Surface modification of high Cu-loaded activated carbon fiber adsorbent by air plasma.

The ACF adsorbent with high Cu loading was treated with dielectric barrier discharge plasma to mitigate the negative effects of high Cu loading and enhance PH and HS adsorption and oxidation. Bruno-Emmett-Taylor (BET) result showed that the specific surface area of the adsorbent after air plasma modification was almost three times that before modification. X-ray photoelectron spectroscopy (XPS) findings revealed that the amino group was added to the adsorbent's surface, increasing lattice oxygen and chemisorbed oxygen. The adsorbent's large specific surface area, excellent surface active oxygen, and abundance of basic groups facilitate PH and HS adsorption and oxidation. The scanning electron microscopy showed that air plasma modification exposed more active components and uniformly dispersed them on the surface of adsorbent, thereby improving the adsorption performance. Activity evaluation results showed that the adsorbent has the best ability to capture PH and HS after being modified by air plasma at 4 kV voltage for 10 min. The adsorbent's breakthrough ability at high space velocity (WHSV: 60,000 h) is 190 mg P/g and 146 mg S/g, respectively, which is 74 % and 60 % greater than that before modification. This is a great improvement over previous studies. In addition, the possible mechanism of adsorbent deactivation was proposed.