Cu/ACF adsorbent modified by non-thermal plasma for simultaneous adsorption-oxidation of H₂S and PH₃

Non-thermal plasma (NTP) surface modification technology is a new method to control the surface properties of materials, which has been widely used in the field of environmental protection because of its short action time, simple process and no pollution. In this study, Cu/ACF (activated carbon fiber loaded with copper) adsorbent was modified with NTP to remove H₂S and PH₃ simultaneously under low temperature and micro-oxygen condition. Meanwhile, the effects of different modified atmosphere (air, N₂ and NH₃), specific energy input (0-13 J/mL) and modification time (0-30 min) on the removal of H₂S and PH₃ were investigated. Performance test results indicated that under the same reaction conditions, the adsorbent modified by NH₃ plasma with 5 J/mL for 10 min had the best removal effect on H₂S and PH₃. CO₂ temperature-programmed desorption and X-ray photoelectron spectroscopy (XPS) analyzes showed that NH₃ plasma modification could introduce amino functional groups on the surface of the adsorbent, and increase the types and number of alkaline sites on the surface. Brunauer-Emmett-Teller and scanning electron microscopy showed that NH₃ plasma modification did not significantly change the pore size structure of the adsorbent, but more active components were evenly exposed to the surface, thus improving the adsorption performance. In addition, X-ray diffraction and XPS analysis indicated that the consumption of active components (Cu and Cu₂O) and the accumulation of sulfate and phosphate on the surface and inner pores of the adsorbent are the main reasons for the deactivation of the adsorbent.