Performance of Toluene Removal in a Nonthermal Plasma Catalysis System over Flake-Like HZSM-5 Zeolite with Tunable Pore Size and Evaluation of Its Byproducts

Abstract

In this study, a series of HZSM-5 catalysts were prepared by the chemical liquid-phase deposition method, and low concentration toluene degradation was carried out in an atmospheric pressure dielectric barrier discharge (DBD) reactor. The catalysts were characterized by X-ray powder diffraction (XRD), SEM, TEM, and N2 adsorption analysis techniques. In addition, several organic contaminants were used to evaluate the adsorption performance of the prepared catalysts, and the effect of pore size on the removal efficiency of toluene and byproduct formation was also investigated. The unmodified HZSM-5 zeolite (Z0) exhibited good performance in toluene removal and CO2 selectivity due to the diffusion resistance of ozone and the amounts of active species (OH• and O•). Meanwhile, the time of flight mass spectrometry (TOF-MS) result showed that there were more byproducts of the benzene ring in the gas phase under the action of small micropore size catalysts. Moreover, the surface byproducts were detected by gas chromatography–mass spectrometry (GC-MS).

Investigating the impact of catalysts on N2 rotational and vibrational temperatures in low pressure plasmas

“…PAC has recently received much attention within the plasma community because the non-thermal nature of the plasmas employed allows access to processes energetically unavailable under thermal conditions and because of the enormous potential to increase feed gas conversion [1][2][3][4]. PAC can be widely applied across a wide range of disciplines and applications, including treatment of waste gases [5,6]; CO 2 capture and conversion to highvalue materials [7,8]; methane reforming [9,10]; ammonia synthesis [11]; and fabrication of carbon nanostructures and supported nanocatalysts via non-thermal plasma methods [12,13]. Regardless of end application, the fundamental scientific questions and challenges that must be addressed before implementation of PAC as a viable technology are remarkably similar, such as optimized reactor and catalyst design.…”

Boosting VOCs elimination by coupling different techniques

“…Although plasma catalysis has been proven to be more efficient than the individual techniques for VOC abatement, the plasma discharge is continuously operating, resulting in reduced energy efficiency as most of the discharge energy will be utilized to excite the background gas (O 2 and N 2 ) [208] . Thus, for the treatment of the large volume of exhaust gas containing very low concentrations of VOCs (< 100 ppm), the alternate approach of adsorption plasma catalysis (APC), also known as cycled "storage-discharge", has been proposed and investigated [209,210] . Basically, APC involves two operating steps [Figure 14A]: (i) VOC in low concentration from exhaust or flue gas is trapped or adsorbed on the adsorbent and/or catalyst (storage stage-plasma off); and (ii) the trapped or adsorbed VOC is oxidized by NTP discharge (discharge stageplasma on) [187] .…”

Room-temperature degradation of o-xylene in simulated air using an online-regenerable plasma-catalysis reactor with low amounts of nanosized noble metals on Co3O4

“…Among them, NTP technology has been widely studied and used to control the emission of low-concentration VOCs due to its better removal ability at atmospheric pressure, simple equipment system, low heat loss, and high pollutant tolerance [9,10]. However, the oxidation process of VOCs using NTP technology generates harmful by-products [11,12]. VOC oxidation using NTP combined with catalysts can effectively reduce the generation of harmful by-products, but there are still problems, such as low energy efficiency and low CO 2 selectivity [13,14].…”