Highly dispersed transition metal oxide-supported activated carbon prepared by plasma for removal of elemental mercury

Abstract

Recently, transition metal oxide-supported activated carbon (MOx/AC) has been extensively investigated for Hg0 removal, due to its high Hg0 adsorption capacity and reproducibility. Non-thermal plasma (NTP) was applied for the preparation of transition metal oxide-supported AC in this work. The obtained adsorbents were investigated for the removal of Hg0. The adsorbents were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), temperature-programmed reduction of H2 (H2-TPR), and so on. The results indicated that the plasma treatment process instead of heat treatment could effectively promote the dispersion of active site and catalytic oxidation property of adsorbent. Consequently, the CeO2/AC-P and Co3O4/AC-P adsorbents prepared by plasma treatment exhibited higher Hg0 removal efficiency than the CeO2/AC and Co3O4/AC adsorbents prepared by conventional heat treatment. The Hg0 removal efficiency of the adsorbent could be recovered by the temperature-programmed desorption (TPD) process at a relatively mild regeneration temperature, while retaining high stability even at higher temperatures. The present work showed that plasma treatment could serve as an efficient method of preparing catalyst.