelectric generator with various electrical array configurations

In this study, an experimentally validated numerical model is formulated to accurately predict the energy harvesting performance of a thermoelectric generator (TEG) by reflecting the underlying physics of the thermoelectric energy conversion phenomena. The most advantageous feature of the modeling method employed herein is its high reliability because the system-level performance is predicted based on module-level power generation characteristics. A further benefit that the proposed physics-based model affords is that the effect of electrical array configurations (i.e., the particular manner by which the thermoelectric modules (TEMs) are electrically connected) on the waste heat recovery performance of the TEG can be accurately predicted. For this purpose, a three-zone modeling method, wherein each TEM is modeled into heat sink, heat generation, and heat conduction zones, is proposed. Moreover, user-defined functions are embedded into the numerical model to correlate the temperature fields obtained from the transport of momentum and energy with the Seebeck effect and Joule heating that appear as the thermoelectric output power and heat sink/heat generation near the TEM surface. The accuracy and reliability of the numerical model are validated by the experimental results of temperature and output power using a TEG prototype whose configurations and dimensions are identical to those of the proposed numerical model. Further comparisons between the numerical results obtained using eight different electrical array configurations and the corresponding experimental results ensure the robustness of the modeling method and numerical model formulated in this study. Finally, two correlations are derived as a function of the number of electrical array branches to predict the output voltage and current of a TEG whose branches consist of an identical number of TEMs for minimizing unexpected power losses.

Integrated hybrid of graphitic carbon-encapsulated CuxO on multilayered mesoporous carbon from copper MOFs and polyaniline for asymmetric supercapacitor and oxygen reduction reactions

Hybrid electrode materials composed of metal-organic framework (MOF)-derived oxides and conducting polymers have abundant potential for energy applications. The energy storage and conversion phenomena of such materials are due to their high porosity, long stability, good conductivity, low charge transport resistance, and fast charge-discharge rate. Herein, CuxO-C/PANI is synthesized by the in situ polymerization of aniline on multilayered mesoporous CuxO-C from Cu-MOF. Such an integrated hybrid can provide a potential route for electron transfer and improve the kinetics of redox reactions. Subsequently, the CuxO-C/PANI composite demonstrates a maximum specific capacitance of 1308 F g−1 at 1 A g−1 in a 3-electrode system. Additionally, as a fabricated device, CuxO-C/PANI//ZIF-8NPC shows an uppermost energy density of 55.1 W h kg−1 (at a 862.4 W kg−1 power density) and power density of 8668.2 W kg−1 (at a 30.1 W h kg−1 energy density), with 88.3% capacitance retention, even after 10000 cycles. Additionally, CuxO-C/PANI, as an efficient oxygen reduction catalyst, delivers an outstanding onset potential (0.94 V) and half-wave potential (0.76 V) against the reversible hydrogen electrode with good stability. Hence, these results show that the as-fabricated electrode material is an efficient alternative electrocatalyst for energy storage and oxygen reduction applications.

Spray-Coated Thin-Film Ni-Oxide Nanoflakes as Single Electrocatalysts for Oxygen Evolution and Hydrogen Generation from Water Splitting.

Electrochemical water splitting is a key process in many electrochemical energy conversion and storage phenomena. Simple synthesis methods to make highly porous and active nanostructured catalytic materials with large electroactive surface areas are very important to implement water-to-fuel conversion schemes. Herein, ultrafine, transparent thin-film nickel-oxide (NiOx) nanoflakes are facilely synthesized following a simple spray-coating method from a solution-phase precursor. The NiOx nanoscale structures are grown on the FTO surface in the form of highly uniform smooth thin films. They are employed as promising bifunctional electrocatalysts for the overall water splitting process under alkaline conditions. During water oxidation catalysis, NiOx-SC/FTO initiates the oxygen evolution reaction (OER) at an overpotential η of just 250 mV while generating current decade at just 300 mV and demonstrates well-balanced kinetics toward OER. 10 mA cm–2 current density remains persistent for many hours of continuous electrolysis at just 1.53 VRHE illustrating high robustness of the system. The catalyst also showed substantial activity and durability toward the hydrogen evolution reaction (HER) under the same electrochemical conditions. Tafel slopes of just 57 and 89 mV dec–1 for OER and HER in 0.5 M aqueous KOH solution, respectively, showing high intrinsic kinetics for electrocatalysis. Having high electrochemical surface area and an optimum number of electrochemically active sites, these transparent NiOx thin films can be advantageously combined with photoelectrochemical devices for light-driven water-to-fuel conversion systems.

