Discharge Reactor Research Articles

Plasma characteristics and de-icing of three-electrode double-sided pulsed surface dielectric barrier discharge

Ice accumulation on aircraft can lead to aerodynamic performance degradation and even trigger security incidents. However, traditional surface dielectric barrier discharge (SDBD) reactors cannot work while covered by glaze ice. In the present work, a novel three-electrode double-sided SDBD is proposed and employed for glaze ice deicing. Compared with traditional SDBD reactor, three-electrode double-sided SDBD introduces an additional discharge area and grounding electrode. On one hand, the heat generated in the additional discharge area can melt the glaze ice covered on the high-voltage electrode, providing a discharge gap for the subsequent discharge. On the other hand, the introduction of the additional grounding electrode can also dramatically enhance the upper discharge and thermal effect. As a result, compared with the three-electrode single-sided SDBD and two-electrode double-sided SDBD, the three-electrode double-sided SDBD has the highest deposited energy, maximal temperature, and deicing rate. To further optimize the structural design, the effect of air gap length below the dielectric on three-electrode double-sided SDBD is investigated. And it is found that the best deicing performance can be obtained at the air gap length of 1 mm.

An Experimental Study on Direct Hydroxylation of Toluene in a Dielectric Barrier Discharge System Under Ambient Conditions

ABSTRACT Non-thermal plasma is a promising alternative to be utilized for the synthesis of hydroxytoluenes through one-pot hydroxylation of toluene. Direct preparation of hydroxytoluenes from vaporized toluene was conducted in air at room temperature and atmospheric pressure using a dielectric-barrier discharge (DBD) reactor. The preliminary results obtained from this study showed that cresols were formed along with benzaldehyde, benzyl alcohol, and phenol. O atoms generated by air plasma in collision with toluene produced OH and benzyl radicals, which led to further reactions. The mechanism of the reaction of reactive oxygen species (ROS) with toluene and toluene-derived radicals to yield the observed oxidation products was discussed.

Hydrogen generation by dielectric barrier discharge plasma assisted ammonia decomposition

Ammonia, which can serve as a hydrogen carrier for later dehydrogenation in zero-carbon hydrogen generation, is considered one of the key solutions. However, this solution is challenged by the high decomposition temperature and low reaction efficiency. In this paper, non-equilibrium plasma was used to effectively improve the reaction performance of ammonia decomposition to hydrogen and nitrogen using a dielectric barrier discharge reactor. Impacts of operating conditions including discharge parameters, diluted gases, and ammonia concentration on hydrogen generation were investigated. The ammonia decomposition breakdown voltage followed the order of 1 % ammonia/carbon dioxide (4000 V) > 1 % ammonia/nitrogen (3500 V) > 1 % ammonia/helium (1500 V) ≈ 1 % ammonia/argon (1500 V). The effect of pulse voltage and frequency is more significant on plasma-assisted ammonia decomposition compared to the pulse width. When the pulse frequency and width were 30 kHz and 100 ns at 298 K, the ammonia conversion reached 26.3 %, 34.1 % and 40.9 % at 5000, 7000, and 10000 V, respectively. With the addition of argon in 5 % ammonia/helium, the resulting penning effect makes the discharge easier and more uniform to promote ammonia decomposition. Furthermore, the kinetic analysis was investigated to better understand the conversion and utilization of ammonia in plasma-assisted reactions.

Experimental activities in view of hydrogen- deuterium equilibrium reaction in dielectric barrier discharge reactor: Effects of plasma treatment parameters and reactor design

