Probing the impact of material properties of core-shell SiO2@TiO2 spheres on the plasma-catalytic CO2 dissociation using a packed bed DBD plasma reactor

This work proposes to use core-shell structured spheres to evaluate whether it allows to individually optimize bulk and surface effects of a packing material, in order to optimize conversion and energy efficiency. Different core-shell materials have been prepared by spray coating, using dense spheres (as core) and powders (as shell) of SiO2, Al2O3, and BaTiO3. The materials are investigated for their performance in CO2 dissociation and compared against a benchmark consisting of a packed-bed reactor with the pure dense spheres, as well as an empty reactor. The results in terms of CO2 conversion and energy efficiency show various interactions between the core and shell material, depending on their combination. Al2O3 was found as the best core material under the applied conditions here, followed by BaTiO3 and SiO2, in agreement with their behaviour for the pure spheres. Applying a thin shell layer on the cores showed equal performance between the different shell materials. Increasing the layer thickness shifts this behaviour, and strong combination effects were observed depending on the specific material. Therefore, this method of core-shell spheres has the potential to allow tuning of the packing properties more closely to the application by designing an optimal combination of core and shell.

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Plasma Catalytic Conversion of CH4 to Alkanes, Olefins and H2 in a Packed Bed DBD Reactor

Processes ◽

10.3390/pr8070774 ◽

2020 ◽

Vol 8 (7) ◽

pp. 774

Author(s):

Mohammadreza Taheraslani ◽

Han Gardeniers

Keyword(s):

Barrier Discharge ◽

Plasma Reactor ◽

Packed Bed ◽

Reaction Pathways ◽

Ambient Conditions ◽

Alumina Catalyst ◽

Dbd Plasma ◽

Hydrogenation Reactions ◽

Notable Increase

Methane is activated at ambient conditions in a dielectric barrier discharge (DBD) plasma reactor packed with Pd/γ-alumina catalyst containing different loadings of Pd (0.5, 1, 5 wt%). Results indicate that the presence of Pd on γ-alumina substantially abates the formation of deposits, leads to a notable increase in the production of alkanes and olefins and additionally improves the energy efficiency compared to those obtained for the non-packed reactor and the bare γ-alumina packed reactor. A low amount of Pd (0.5 and 1 wt%) favors achieving a higher production of olefins (mainly C2H4 and C3H6) and a higher yield of H2. Increasing Pd loading to 5 wt% promotes the interaction of H2 and olefins, which consequently intensifies the successive hydrogenation of unsaturated compounds, thus incurring a higher production of alkanes (mainly C2H6 and C3H8). The substantial abatement of the deposits is ascribed to the role of Palladium in moderating the strength of the electric and shifting the reaction pathways, in the way that hydrogenation reactions of deposits’ precursors become faster than their deposition on the catalyst.

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High-Resolution SEM and EDX Characterization of Deposits Formed by CH4+Ar DBD Plasma Processing in a Packed Bed Reactor

Nanomaterials ◽

10.3390/nano9040589 ◽

2019 ◽

Vol 9 (4) ◽

pp. 589 ◽

Cited By ~ 3

Author(s):

Mohammadreza Taheraslani ◽

Han Gardeniers

Keyword(s):

High Resolution ◽

Elemental Analysis ◽

Morphological Changes ◽

Plasma Reactor ◽

Packed Bed ◽

Amorphous Structure ◽

Dielectric Surface ◽

Packed Bed Reactor ◽

Lower Amount ◽

Dbd Plasma

The deposits formed during the DBD plasma conversion of CH4 were characterized by high-resolution scanning electron microscopy (HRSEM) and energy dispersive X-ray elemental analysis (EDX) for both cases of a non-packed reactor and a packed reactor. For the non-packed plasma reactor, a layer of deposits was formed on the dielectric surface. HRSEM images in combination with EDX and CHN elemental analysis of this layer revealed that the deposits are made of a polymer-like layer with a high content of hydrogen (60 at%), possessing an amorphous structure. For the packed reactor, γ-alumina, Pd/γ-alumina, BaTiO3, silica-SBA-15, MgO/Al2O3, and α-alumina were used as the packing materials inside the DBD discharges. Carbon-rich agglomerates were formed on the γ-alumina after exposure to plasma. The EDX mapping furthermore indicated the carbon-rich areas in the structure. In contrast, the formation of agglomerates was not observed for Pd-loaded γ-alumina. This was ascribed to the presence of Pd, which enhances the hydrogenation of deposit precursors, and leads to a significantly lower amount of deposits. It was further found that the structure of all other plasma-processed materials, including MgO/Al2O3, silica-SBA-15, BaTiO3, and α-alumina, undergoes morphological changes. These alterations appeared in the forms of the generation of new pores (voids) in the structure, as well as the moderation of the surface roughness towards a smoother surface after the plasma treatment.

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Removal of sulfur dioxide from air using a packed-bed DBD plasma reactor (PBR) and in-plasma catalysis (IPC) hybrid system

Environmental Science and Pollution Research ◽

10.1007/s11356-021-13173-5 ◽

2021 ◽

Author(s):

Niloofar Damyar ◽

Ali Khavanin ◽

Ahmad Jonidi Jafari ◽

Hassan Asilian Mahabadi ◽

Ramazan Mirzaei ◽

...

