Papers by Keyword: Dielectric Barrier Discharge

Abstract: In this study, the performance of dielectric barrier discharge (DBD) integrated with the aerobic process with the input voltage of 20 and 25 kV on the production of biogas; methane (CH₄), hydrogen (H₂), and carbon dioxide (CO₂) from palm oil mill effluent (POME) were investigated. The DBD and DBD integrated with the aerobic process (DBD + aerobic) treatment was also simulated using the theoretical stoichiometric of POME (in terms of carbohydrate) and the kinetic study using the first- and second-order kinetic model. The results showed only 0.58, 0.39, and 0.97 mol/L of CH₄, H_2, and CO₂, respectively, generated from the simulation model, which underperformed those experimental results. This may be due to the low concentration of carbohydrates given by the simulated stoichiometric reaction. However, both simulation and experimental results showed a rapid increase in biogas concentration in the initial reaction time in the DBD + aerobic reactor with an input voltage of 25 kV. The results showed that DBD + reactor produced CH₄, H_2, and CO₂ thirteen, twenty-three, and three times higher than DBD alone, respectively. This suggests that good performance was observed when the DBD was integrated with the aerobic process under the optimum input voltage. The study can give information on the optimum condition in a lab scale to produce CH₄, H_2, and CO₂ from POME.

Abstract: The functionalization of polyester fabric (PES) with antimicrobial agents presents huge number of potential applications in advanced products. However, the lack of functional groups and the high PES hydrophobicity make the functionalization processes costly, prolonged and requires the use of polluting chemicals compounds. In this work, dielectric barrier discharge (DBD) plasma treatment, an affordable and environmental-friendly method, was used to introduce new chemical groups, increase the surface energy and roughness of PES in order to improve the adhesion of silver nanoparticles (AgNPs) in its surface. The PES functionalization was evaluated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and antimicrobial efficacy against Staphylococcus aureus and Escherichia coli. Despite some additional oxidation, the DBD plasma-treated PES showed superior adhesion of AgNPs and excellent antimicrobial efficacy even after 10 washing cycles (WC).

Abstract: In this paper, the emission spectra of the atmospheric N₂ and N₂/CO₂ DBD plasma being processed by PP sample are analyzed. The results indicate the spectrum lines of oxygen atoms ion (O⁺) in the region of 382.1 nm - 389.3 nm and 412.1 nm - 421.3 nm are observed in N₂ plasma. However, the spectrum lines of O⁺ has absolutely disappeared, furthermore the γ spectrum band of NO in the region of 270nm-325nm has appeared in N₂/CO₂ plasma because the metastable nitrogen molecules () are quenched by CO₂ molecules. This causes that the collision of the metastable nitrogen molecules () and PP sample surface were reduced and ultimately leads to a reduction in the treatment effect of the N₂/CO₂ plasma on the surface of the PP sample. Therefore, this indicates the metastable nitrogen molecules () in the plasma region plays a key role in improving the characteristics of the PP surface.

Abstract: In this study, the principal possibility of methane formation from syngas (the mixture of hydrogen and carbon monoxide) in the dielectric barrier discharge plasma was shown. The results of syngas conversion under microsecond pulses (amplitude up to 12 kV and frequency of 1000Hz) treatment in the five-tube reactor were discussed. The dependence of the methane formation on the volume flow rate and the energy input were studied. Also effect of inert gases (by the example of nitrogen) addition in the initial gaseous mixture on the methane formation was investigated.

Abstract: Plant source-based stiff fiber reinforced bioplastics based on natural plant derived substances show promise of providing degradation back into the environment when they are no longer needed. These "green" composites have enormous potential to replace materials originated from non-renewable resources and may turn out to be one of the material revolutions of this century. Unlike synthetic composites, "green" composites are renewable, carbon neutral, biodegradable, non-petroleum based, and have low environmental, human health and safety risks. In this paper effect of pineapple leaf fiber (PALF) length and physical surface treatment on to the properties of the composites was investigated at 10% wt. loading. In order to improve compatibility and composite properties of PALF/poly (lactic acid) composites without any hazardous chemicals that are usually involved in the process, dielectric barrier discharge (DBD) plasma surface treatment was conducted for fiber modification. Therefore more environmentally friendlier and industrially scalable technology was implemented in processing of composites by twin screw extrusion and injection moulding. Resulted composites were characterized by means of scanning electron microscopy (SEM), thermal and mechanical testing.

