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This work reports an investigation of the discharge characteristics of atmospheric dielectric barrier discharge (DBD) plasma in terms of I-V curves and Lissajous figures and their effect on the surface functionalities of electrospun silk/PVA nanofibers. The results show that the filamentary discharge is predominant at lower electrode gap (3 mm) and then significantly reduces at higher electrode gaps of 6 mm and 10 mm, respectively and in the applied voltage range of 11–17 kV. The silk/PVA nanofibers which are treated with 6 mm electrode gap shows good wettability, higher surface energy, higher tensile strength, young’s modulus values and improved anti-thrombogenic property. All these findings suggest that, although the silk/PVA nanofiber itself can be used in biomedical applications however, nanofibers plasma treated at 6 mm electrode gap shows better results in terms of physical and biological performances.

The plasma-chemical hybrid process (PCHP) has been effectively employed for the simultaneous removal of NOx and SOx in combustion gases. In this study, a PCHP-based semi-dry-type desulfurization reactor was developed for high-temperature exhaust gas from a glass melting furnace with a 10-MW-class thermal input. The NO in the exhaust gas is oxidized to NO2 by ozone generated from scale-up dielectric barrier discharge-based plasma ozonizers with a total input power of 77 kW and total ozone generation of 10 kg/h. SO2 reacts with NaOH solution in the semi-dry reactor to produce Na2SO3, which further reacts with NO2 to reduce NOx to N2. The produced Na2SO4 is in the form of dry particles and can be collected and reused in glass manufacturing. The exhaust gas at the outlet of the semi-dry reactor is maintained between 200 and 250 °C to protect the dry-type electrostatic precipitator. A localized cooling area is created by spraying cooling water, which is necessary to prevent the thermal decomposition of ozone and to spray an efficient aqueous solution for achieving dry conditions at the reactor outlet. Simultaneous desulfurization and denitrification were tested at low glass-production rates by injecting adequate flow rates of ozone for NO removal. Optimal removal efficiencies of 45 and 39% were obtained for NO and NOx, respectively. More than 90% of the byproducts were recovered in the form of Na2SO4. The designed facility with the semi-dry-type PCHP was confirmed to be highly effective and promising for exhaust gas treatment in glass manufacturing.

The objective of the study was to investigate the bactericidal effectiveness of atmospheric pressure nonthermal plasma (NTP) on biofilms of Staphylococcus aureus and Escherichia coli formed on the surface of surgical sutures. Tests were carried out for polyamide nonabsorbable monofilament sutures and mid-term absorbable synthetic monofilament sutures made of glyconate. Dielectric barrier discharge reactor providing atmospheric air plasma and constant discharge power density of 70 mW/cm2 was used in the experiments. The colonization/decontamination efficacy was quantified by colony-counting assay. It was shown that decontamination efficacy of the studied surgical sutures was time-dependent i.e. the effect was more visible for longer exposure times ranging from 60 to 360 s. It was proposed to combine plasma treatment with washing the biofilms with a phosphate buffered saline to to allow the plasma to interact with cells in the deeper layers of bacterial biofilm. The application of the original method of treatment of biofilms was more effective than the separate plasma treatment. As a result, the lethal effect was most often achieved after 300 s regardless of the type of suture and biofilm. The results of the comparative studies on the decontamination efficiency of polymeric surgical suture surface by disinfectants and NTP technique have shown unequivocally that plasma treatment is the most effective way to deactivate bacterial cells and ensures a lethal effect for most of the tested cases.

A miniaturized flow device has been developed to combine microfluidics technology and plasma process. In this microreactor, atmospheric pressure dielectric barrier discharges are generated in a gas in contact with a liquid phase. This study was conducted with plasma generated in ammonia in contact with a flow of liquid cyclohexane. Cyclohexylamine was synthesized with a good selectivity, and the process can be implemented to improve conversion and effectiveness. Numerical simulations confirmed that NH2 radicals are generated in the plasma and react with cyclohexyls radicals to achieve the reaction, giving a selectivity of 50% and a total molar conversion of 20% of cyclohexane. The effects of voltage and frequency on the selectivity and the experimental conversion rate were studied and discussed.

Over the years, the combined Non-thermal Plasma (NTP) denitrification process which is used for decomposition of NOx has have become an application technology with great potential. And the formation of byproducts, such as N2O and O3, which is an important factor that interfere with NO removal efficiency, has a high research value. In present study, HZSM-5 molecular sieve was selected as the packed material in dielectric barrier discharge reactor to investigate the effect of reaction conditions, such as with/without packed bed, discharge power, inner electrode diameter, electrode shape and operation time, on formation and conversion characteristics of byproducts (N2O and O3). Results showed that the presence of HZSM-5 pellets in discharge zone increases the discharge power, NO removal efficiency and the concentration of the byproducts in the outlet. The optimization of electrode diameter and the utilization of screw thread electrode increased the NO removal efficiency and the yield of N2O and O3. The pellets temperature increases with the operation time and the enhancement of input energy, which has different effects on O3 and N2O. These results provide some new methods for improving the NTP-assisted catalytic denitrification process.

Plasma-photocatalysis system (PPS) constructed by dielectric barrier discharge and TiO2 photocatalysts could realize toluene oxidation removal at low temperatures, but requires further enhancement in the performance due to the relatively poor activity of TiO2. We herein report that co-loading Ag and CeO2 on porous TiO2 can construct a active Ag–CeO2/TiO2 photocatalyst for the PPS, enabling the PPS to achieve promoted toluene conversion, CO2 selectivity and stability in toluene oxidation removal. The Ag–CeO2/TiO2 photocatalyst with porous microstructure and dispersed surface Ag particles can change the discharge mode, facilitating the interaction of plasma and photocatalysts in the PPS. We further disclose that the Ag/oxide interface can create highly active sites for surface oxidation reactions and enhances the separation of photoinduced electron-holes under the action of plasma. The intimate interaction between plasma and Ag–CeO2/TiO2 photocatalyst and enhanced surface/photocatalytic oxidation reactions on Ag/oxide interface result in the promoted performance of toluene oxidation. The creation of highly active metal/oxide interface on porous TiO2 photocatalyst may provide a strategy for the construction of high-efficiency PPS for VOCs removal.

New efficient depollution techniques for water decontamination, purification and disinfection are being sought to replace those classic methods (chemical, filtration, ozonisation, photochemical reactions) that have deficiency for some substances. The use of plasma technologies, discharges in, or in contact with, wastewater are promising approaches for the decomposition of pollutants by highly oxidative radicals, charged particles, UV radiation, etc. produced by plasma. In the present study we report on the potential of radiofrequency single and multiple filamentary Dielectric Barrier Discharge (DBD) jets for the decolorization of methylene blue (MB) dye in water solutions. Optical emission spectroscopy (OES) investigations were performed for the characterization of plasma evolving in air, and in liquid. The decolorization process was monitored by absorption spectroscopy. We determined the decolorization time, according to a variety of external parameters. The key parameters for obtaining the maximum decolorization rate were identified as being the discharge tube diameter, tube nature (glass/ceramic), the injected power in the discharge, the type of reactive gas and the number of filamentary plasma jets.