Keyword(s):

Sulfur Dioxide ◽

Hybrid System ◽

Plasma Reactor ◽

Packed Bed ◽

Plasma Catalysis ◽

Dbd Plasma

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Coupling of CH4 to C2 Hydrocarbons in a Packed Bed DBD Plasma Reactor: The Effect of Dielectric Constant and Porosity of the Packing

Energies ◽

10.3390/en13020468 ◽

2020 ◽

Vol 13 (2) ◽

pp. 468 ◽

Cited By ~ 5

Author(s):

Mohammadreza Taheraslani ◽

Han Gardeniers

Keyword(s):

Dielectric Constant ◽

Strong Electric Field ◽

Plasma Reactor ◽

Packed Bed ◽

Ambient Conditions ◽

Dbd Plasma ◽

Low Dielectric ◽

Small Pore ◽

High Dielectric ◽

C2 Hydrocarbons

The conversion of methane was investigated in a packed-bed dielectric barrier discharge (DBD) plasma reactor operated at ambient conditions. High dielectric BaTiO3 was utilized as packing in comparison with γ-alumina, α-alumina, and silica-SBA-15. Results show a considerably lower conversion of CH4 and C2 yield for the BaTiO3 packed reactor, which is even less than that obtained for the nonpacked reactor. In contrast, the low dielectric alumina (γ and α) packed reactor improved the conversion of CH4 and C2 yield. Additionally, the alumina packed reactor shifted the distribution of C2 compounds towards C2H4 higher than that obtained for the nonpacked reactor and resulted in a higher energy efficiency compared to the BaTiO3 packed reactor. This is attributed to the small pore size of BaTiO3 (10–200 nm) and its high dielectric constant, whereas the polarization inside small pores does not lead to the formation of an overall strong electric field.

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Synergetic Effect of Packed-bed Corona-DBD Plasma Micro-Reactor and Photocatalysis for Organic Pollutant Degradation

Separation and Purification Technology ◽

10.1016/j.seppur.2021.118728 ◽

2021 ◽

pp. 118728

Author(s):

Ainy Hafeez ◽

Nasir Shezad ◽

Fahed Javed ◽

Tahir Fazal ◽

Muhammad Saif ur Rehman ◽

...

Keyword(s):

Organic Pollutant ◽

Synergetic Effect ◽

Packed Bed ◽

Pollutant Degradation ◽

Dbd Plasma ◽

Organic Pollutant Degradation ◽

Micro Reactor

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A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽

10.3390/ma14112784 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2784

Author(s):

Georgios Maliaris ◽

Christos Gakias ◽

Michail Malikoutsakis ◽

Georgios Savaidis

Keyword(s):

Process Parameters ◽

Material Properties ◽

Shot Peening ◽

Qualitative Assessment ◽

Experimental Investigations ◽

Elastoplastic Material ◽

Size Distributions ◽

User Friendly ◽

The Impact ◽

2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

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CdSe/ZnS Core-Shell-Type Quantum Dot Nanoparticles Disrupt the Cellular Homeostasis in Cellular Blood–Brain Barrier Models

International Journal of Molecular Sciences ◽

10.3390/ijms22031068 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1068

Author(s):

Katarzyna Dominika Kania ◽

Waldemar Wagner ◽

Łukasz Pułaski

Keyword(s):

Gene Expression ◽

Quantum Dot ◽

Blood Brain Barrier ◽

Protein Gene ◽

Brain Barrier ◽

Core Shell ◽

Cellular Homeostasis ◽

Blood Brain ◽

Shell Type ◽

The Impact

Two immortalized brain microvascular endothelial cell lines (hCMEC/D3 and RBE4, of human and rat origin, respectively) were applied as an in vitro model of cellular elements of the blood–brain barrier in a nanotoxicological study. We evaluated the impact of CdSe/ZnS core-shell-type quantum dot nanoparticles on cellular homeostasis, using gold nanoparticles as a largely bioorthogonal control. While the investigated nanoparticles had surprisingly negligible acute cytotoxicity in the evaluated models, a multi-faceted study of barrier-related phenotypes and cell condition revealed a complex pattern of homeostasis disruption. Interestingly, some features of the paracellular barrier phenotype (transendothelial electrical resistance, tight junction protein gene expression) were improved by exposure to nanoparticles in a potential hormetic mechanism. However, mitochondrial potential and antioxidant defences largely collapsed under these conditions, paralleled by a strong pro-apoptotic shift in a significant proportion of cells (evidenced by apoptotic protein gene expression, chromosomal DNA fragmentation, and membrane phosphatidylserine exposure). Taken together, our results suggest a reactive oxygen species-mediated cellular mechanism of blood–brain barrier damage by quantum dots, which may be toxicologically significant in the face of increasing human exposure to this type of nanoparticles, both intended (in medical applications) and more often unintended (from consumer goods-derived environmental pollution).

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