Abstract: Influence of plasma dielectric barrier discharge on oligomerization of carbon monoxide was shown. The ratio of CO and H₂ was equal to 2: 1. Gas flow-rate was 3 cm³/s for H₂ and 6 sm³/s for CO. It was found that methane formation is 1.2% at parameters of dielectric barrier discharge of 0.1 J. per pulse, up to 2000 pulse per second.

Abstract: This paper is focused on the processing of thermoplastic composite materials obtained from carbon fibers (CFs) treated by plasma assisted techniques. The treatments employed in this work were the Dielectric Barrier Discharge (DBD), which is done at atmospheric pressure, involving lower energies and the Plasma Immersion Ion Implantation (PIII), which is performed at low pressure, involving higher energies. After the treatments, samples characterizations were performed to determine which treatment is most effective to get better physico-chemical CF surface properties. The techniques employed in this work in order to evaluate the surface treatment were: scanning electron microscopy (SEM); atomic force microscopy (AFM) Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). Treated and untreated CFs/Polyphenylene sulfide (PPS) composites were processed by hot-compression molding technique. These composites were evaluated by interlaminar shear tests (ILSS). After analyzing the results, it was found that the treatments increased the CF roughness and caused slight changes in the CF structure. In addition, there was an increase in the shear strength of the composites obtained from treated fibers by both plasma processes. In conclusion, DBD and PIII treatments are effective tools for improving adhesion between CF and the polymeric matrix.

Abstract: A simple composite bonding that combines dielectric barrier discharge (DBD) plasma activation with anodic bonding has been developed to achieve strong silicon/glass bonding at low temperature. The realization of low temperature bonding is attributed to enhance the hydrophilicity and smooth of silicon and glass surfaces and form lots of free radical after the DBD plasma (including-OH, -H, O, and heat) reacts with the interfaces. And these further reduce the difficulty of chemical bond switching, and improve the speed of the intimate contact formation. The experimental result show that the bonding temperature strongly decreased 100°C by using composite anodic bonding with DBD pretreatment which strength kept constant, and 10MPa bonding strength was obtained at 250°C/900V after the bonding interface was treated for 10s under the conditions of AC1.5KV/25KHz and the clearance 100μm.

Abstract: The toluene being removed by dielectric barrier discharge (DBD) combined with modified photocatalyst was studied in the paper. Transition metal manganese was doped into crystal lattice of TiO₂ in order to improve the activity of photocatalyst, and the optimal doping ratio was confirmed in the study. As one of main factors, the influence on toluene removal efficiency of gas flow rate, initial concentration and electric field intensity was analyzed in the study. Furthermore, the energy efficiency was another important index which had been compared amongγ-Al₂O₃, TiO₂/γ-Al₂O₃ and Mn-TiO₂/γ-Al₂O₃. The result of study showed that DBD combined with Mn-TiO₂/γ-Al₂O₃ had the best buffer action against increasing of gas flow rate and initial concentration, the energy efficiency had the tendency as Mn-TiO₂/γ-Al₂O₃ > TiO₂/γ-Al₂O₃>γ-Al₂O₃, and the optimal doping ratio of manganese was 0.01.

Abstract: The low-temperature plasma technology has the comprehensive action of high-energy electron, ultraviolet light, ozone etc. The technology that integrates light, electronic and chemical oxidation into one process has a good development prospect in wastewater treatment. In this paper, the research status and development trend of high-voltage pulsed discharge, dielectric barrier discharge, glow discharge for organic wastewater treatment at home and abroad are summarized. The current main existing problems include single treatment object oriented. In the future, the study about this technique should be focused on the optimization process, the reduction of the processing cost and energy consumption, so that this technology can be applied to practical wastewater treatment as soon as possible.Key words: Low temperature plasma technology; High-voltage pulsed discharge; Glow discharge; Dielectric barrier discharge; Wastewater