The application of gas discharge plasmas has assumed an important place in many manufacturing processes. Plasma methods contribute significantly to the economic prosperity of industrialized societies. However, plasma is mainly an enabling method and therefore its role remains often hidden. Hence the success of plasma technologies is described for different examples and commercial areas. From these examples and emerging applications, the potential of plasma technologies is discussed. Economic trends are anticipated together with research needs. The community of plasma scientists strongly believes that more exciting advances will continue to foster innovations and discoveries in the first decades of the 21st century, if research and education will be properly funded and sustained by public bodies and industrial investors.

The future for plasma science and technology

The application of dielectric barrier discharge non-thermal plasma in VOCs abatement: A review

Abstract The widespread applications of ozone technologies are established on the basis of large-scale manufacture of ozone generator and chemical reactivity of ozone. It is hence necessary to summarize the principles of ozone generation and to analyze the physicochemical properties of ozone, which are of fundamental significance to indicate its technical developments and practical applications. This review presents a summary concerning ozone generation mechanisms, the physicochemical properties of ozone, as well as the applications of ozone in water treatment. Ozone can be produced by phosphorus contact, silent discharge, photochemical reactions, and electrochemical reactions, principally proceeding by the reaction of oxygen atom with oxygen molecule. There are side reactions to the generation of ozone, however, which are responsible for ozone depletion including thermal decomposition and quenching reactions by reactive species. The solubility of ozone in water is much higher than that of oxygen, suggesting that it may be reliably applied in water and wastewater treatment. Based on the resonance structures of ozone, one oxygen atom in ozone molecule is electron-deficient displaying electrophilic property, whereas one oxygen atom is electron-rich holding nucleophilic property. The superior chemical reactivity of ozone can also be indirectly revealed by radical-mediated reactions initiated from homogenous and heterogeneous catalytic decomposition of ozone. Owing to the reliable generation of ozone and its robust reactive properties, it is worthy to thoroughly elaborate the applications of ozone reaction in drinking water disinfection and pre- or post-treatment of industrial wastewater including cyanide wastewater, coking wastewater, dyeing wastewater, and municipal wastewater. The structural characteristics of ozone reactors and energy requirement of applied technologies are evaluated. In addition, future directions concerning the development of ozone generation, ozone reactivity, and industrial wastewater ozonation have been proposed.

Ozonation in water treatment: the generation, basic properties of ozone and its practical application

Ozone is activated oxygen and it is referred to as a triatomic form of oxygen. It is a natural agent and has a broad antimicrobial property, which together with an oxidation potential, make it an attractive option for the food industry. This article focuses on the use of ozone for preservation of vegetables, fruits and fruit juices, and highlights the inactivation mechanism of microorganisms. The application of ozone in grain storage and the quality of ozone treated grains is discussed, along with the reaction kinetics of ozone in grains.

Application and Kinetics of Ozone in Food Preservation

The simultaneous removal of NOx and SO2 was demonstrated by an integrated O3 oxidation/wet atomizing system. The dielectric barrier discharge with silicone rubber dielectrics was used for generating O3 to oxidize NO and SO2. The O3 yield and O3 energy yield were evaluated to be 13.3 g/h and 53.7 g/kWh, respectively. NO was effectively oxidized by O3, while SO2 was not significantly oxidized because the reaction rate of NO oxidation was much higher than that of SO2. The highest oxidation efficiencies of NO and SO2 were 97 and 8%, respectively. NOx and SO2 were absorbed as aqueous ions with a mist of H2O2 solution supplied by an ultrasonic humidifier. The total removal efficiencies of NOx and SO2 were 88.8 and 100%, respectively. NO and SO2 were oxidized to NO2, HNO3, N2O5, and SO3 by O3. These species were absorbed to form NO3–, HSO3–, and SO42– by reactions with the H2O2 solution.

Simultaneous Oxidation and Absorption of NOx and SO2 in an Integrated O3 Oxidation/Wet Atomizing System

Experimental and theoretical study of ozone generation in pulsed positive dielectric barrier discharge

A detailed reaction kinetic model consisting of 10 species and 63 reactions is developed to investigate the energy conversion and temperature dependence in an ozone generator using oxygen pulsed discharge. The energy conversion ratios of total electric energy converted into reaction heat, heat carried by gas and heat loss to ambient, namely ηreaction, ηgas and ηloss, are obtained for the first time. The ratio of reaction heat ηreaction decreases substantially with increasing specific energy and inlet gas temperature, which represents how much energy is utilized effectively to synthesize ozone. Correspondingly, ηloss and ηgas increase gradually. ηreaction declines from 55.4% to 27.7% at inlet gas temperature of 298 K when specific energy changes from 0.06 J/cm3 to 0.78 J/cm3. The detailed reaction pathway including the degree of transformation among species for ozone formation is also obtained via kinetics simulation. Meanwhile, sensitivity analysis and rate-of-production analysis for the four most...

Energy Conversion and Temperature Dependence in Ozone Generator Using Pulsed Discharge in Oxygen

This paper studies the influence of inert gases He, Ar, Kr and Xe on ozone generation in a dielectric barrier reactor fed by oxygen feed gas. Results show that inert gas additions would lead to lower applied voltage, discharge power and reduced field. The electron energy distribution function shifts to the right though inert gas addition would lead to a lower reduced field with He, Ar and Kr addition, but it shifts to the left with Xe addition. The effective electron density decreases with inert gas content. With respect to Ar/O2, Kr/O2 and Xe/O2 mixture, conversion ratio of oxygen into ozone and ozone yield would increase with increasing Ar, Kr or Xe content, the growth rates follow the order of Xe > Kr > Ar. Such behaviors can be ascribed to the fact that Ar*, Kr* and Xe* could provide another effective pathway to produce oxygen atom through penning dissociation of O2 and metastable species due to their relatively low excitation threshold and considerable rate coefficients.

An analysis of the effect of inert gases on ozone generation using dielectric barrier discharge in oxygen

In this study, a traditional tubular reactor and an amplitude-modulated AC power supply are employed to develop a unique practical ozone generator with a widely adjustable ozone concentration and s...

Ozone Production in Coaxial DBD Using an Amplitude-Modulated AC Power Supply in Air

This experiment studies the effect of inert gases He, Ar, Kr and Xe on ozone generation within a dielectric barrier discharge reactor fed by dry air. The results show that increasing inert gas content leads to a lower applied voltage, discharge power and reduced field. Although the addition of inert gas would lead to a lower reduced field, however, the electron energy distribution function still shifts to the right. The electron density increases slightly at first and then decreases steadily with increasing Xe content, but it decreases monotonically with increasing content of He, Ar and Kr. With regard to dry air/Kr and air/Xe mixtures, ozone concentration and ozone yield show a slight initial increase, followed by a steady decrease for and , which are favorable for ozone production through the Penning dissociation of O2 due to their lower excitation energy.

Linsheng Wei

Papers

Experimental and theoretical study of ozone generation in pulsed positive dielectric barrier discharge

Energy Conversion and Temperature Dependence in Ozone Generator Using Pulsed Discharge in Oxygen

An analysis of the effect of inert gases on ozone generation using dielectric barrier discharge in oxygen

Ozone Production in Coaxial DBD Using an Amplitude-Modulated AC Power Supply in Air

The Effect of Inert Gases on Ozone Generation Using Dielectric Barrier Discharge in Dry Air