Cryogenic distillation (CD) is a crucial process for separating and concentrating tritium in the tritium fuel cycle of fusion reactors. The equilibrator plays a vital role in decomposing HD, DT, and HT to improve the separation efficiency of hydrogen isotopes in CD. As the equilibrium reaction temperature decreases, a larger proportion of HD, HT, and DT decomposes into H2, D2, and T2, which enhances the performance of the equilibrator. While Pt/Al2O3 catalyst exhibits high activity at 303 K in the H2-D2 equilibrium reaction, it is almost inactive at 77 K. Non-thermal plasma (NTP) technology offers a promising and attractive alternative to conventional catalytic technology. In this study, H2-D2 equilibrium reaction was carried out without catalysts in a dielectric barrier discharge (DBD) reactor, achieving efficient conversion of HD even at 77 K. In the single-electrode DBD plasma reactor (S-P-Reactor), with an input power of 50 W, the conversion efficiency of HD was found to be 99.5% at 303 K, 99.5% at 273 K, and 99.2% at 77 K. To further optimize the energy efficiency of the S-P-Reactor, the reactor structure was enhanced, leading to the development of a multi-high-voltage DBD reactor (M-P-Reactor). The input power of the M-P-Reactor was reduced by approximately 10 W compared to the S-P-Reactor, while maintaining a conversion efficiency of over 95% for HD. The energy density of the reactor was calculated using the Q-V Lissajous graphic method, demonstrating that the M-P-Reactor exhibited superior energy conversion efficiency compared to the S-P-Reactor. Furthermore, the yield of HD was solely determined by the energy density and temperature. At a specific energy density, the yield of HD remained consistent for the same temperature. However, generating HD at lower temperatures required more energy due to the lower reactant activity. These results illustrate the potential application of NTP technology in improving hydrogen isotope separation performance in the cryogenic distillation process for fusion applications.

Holistic managements of textile wastewater through circular, greener and eco-innovative treatment systems developed by minimal to zero liquid discharge

New pragmatic and viable solutions to reduce or prevent discharge and to protect reserves are currently among the top-prioritised research for cleaner, circular, and resource-efficient use of industrial waters. So, the development of eco-sustainable water management is essential for green industrial development that will meet versatile and eco-sensitive regulatory standards, especially in water-intensive industries. Textile wastewater was reclaimed in semi to fully closed loops for minimal to zero liquid discharge. Concentrate-mixed wastewater was steadily treated in a hybrid membrane oxidation reactor at 60–80 % synergistic performances with remarkable UF fluxes of 96.4–820 L/m2h without any sludge discharge. Effluent was purified with 90–100 % removals and 20–80 L/m2h in nanofiltration and reverse osmosis. Due to Fenton-specific operation, more handling by ion exchange and neutralisation required to harvest membrane reuse waters and reactor discharge effluents with guaranteed Fe and pH. All-in-one system simulations indicated that high quality reuse waters are produced by 99.9 % efficiency and 98 and 100 % savings in iron and acid but 20–51 % more oxidant through concentrate recycling and regenerant reuse. It was also revealed that reactor effluents can be released to the sea or conventional biological treatment or can be eco-sustainably exploited for in-situ chemical and ex-situ bio-induced recovery of vivianite. This research demonstrates that how textile wastewater can be managed holistically by liquid discharge approaches from 50 % minimal to 99.9 % zero just in two-step, i.e. pretreatment and pre-concentration, with consumable minimisation and valuable waste recovery through the eco-innovative systems which are developed as circular, greener, and sludge-free compatible with sustainable development goals.

Computational Fluid Dynamic study of gas mixtures in a Non-Thermal Plasma reactor for CO2 conversion with Argon as diluent gas

CO2 utilization has been an emerging technology of increasing global interest due to its direct impact in limiting greenhouse gas emissions. In this contribution, the fluid dynamic behavior of a CO2 conversion non-thermal plasma (NTP) in a dielectric barrier discharge (DBD) reactor is studied through computational fluid dynamics (CFD) simulations.
 Calculations are provided in conjunction with experimental results and the thermodynamic characterization of the compounds and mixtures involved. This CFD study utilizes a well-established methodology that allows the optimization of fluid flow with limited computational burden.
 Firstly, results are presented for an Example Case, in which several variables are studied both at the final iteration as well as across iterations. Secondly, a range of Study Cases, changing the inlet composition and volume rate, are presented. Average velocity is one of the most significant variables to predict the reactor’s yield, while the temperature, density and pressure in the reactor remain, in most cases, almost constant.
 The resulting CFD computations describe the behavior of the fluids in the reactor in a predictive manner for future experimental results. Limitations in the fluid’s characterization occur due to not explicitly including the plasma reaction, which will be aimed at in future contributions.

Development of an Ir/TiO2 catalytic coating for plasma assisted hydrogenation of CO2 to CH4

The hydrogenation of CO2 to methane over a 20 wt% Ir/TiO2 catalytic coating has been investigated in a tubular dielectric barrier discharge (DBD) reactor. The 1.2 µm Ir/TiO2 coating was deposited onto the inner wall of a quartz tube by a combustion-evaporation method from a mixture containing a Ti precursor and a colloidal suspension of Ir nanoparticles (2 nm). The catalyst was characterised by XRD, SEM, TEM/EDS and CO chemisorption. The Ir(0) state in the as-synthesised film was confirmed by XPS. The CH4 conversion increased by 1.5 times, as compared to an empty tube. A maximum CO2 conversion rate of 2.1 μmol s−1 was achieved at a fuel production efficiency of 3.5%. Surface reactions onto the catalyst surface are responsible for enhancement of reaction rate. The results presented in this work open up new possibilities in plasma-catalysis, whereby efficient reactions can be carried out over small volumes of catalyst.

