Non-Thermal Plasma Coupled with Catalyst for the Degradation of Water Pollutants: A Review

Abstract

Non-thermal plasma is one of the most promising technologies used for the degradation of hazardous pollutants in wastewater. Recent studies evidenced that various operating parameters influence the yield of the Non-Thermal Plasma (NTP)-based processes. In particular, the presence of a catalyst, suitably placed in the NTP reactor, induces a significant increase in process performance with respect to NTP alone. For this purpose, several researchers have studied the ability of NTP coupled to catalysts for the removal of different kind of pollutants in aqueous solution. It is clear that it is still complicated to define an optimal condition that can be suitable for all types of contaminants as well as for the various types of catalysts used in this context. However, it was highlighted that the operational parameters play a fundamental role. However, it is often difficult to understand the effect that plasma can induce on the catalyst and on the production of the oxidizing species most responsible for the degradation of contaminants. For this reason, the aim of this review is to summarize catalytic formulations coupled with non-thermal plasma technology for water pollutants removal. In particular, the reactor configuration to be adopted when NTP was coupled with a catalyst was presented, as well as the position of the catalyst in the reactor and the role of the main oxidizing species. Furthermore, in this review, a comparison in terms of degradation and mineralization efficiency was made for the different cases studied.

Recent Progress and Prospects in Catalytic Water Treatment

“…The DBD configuration allows a suitable positioning of the catalyst very close to the discharge zone. 300 In this way, the interaction between the electric field and the catalyst surface is enhanced, and the interaction between the UV rays generated by the plasma and its oxidizing species with those generated by the catalyst generates a synergy. However, such a configuration is less suitable for a powder catalyst but is proper for a structured catalyst.…”

Recent Advances in Endocrine Disrupting Compounds Degradation through Metal Oxide-Based Nanomaterials

“…There are different types of reactor configurations, the most used being the dielectric barrier discharge. Solid (photo)catalysts can be the introduced in various forms, as foam, honeycomb monolith, coating on the reactor walls or electrodes, or as a packed bed [55]. Different metal oxide semiconductors have been integrated in non-plasma systems, improving the degradation efficiency of emerging contaminants and thus making the process more economically sustainable [56].…”

Cold atmospheric plasma technology for removal of organic micropollutants from wastewater—a review

“…They showed that cold plasma can effectively degrade range of phenolic compounds. Another investigation on the combined effect of heterogeneous catalysts and cold plasmas for the removal and mineralization of organic pollutants from water is summarized in the critical review of Russo et al [92]. They concluded that catalysts played a significant role to enhance the performance of the plasma systems.…”