Thermoacoustic energy conversion in a square duct

The present study aims to demonstrate the thermoacoustic energy conversion phenomenon in a standing wave resonator driven by a commercial loudspeaker with a stack made of plastic straws and atmospheric air as the working fluid. The system is driven at resonance frequency of 70 Hz with the stack kept in the middle section of the resonator and a temperature difference of 14.1℃ was produced between the ends of the stack at a drive ratio of 3.57 %. The hot end reached a temperature of 36.5℃ and the cold end reached a temperature of 22.4℃ at the highest drive ratio. Moving the stack towards the end of the resonator reduces the temperature difference produced showing the influence of stack position. Thermoacoustic devices offer an environment-friendly solution to utilize waste heat or renewable energy sources, to upgrade low grade heat or generate cooling or produce electricity using acoustic-electric transducers. This study is done as a pre-cursor, to develop a relatively inexpensive prototype for studying non-linear effects at high drive ratios seen in thermoacoustic devices, which are known to reduce their performance.

Intrinsic energy conversions for photon-generation in piezo-phototronic materials: A case study on alkaline niobates

The creations of photons in response to mechanical stimulus in a crystal that has noncentral symmetry are the great fundamental physics responsible for numbers of important technologies. The underlying mechanism and complete theory for a precise explanation of the mechanical-photonic energy conversion phenomena is vital important. We take commercial piezoelectric LiNbO3 matrics as the example to interpret the detail mechanisms of energy conversions for the photon-generation through a native point defects study. It was found the Frenkel and Schottky type complex pairs as well as the antisite pair defects acting as energy harvesting and migration centers, which are very easy to form and active. It does to be the extra deep electron or hole traps levels near the valence or conduction band edge, respectively. That is the substantial energy reduction via a spontaneous equilibrium transformation from the complementarily charged individuals into agglomerated complexes. Such energy gain for both two processes turns to be independent to the variations of synthesis chemical potentials. In addition, the complex defects actually form independent to the variations of the chemical potentials. This leads to a coupling and exchange effect by them to continuously collect and transport host charges along the path via localized states to the deep recombination levels. The initiating energy barrier is small which ambient thermal stimulation or quantum tunneling can accomplish. The native sensitizers such as VNb2O5, VLiNbO3, NbLi are also the energy conversion centers to non-radiative resonant energy transfer onto the activator center at the Oi to transfer the energy into photon emissions. A generalized energy conversion mechanism has been unraveled in this work. This gives a solid theoretical reference for developing the mechanical-photonic energy conversion materials.

Magnons and Phonons Optically Driven out of Local Equilibrium in a Magnetic Insulator

The coupling and possible nonequilibrium between magnons and other energy carriers have been used to explain several recently discovered thermally driven spin transport and energy conversion phenomena. Here, we report experiments in which local nonequilibrium between magnons and phonons in a single crystalline bulk magnetic insulator, Y_{3}Fe_{5}O_{12}, has been created optically within a focused laser spot and probed directly via micro-Brillouin light scattering. Through analyzing the deviation in the magnon number density from the local equilibrium value, we obtain the diffusion length of thermal magnons. By explicitly establishing and observing local nonequilibrium between magnons and phonons, our studies represent an important step toward a quantitative understanding of various spin-heat coupling phenomena.

Electric Field Induced Reversible Phase Transition in Li Doped Phosphorene: Shape Memory Effect and Superelasticity.