Ellipsoidal shaped Co3O4 quantum dots synthesis by atmospheric microplasma discharge: An electrochemical study

Spinel Co3O4 quantum dots (QDs) were synthesized for supercapacitor application using a customized plasma discharge reactor that generates stable non-equilibrium, high-density microplasma at ambient conditions. Microplasma, generated above the cobalt nitrate hexahydrate [Co(NO3)2·6H2O] solution using argon gas at 35 W discharge power, induced particle nucleation via high-energy electron collisions. High-resolution transmission electron microscopy (HR-TEM) images demonstrated that Co3O4 particles had an ellipsoidal morphology with an average size of 4 nm. Electrochemical investigation exhibited pseudocapacitive behavior, yielding a significant specific capacitance of 348.5 Fg−1 at 1 Ag−1 current density with a notable retention capacity in 1 M KOH electrolyte. These findings confirm Co3O4 QDs suitability as electrode material for supercapacitor applications.

Efficient catalyst-free N2 fixation by water radical cations under ambient conditions

The growth and sustainable development of humanity is heavily dependent upon molecular nitrogen (N2) fixation. Herein we discover ambient catalyst-free disproportionation of N2 by water plasma which occurs via the distinctive HONH-HNOH+• intermediate to yield economically valuable nitroxyl (HNO) and hydroxylamine (NH2OH) products. Calculations suggest that the reaction is prompted by the coordination of electronically excited N2 with water dimer radical cation, (H2O)2+•, in its two-center-three-electron configuration. The reaction products are collected in a 76-needle array discharge reactor with product yields of 1.14 μg cm–2 h–1 for NH2OH and 0.37 μg cm–2 h–1 for HNO. Potential applications of these compounds are demonstrated to make ammonia (for NH2OH), as well as to chemically react and convert cysteine, and serve as a neuroprotective agent (for HNO). The conversion of N2 into HNO and NH2OH by water plasma could offer great profitability and reduction of polluting emissions, thus giving an entirely look and perspectives to the problem of green N2 fixation.

Degradation and transformation of carbamazepine in aqueous medium under non-thermal plasma oxidation process

Carbamazepine (CBZ) is a pharmaceutical compound detected in various water resources. With a view to removing this contaminant, the applicability of non-thermal plasma (NTP) oxidation process has been widely tested in recent years. This study utilized NTP from a dielectric barrier discharge reactor in the treatment of CBZ. NTP on the surface of a water sample containing 25 mg.L−1 of CBZ resulted in a removal efficiency of over 90% with an energy yield of 0.19 g. (kWh)−1. On the other hand, a rapid reduction in pH and an increase of conductivity and nitrate/nitrite ions concentration were observed during the degradation. The applied voltage amplitude significantly affected the removal efficiency and the energy yield as the degradation efficiency was 55%, 70%, and 72% respectively with an applied voltage of 8, 10, and 12 kV. The water matrices containing inorganic anions such as chloride and carbonate ions reduced the removal efficiency by scavenging the reactive species. Accordingly, a reduction in the removal efficiency was observed in tap water. The high-resolution mass spectrometry (HRMS) results revealed that both reactive oxygen and nitrogen species take part in the reaction process which yields many intermediate products including aromatic nitro-products. This study concluded that NTP can effectively degrade CBZ in both pure and tap water, but special attention must be paid to changes in the water quality parameters (pH, conductivity, and nitrate/nitrite ions) and the fate of nitro products.

