Preparation of graphene-based catalysts and combined DBD reactor for VOC degradation

Abstract

The objective of this study was to compare the transformation of by-products between single dielectric barrier discharge (SDBD) and double dielectric barrier discharge (DDBD), to optimize the preparation of graphene-based catalysts and apply them in combination with DBD for VOCs degradation. The effect of three experimental conditions (initial concentration, output voltage, ow rate) on degradation rate, byproduct transformation, and mineralization was investigated comparatively for SDBD and DDBD. Graphene oxide was prepared using the improved Hummers' method, and the optimal pathway of adding KMnO 4 was selected. Graphene-based catalysts were synthesized using the ion-assisted hydrothermal method. The effect of the amount of 1-butyl-3-methylimidazolium hexa uorophosphate ([BMIM]PF6) on the preparation of three typical transition metal catalysts (Mn, Fe, and Ti) was studied. It was found that NO 2 transformation rate of DDBD was higher than that of SDBD. The addition amount and interval time of KMnO 4 affect the preparation of graphene oxide. [BMIM]PF6 dose of 0.25 ml, the preparation of three catalysts showed the best performance. MnO x /rGO exhibited superior performance in the degradation of benzene series, NO transformation, NO 2 transformation, CO 2 selectivity, and energy e ciency. FeO x /rGO exhibited superior performance for O 3 transformation. Mn 3 O 4 and Fe 3 O 4 played a leading role in promoting the degradation of the benzene series and the transformation of by-products. IntroductionVolatile organic compounds (VOCs) include non-methane hydrocarbons, oxygenated volatile organic compounds, and organochlorine compounds (Park et al., 2013). The emissions of these substances to natural environments harm human health and the ecological environment (Ehn et al., 2014). In most parts of China, the emissions of VOCs are dominated by aromatic hydrocarbons, which are high in concentration and di cult to be removed (