Phosphorene, the single-layer form of black phosphorus, as a new member of atomically thin material family, has unique puckered atomistic structure and remarkable physical and chemical properties. In this paper, we report a discovery of an unexpected electromechanical energy conversion phenomenon-shape memory effect-in Li doped phosphorene P4Li2, using ab initio density functional theory simulations. Two stable phases are found for the two-dimensional (2D) P4Li2 crystal. Applying an external electric field can turn on or off the unique adatom switches in P4Li2 crystals, leading to a reversible structural phase transition and thereby the shape memory effect with an tunable strain output as high as 2.06%. Our results demonstrate that multiple temporary shapes are attainable in one piece of P4Li2 material, offering programmability that is particularly useful for device designs. Additionally, the P4Li2 displays superelasticity that can generate a pseudoelastic tensile strain up to 6.2%. The atomic thickness, superior flexibility, excellent electromechanical strain output, the special shape memory phenomenon, and the programmability feature endow P4Li2 with great application potential in high-efficient energy conversion at nanoscale and flexible nanoelectromechanical systems.

Structural design and functional bionic of nano carbon composites

With unique structure and excellent properties, nano carbon composites like carbon nanotube (CNT) and graphene (GE), have become research focus in nano technology and nano materials, and promoted the rapid development of multifunctional nanocomposites since their discovery. However, with traditional preparation method, the volume of nanometer carbon content in composite materials can only reach 5%–10% due to nanoparticles aggregation and rheological properties of resin, etc. Different from a small amount of nano carbon reinforced polymer composites, nano carbon composites with high concentrations can better exhibit the properties of nano materials, with more advantages in stress transfer, higher shear and tensile breaking strength, have attracted more and more attention in research and applications for these years. With the development of new nano carbon composite materials, more requirements about the structure design and functional development of materials were put forward. The structure of nano carbon units and their arrangement, uniform dispersion and interfacial interaction are extremely important to performances of composite materials. Traditional way can optimize orientation degree and improve packing density but it is still not enough, such as stretching can effectively improve the mechanical and electrical properties of materials, but cannot fundamentally solve the aggregation phenomenon of nanometer unit, performance of conversion efficiency in nano unit is still low. Fortunately, the nature provided us a new clue on the design of high performance and multifunctionalities of nano carbon materials. Structure and interface bonding composites in the organism are both strong and tough. Therefore, nano carbon composite materials of bionic structure are one of the important development directions in the future, and have got the attention of the researchers. In addition, the bionic structure and interface on the energy conversion phenomena, can also realize the function of the composite material bionic, making the nano carbon composite materials have perception, adaptive, self-driven bionic multi-functional characteristics, etc. First, based on traditional processing methods, we obtained the further optimization of carbon nanotubes orientation degree through bionic processing, with good control of aggregation in high volume content of carbon nanotube composites. Second, the rich interface bonding mechanism in laminated shell structure was found, and a hard and soft material with a certain strength and toughness was prepared. Third, on the basis of functional bionics, more abundant sensing and response forms of the smart drive, stronger response ability, more expansive functional applications were achieved. Therefore, learning from the nature, rationalization of structure, excellent performances, controllability and highly efficient applications of which have been achieved by structural design and integration of ideas. And this biomimic method has become an important direction of nano composites. While we still have many things to do in nano carbon composite materials with this approach and lack a deep understanding of the transformation mechanism between biological structure and function. In this paper, we have reviewed the preparation and processing of high content nano carbon composites and their bionic design of structure and interface. Also the progress in applications of bionic smart drive was introduced. In the end, we discussed the development direction of multifunctional nano carbon composites.