Efficient toluene degradation using Bacillus subtilis biofilm-supported Mn–Ce/zeolite catalysts

This study investigated a new approach for synthesizing Bacillus subtilis biofilm-supported Mn–Ce/zeolite catalysts for the degradation of gaseous toluene. Four different metal oxide nano-catalysts (ZMn, ZMnCe-10%, ZMnCe-20%, and ZMnCe-30%) were synthesized with varying ratios of manganese (Mn) and cerium (Ce) on zeolite nanoparticles. TEM, SEM, XRD, BET, XPS, and EDX mapping were used to examine these four samples, as well as simple zeolite. Based on these analyses, the catalytic activity of the prepared samples ZMn, ZMnCe-10%, ZMnCe-20%, and ZMnCe-30% for the complete oxidation of toluene and toluene intermediate products were tested with Non-thermal plasma (NTP) technology in a dielectric barrier discharge (DBD) reactor. Among all, ZMnCe-20% showed the highest toluene degradation efficiency (89%) at low concentrations (200 ​ppm) and humidity (>50%). Later, highly efficient and hydrophobic nano-biocatalysts were prepared by combining B. subtilis biofilm wild-type (WT) and engineered B. subtilis biofilm EPS with ZMnCe-20% catalyst. EPS is the main component found in biofilm matrix and plays a key role in influencing properties such as biofilm stability, electron transfer, surface roughness and hydrophobicity. Compared to WT B. subtilis biofilm, EPS overexpressed B. subtilis biofilm showed stronger growth and development on ZMnCe-20% nanocatalyst. Moreover, the NTP system packed with ZMnCe-20%/biofilm (EPS+) nano-biocatalyst exhibited the highest toluene degradation activity (99%) with (83%) CO2 selectivity, (up to 50%) reduction in NOx concentration and complete ozone decomposition at (250 ​ppm) toluene concentrations and increased humidity (>90%). High-energy electrons generated in the NTP system break the C–H and C–C bond between the rings of the toluene molecule, forming several byproducts which are later reacted with active radical species such as O, OH, and O3 and further converted into final degradation products (CO2 and H2O). The results demonstrated successful biofilm development and growth on the ZMnCe-20% catalyst with advanced features such as superhydrophobicity, H2O resistance, improved surface roughness, and electron generation. In short, the study's approach combines bioengineering and material science to develop sustainable nano-biocatalysts for removing VOCs in industrial and environmental settings.

Electrical characterization and imaging of discharge morphology in a small-scale packed bed dielectric barrier discharge

Packed bed dielectric barrier discharges (DBDs) exhibit an improved energy efficiency and selectivity in nonthermal plasma based gas conversion. They enable the direct interaction between plasma and catalyst. In this contribution a compact coaxial DBD reactor enabling the end-on imaging of the discharge with and without packed beds is studied. The discharge morphology is correlated with electrical measurements such as voltage-charge (V-Q) plots. The studies are performed for different packed bed materials, binary gas compositions of argon and carbon dioxide, voltage amplitudes, average powers, and pressures. The analysis points outs the role of parasitic capacitances and parasitic discharges as often overlooked aspects. The introduction of the packed bed material into the coaxial barrier discharge arrangement increases the total capacitance, but the barrier of the outer glass tube mostly determines the maximum effective dielectric capacitance. The choice of the packed bed material determines the voltage threshold and the average discharge power. The investigations leads to a revision of the equivalent circuit for packed bed barrier discharge reactors, which also accounts the properties of different filling materials.

Atmospheric–pressure DBD plasma modifying photoemission, optical and electrical properties of polycarbonate films

In this study, the DBD plasma reactor has been constructed, characterized, and tested to be employed in material treatment for use in different applications. A neon power source with an output of 10 kV, 30 mA, with a frequency of 20 kHz is used to drive the DBD reactor in an atmospheric-pressure environment. The investigation covered the analysis of many parameters of the dielectric barrier discharge (DBD) reactor, including its discharge voltage, current, capacitance, consumption energy, and the light emission of the produced plasma. Also, to examine the generated DBD plasma effect, the photoemission, optical, and electrical characteristics of untreated/treated polycarbonate films were investigated using photoluminescence spectroscopy, UV/Vis spectroscopy, and electrical spectroscopy. The results demonstrated the appearance of two modes in the DBD discharge: filamentary and homogeneous. Moreover, the DBD reactor's power consumption has been measured to be 20 mW at a supplied voltage of 6.5 kV peak-to-peak, operated in atmospheric–pressure. The photoluminescence emission results emphasized that the treated films are modified particularly with increasing DBD treatment time. The UV–Vis spectra demonstrated a notable displacement of the absorption edge towards higher wavelengths as the duration of DBD exposure increased. This is indicative of the reduction of the band gap energy, thus improving the electric conductivities. The optical parameters of the treated polycarbonate films were enhanced in comparison to the untreated sample. Through the used frequency range, measurements of dielectric loss, dielectric constant, as well as AC electrical conductivity, are sensitive parameters to the modifications in electrical behaviors due to DBD plasma treatment.

