Cu/TiO adsorbents modified by air plasma for adsorption-oxidation of HS.

In this study, non-thermal plasma (NTP) was employed to modify the Cu/TiO adsorbent to efficiently purify HS in low-temperature and micro-oxygen environments. The effects of Cu loading amounts and atmospheres of NTP treatment on the adsorption-oxidation performance of the adsorbents were investigated. The NTP modification successfully boosted the HS removal capacity to varying degrees, and the optimized adsorbent treated by air plasma (Cu/TiO-Air) attained the best HS breakthrough capacity of 113.29 mg HS/g, which was almost 5 times higher than that of the adsorbent without NTP modification. Further studies demonstrated that the superior performance of Cu/TiO-Air was attributed to increased mesoporous volume, more exposure of active sites (CuO) and functional groups (amino groups and hydroxyl groups), enhanced Ti-O-Cu interaction, and the favorable ratio of active oxygen species. Additionally, the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results indicated the main reason for the deactivation was the consumption of the active components (CuO) and the agglomeration of reaction products (CuS and SO) occupying the active sites on the surface and the inner pores of the adsorbents.