Energy Conversion Mechanics for Photon Emission per Non-Local Hidden-Variable Theory

Problem-Energy conversion processes in optical phenomena are incompletely explained by wave theory or quantum mechanics. There is a need for ontologically rich explanations at the level of individual particles. Purpose: This paper reports on the application of a non-local hidden-variable solution called the Cordus theory to this problem. The method is directed to the systematic development of a conceptual framework of proposed causal mechanisms. Findings: It has long been known that the bonding commitments of the electron affect its energy behaviour but the mechanisms for this have been elusive. We show how the degree of bonding constraint on the electron determines how it processes excess energy. A key concept is that the span and frequency of the electron are inversely proportional. This explains why energy changes cause positional distress for the electron. Natural explanations are given for multiple emission phenomena: Absorbance; Saturation; Beer-Lambert law; Colour; Quantum energy states; Directional emission; Photoelectric effect; Emission of polarised photons from crystals; Refraction effects; Reflection; Transparency; Birefringence; Cherenkov radiation; Bremsstrahlung and Synchrotron radiation; Phase change at reflection; Force impulse at reflection and radiation pressure; Simulated emission (Laser). Originality: The paper elucidates a mechanism for how the electron responds to combinations of bonding constraint and pumped energy. The crucial insight is that the electron size and position(s) are coupled attributes of its frequency and energy, where the coupling is achieved via physical substructures. The theory is able to provide a logically coherent explanation for a wide variety of energy conversion phenomena.

Strain-based scanning probe microscopies for functional materials, biological structures, and electrochemical systems

Strain and electromechanical coupling are ubiquitous in nature, and exist in many processes involved in information technology, energy conversion, and biological phenomena. Strain-based scanning probe microscopy (s-SPM) techniques, especially piezoresponse force microscopy (PFM) and electrochemical strain microscopy (ESM), have emerged as powerful tools to probe and manipulate materials, structures, and systems at the nanoscale. In this review, we will present the fundamentals of s-SPM and a variety of its operational modes, introduce its applications in scientifically or technologically important functional materials, electrochemical systems, and biological structures, and discuss some of its challenges and potential opportunities. By detecting dynamic strains associated with underlying microscopic processes excited by a scanning probe, high sensitivity and unprecedented spatial resolution can be obtained, though caution must be exercised to distinguish different microscopic mechanisms, and quantitative interpretation of the s-SPM data remains challenging. We expect that s-SPM will continue to provide great insight into functional materials and structures, and will play a valuable role in the emerging field of materiomics.

Integrative self-sorting: a versatile strategy for the construction of complex supramolecular architecture.

Large protein-sized synthetic supramolecular architecture is rare and certainly has not yet achieved the structural and functional complexity of biomolecules. As multiple, identical copies of a few building blocks are repetitively used, a highly symmetrical architecture results with limitations in function. In marked contrast, functional structures in nature are often assembled with high geometric precision from many different building blocks. They cooperate in a complex way realizing energy conversion, mechanical motion or transport phenomena. Beyond self-assembly, the structurally and functionally complex biomolecular machines rely on self-sorting to correctly position all subunits through orthogonal recognition sites. Mimicking such self-sorting processes is a promising strategy for supramolecular synthesis - resulting in higher structural complexity and promising access to a more sophisticated function. The term "integrative self-sorting" was coined to describe the strategy to form well-defined assemblies with well-controlled subunit positions. The key process is the incorporation of two or more orthogonal binding motifs into at least some of the subunits. Modularity and programmability based on orthogonal yet similar binding motifs generate diversity and complexity. Integrative self-sorting is thus inherently related to systems chemistry. Depending on the individual binding motifs, (multi-)stimuli responsiveness can be achieved. When different recognition events en route to the final assembly occur on significantly different time scales, kinetic pathway selection is observed. In this account, we review the modularity, programmability, and emergent properties of integrative self-sorting, emphasizing its utility and perspective for complex supramolecular architectures.

Bio-Mimetics of Disaster Anticipation-Learning Experience and Key-Challenges.