Optoelectronic Properties of Cold Plasma-Deposited, Oxidized Sn-C Thin Films.

We report on investigating the structural and electronic properties of semiconducting and insulating layers produced in a process resembling percolation in a unique cold plasma fabrication method (plasma-enhanced chemical vapor deposition-PECVD). Amorphous carbon-tin films (Sn-C) produced from tetramethyl tin (TMT) with an acoustic-frequency glow discharge in a three-electrode reactor were investigated. The layers, after air exposure, oxidized to SnO2/Sn-C. Depending on the coupling capacitance applied to the plasma reactor, the films could be obtained in the form of an amorphous semiconductor or an amorphous insulator. We assume that the semiconductor consists of an internal network of channels auto-organized during deposition. The insulator does not demonstrate any internal structure features. An investigation on conductive filaments creating low-dimensional (LD) nanojunctions in the semiconductor and the location of energetic levels in the insulator was performed. The main parameters of the electronic band structure of the insulating film, such as the transport gap EG (5.2 eV), optical gap Eopt (3.1 eV), electron affinity Χ (2.1 eV), and ionization potential J (7.3 eV), were determined. We have demonstrated a simple approach for developing a catalyst candidate consisting of amorphous semiconductor-insulator nanojunctions for (photo)catalytic hydrogen evolution or CO2 reduction.

Discharge characteristics of a microsecond pulsed underwater streamer discharge in multi-needle electrode configuration

The underwater streamer discharge has received extensive attention in the field of environmental protection, because it can generate free radicals and reactive oxygen species directly in water. The multi-needle electrode is a basic electrode configuration for achieving large-volume underwater streamer discharge. Understanding the discharge characteristics of the multi-needle electrode configuration is important for designing the large-volume discharge reactors. In this work, a multi-needle electrode that can assemble 21 needles is employed. The number of anode needles generating a streamer discharge during a single pulsed discharge and the differences in morphological characteristics between the inside and the edge of the electrode array are investigated by using an ultra-high-speed camera system. The electric field distribution of the multi-needle electrode is simulated by using the COMSOL software, and the effect of the electric field distribution on the discharge of multi-needle electrode is also studied. The discharge energy efficiency of the multi-needle electrode configuration is evaluated. It is found that the 21 needles are not discharged simultaneously during a discharge pulse. The number of discharged anode needles gradually increases and then reaches a maximum value (≤21). The maximum number of discharged anode needles during a single discharge pulse increases as the voltage and needle spacing increases. During a single discharge pulse, the filament generated from the needles at the edge of the electrode array grows longer and deviates more largely from the needle axis than that generated from the needles inside the electrode array. Such characteristics are primarily due to the disturbance of the electric field among the 21 needles. As the needle spacing decreases, the disturbance of the electric field among the 21 needles gets stronger, consequently, the discharge morphology differences between the needles at the edge and needles at the inner of the needle array become more significant, and the energy efficiency of the discharge drops remarkably.

Scenario optimization for the tokamak ramp-down phase in RAPTOR: Part B. safe termination of DEMO plasmas

An optimized plasma current ramp-down strategy is critical for safe and fast termination of plasma discharges in a tokamak demonstration fusion reactor (DEMO), both in planned and emergency scenarios, avoiding plasma disruptions and excessive heat loads to the first wall. Plasma stability limits and machine-specific technical requirements constrain the stable envelope through which the plasma must be navigated. Large amounts of auxiliary heating are required throughout the ramp-down phase, to avoid a radiative collapse in the presence of intrinsic tungsten and seeded xenon impurities, as quantitatively estimated in this work. As the plasma current is reduced, the current density becomes increasingly peaked, reflected by a growing value of the internal inductance ℓi3 , resulting in reduced controllability of the vertical position of the plasma. The feasibility of different plasma current ramp-down rates is tested by applying an automated optimization framework embedding the RAPTOR core transport solver. Optimal time traces for plasma current Ip(t) and plasma elongation κ(t) are proposed, to satisfy an Ip -dependent upper limit on the plasma internal inductance, as obtained from vertical stability studies using the CREATE-NL code, as well as a constraint on the time evolution of q 95, to avoid an ideal MHD mode. A negative current density near the plasma edge is observed in our simulations, even for the most conservative Ip ramp-down rate, indicating significant transient dynamics due to a large resistive time.

