Combining non-thermal plasma with heterogeneous catalysis in waste gas treatment: A review

Abstract

Plasma driven catalysis is a promising technology for waste gas treatment characterized by higher energy efficiencies, high mineralization rates and low by-product formation. The combination of heterogeneous catalysts with non-thermal plasma can be operated in two configurations: positioning the catalyst in the discharge zone (in-plasma catalysis) or downflow the discharge zone (post plasma catalysis).In a first part of the review, changes of plasma properties resulting from the introduction of catalyst material are discussed. It has been reported that discharge types can even change. Accordingly, it was reported that microdischarges are formed within the catalyst pores. Changing plasma characteristics can eventually result in enhanced production of new active species, increasing the oxidizing power of the plasma discharge.In a second part, it is discussed that plasma discharges also affect catalyst properties such as a change in chemical composition, enhancement in surface area or change of catalytic structure. These phenomena partially explain why catalyst adsorption kinetics of airborne pollutants are affected when exposed to plasma discharges.It is also reviewed that the synergy of combining plasma with catalysts can not only be attributed to the production of new reactive species. Also plasma photon emission or thermal hot-spots can initiate catalytic pollutant oxidation reactions.To conclude, an overview of recently published manuscripts concerning plasma catalysis for volatile organic compounds abatement is given. It is also discussed why heterogeneous plasma catalysis has high potential for the simultaneous abatement of NO x and hydrocarbons. #

Mode Transition of Filaments in Packed-Bed Dielectric Barrier Discharges

“…Plasma catalysis is gaining increasing interest for various environmental applications, such as gaseous pollutant removal, the splitting of CO 2 , hydrogen generation and O 3 production [1][2][3][4][5][6][7][8][9]. Plasma catalysis can be regarded as the combination of a plasma with a catalyst, and often results in improved performance, in terms of selectivity and energy efficiency of the process.…”

Fluid model for a partially packed dielectric barrier discharge plasma reactor

“…Packed bed dielectric barrier discharge (DBD) is being increasingly used as a chemical reactor for remediation of environmental pollutants (e.g., NOx, SOx, and VOCs), and conversion of greenhouse gases to useful chemicals. [1][2][3] The non-equilibrium nature of DBD provides major advantage, by allowing operation at atmospheric pressure and ambient conditions. This helps to overcome the thermodynamic barriers in chemical reactions and provides high reactivity at room temperatures.…”

“…4,5 In cases, when the packing material is a catalyst, the so called "plasma-catalysis" provides a synergistic effect and also helps to improve the selectivity towards desirable products. 2,6 Additional features such as easy operation, moderate capital cost, and simple scalability have led to extensive research on packed bed DBDs. 7 Several studies which have used packing material in conjunction with plasma in a DBD have found enhanced performance in comparison to a plasma alone system; 2,3,6,[8][9][10][11][12] however, many studies have also reported a negative impact on the performance.…”

“…2,6 Additional features such as easy operation, moderate capital cost, and simple scalability have led to extensive research on packed bed DBDs. 7 Several studies which have used packing material in conjunction with plasma in a DBD have found enhanced performance in comparison to a plasma alone system; 2,3,6,[8][9][10][11][12] however, many studies have also reported a negative impact on the performance. 9,[13][14][15] This unfavorable response has been shown to be related to packing configuration and the void fraction of the discharge in the packed bed DBD.…”

Biological technologies for the removal of sulfur containing compounds from waste streams: bioreactors and microbial characteristics

“…Bioreactors integrated with non-thermal plasma Nonthermal plasma (NTP) is a promising technology for waste gas treatment (Durme et al 2008). Previous research using a non-thermal dielectric barrier discharge plasma reactor filled with ceramic Raschig rings exhibited good hydrogen sulfide removal performance (Liang et al 2011).…”