Simple SummaryStarting from 1700 B.C. in the old world and up to recent times in China there is evidence of earthquake prediction based on unusual metrological phenomena and animal behavior. The review tries to explore the credibility and to pin down the nature of geophysical phenomena involved. It appears that the concept of ancient Greek philosophers in that a dry gas, pneuma is correlated with earthquakes, is relevant. It is not the cause of earthquakes, as originally thought, but may be an accompanying phenomenon and occasional precursor. This would explain unusual animal behavior as well as thermal anomalies detected from satellites.Anomalies in animal behavior and meteorological phenomena before major earthquakes have been reported throughout history. Bio-mimetics or bionics aims at learning disaster anticipation from animals. Since modern science is reluctant to address this problem an effort has been made to track down the knowledge available to ancient natural philosophers. Starting with an archaeologically documented human sacrifice around 1700 B.C. during the Minoan civilization immediately before a large earthquake, which killed the participants, earthquake prediction knowledge throughout antiquity is evaluated. Major practical experience with this phenomenon has been gained from a Chinese earthquake prediction initiative nearly half a century ago. Some quakes, like that of Haicheng, were recognized in advance. However, the destructive Tangshan earthquake was not predicted, which was interpreted as an inherent failure of prediction based on animal phenomena. This is contradicted on the basis of reliable Chinese documentation provided by the responsible earthquake study commission. The Tangshan earthquake was preceded by more than 2,000 reported animal anomalies, some of which were of very dramatic nature. They are discussed here. Any physical phenomenon, which may cause animal unrest, must involve energy turnover before the main earthquake event. The final product, however, of any energy turnover is heat. Satellite based infrared measurements have indeed identified significant thermal anomalies before major earthquakes. One of these cases, occurring during the 2001 Bhuj earthquake in Gujarat, India, is analyzed together with parallel animal anomalies observed in the Gir national park. It is suggested that the time window is identical and that both phenomena have the same geophysical origin. It therefore remains to be demonstrated that energy can be released locally before major earthquake events. It is shown that by considering appropriate geophysical feedback processes, this is possible for large scale energy conversion phenomena within highly non-linear geophysical mechanisms. With satellite monitored infrared anomalies indicating possible epicenters and local animal and environmental observations immediately initiated, the learning experience towards an understanding of the phenomena involved could be accelerated.

Microscopic energy conversion process in the ion drift region of electrohydrodynamic flow

We theoretically investigated the momentum transfer and energy conversion process of ion-neutral and ensuing neutral-neutral collisions in the ion drift region of electrohydrodynamic flow. Our results are presented in explicit equations with physical interpretations of the phenomena. The unit conversion process was estimated to sustain for 1.0 nano-second in a very tiny 0.5-μm-sized volume in the air. Also, the continuum-based equation formulations are presented according to the microscopic energy conversion phenomena. Numerical simulations reflecting those formulations are performed to verify the theoretical results and experimentally supported by an air corona discharge.

About using microwave irradiation in competitive adsorption processes

The use of microwave radiation for improving adsorption selectivity towards some species in co-adsorption processes is investigated. The microwave effect is evaluated and discussed at a microscopic level based on a set of co-adsorption experiments conducted with various zeolites (NaX, NaY, DAY, NaA) and using two different couples of adsorbates contrasted in polarity: H2O/CO2 and H2O/Toluene. These experiments conducted without heating, under microwave or conventional thermal heating, demonstrate that microwaves do not affect co-adsorption equilibrium by another manner than the thermodynamic effect. Temperature is the controlling parameter of the adsorption equilibrium and adsorption selectivity is identical as soon as the same temperature is reached, independently of the heating system which is used. Nevertheless, temperature heterogeneity, often obtained under microwaves, can be a way of improving selectivity and co-adsorption processes. Simulations of the temperature bed distribution under microwave irradiation have been made for particular zeolite bed configurations. The model accounts for the electromagnetic wave propagation coupled to energy conversion and heat transfer phenomena. From these results, a new process combining several adsorbent beds of contrasted selectivity towards species and of different dielectric properties is proposed. It uses microwave regeneration taking advantage of the temperature heterogeneity. It is a way to obtain energy efficient adsorption processes and high purity adsorbate recovery.