Degradation of n-hexane by the high-throughput double dielectric barrier discharge: Influencing factors, degradation mechanism and pathways

The emission of volatile organic compounds (VOCs) is known to be a source of various environmental problems. N-hexane is a saturated aliphatic hydrocarbon that is a major precursor of ozone. For the decomposition of n-hexane, a novel double dielectric barrier discharge (DDBD) reactor design is developed and tested on a pilot scale. The factors influencing the plasma degradation of n-hexane have been thoroughly investigated. The degradation efficiency, carbon balance and nitrogen oxide concentration were measured and analysed. Through experiments, it was found that the maximum removal of n-hexane at an initial concentration of 2000 ppm and a flow rate of 5 L/min was 1544 ppm. The associated energy efficiency reached 67.71 ppm/J. The excited states of oxygen and nitrogen (O2+, O(3 s5S-3p5P), N2(C3Πu-B3Πg), N2+(B2Σu+-X2Σg+)) during n-hexane degradation were observed. Possible degradation pathways of n-hexane are proposed, and it is revealed that the active species play an important role in the formation of oxygen and nitrogen-containing volatile organic by-products. The results show that the pilot-scale design of the DDBD system provides a feasible way for the industrial treatment of n-hexane, and provides fundamental insights into the mechanism of plasma catalytic system operation.

Pulsed Dielectric Barrier Discharges for Gas-Phase Composition Control: A Simulation Model

We present results obtained from the numerical simulation of the gas-phase chemical kinetics in atmospheric pressure air non-equilibrium plasmas. In particular, we addressed the effect of the pulsed operation mode of a planar dielectric barrier discharge. As conjectured, the large difference in the time scales involved in the fast dissociation of molecules in plasmas and their subsequent reactions to produce stable chemical species makes the presence of a continuously repeated plasma production stage unnecessary and a waste of electrical power and efficiency. The results on NOx remediation, ozone production, water vapor and ammonia dissociation are discussed. A few comparisons with experimental findings in a dielectric barrier discharge reactor already used for applications are also briefly addressed. Our results clearly indicate a pattern for the optimization of the discharge using a carefully designed repetition rate and duty cycle.

Enhancement of VOCs removal using a novel double‐tube packed bed catalytic dielectric barrier discharge (DPDBD) reactor

AbstractWe developed a novel double‐tube packed bed catalytic dielectric barrier discharge (DPDBD) reactor to degrade toluene. The DPDBD reactor contains four discharge cells with one power supply, namely, A–D. NiO/γ‐Al2O3 is packed in cell A to effectively destroy the branched chains in toluene. TiO2/γ‐Al2O3 is packed in cell B owing to its high catalytic oxidation activity to weaken the benzene rings and mineralize the generated partial aromatic compounds. Cell C is a pure DBD process without any catalyst packed to thoroughly mineralize all the generated aromatic compounds and convert CO into CO2 and NO into NO2. γ‐Al2O3 is packed in cell D to reduce the concentrations of byproducts, including O3 and NO generated by air through oxidation. The combinations of the four discharge cells are optimized by the treatment of −3000 mg m−3 of toluene at 11 kV. In comparison with a double‐tube dielectric barrier discharge (DDBD) reactor without catalyst packing and with a total discharge length of 6 cm, the selectivity of CO2 was significantly improved from 45% to 57% when the discharge lengths of A, B, C, and D are 2, 4, 4, and 2 cm, respectively. Furthermore, the concentrations of O3 and NO in the outlet can also be effectively reduced from 2.80 and 210 mg m−3 to 1.30 and 60 mg m−3, respectively. We also investigated the effects of applied voltage and styrene initial concentration.

Red mud and foundry sand industry wastes for reducing NOx in plasma activated diesel exhaust

Solid waste in association with plasma was explored as an alternate to commercial catalyst/adsorbents. We have demonstrated reuse of foundry sand and red mud wastes for adsorption of gaseous pollutant from plasma treated diesel exhaust. A novel dielectric barrier discharge reactor with dual metal film is designed to explore the oxidation potential of surface discharge plasma effect onto the exhaust. The metal film was subjected to high voltage pulse/AC energization to assess the effect of plasma in oxidising NO to NO2. A separate reactor filled with industry wastes was cascaded with plasma reactor to test its efficacy in NO2 adsorption. It was observed that some amount of NO was also reduced owing to some visible light-enabled photocatalytic activity. About 85 % NOx (oxides of nitrogen) reduction was observed with red mud waste compared to half of that with foundry sand.