NiO-Modified Coconut Shell Based Activated Carbon Pretreated with KOH for the High-Efficiency Adsorption of NO at Ambient Temperature

Abstract

In this study, coconutshell-, coal-, and wood-based activated carbon were selected as the adsorbents for NO adsorption. KOH and transition metal oxides (CuO, FeOx, and NiO) were further adopted to improve the NO removal efficiency and adsorption capacity at ambient temperature. The results showed that CSAC-KOH(3)-NiO(10) adsorbents (coconut shell based activated carbon modified by 3% KOH and then 10% NiO) achieved the highest removal efficiency of NO (above 95.6%) and adsorption capacity (5.26 mg/g) within 60 min. XPS and NO-TPD results indicated that the increase of −C–O and OH–/Ox– species might be the reasons for good removal efficiency of NO over CSAC-KOH, while the increase of OH-/Ox– and lattice oxygen (O2– in Ni–O) species is the reason for the CSAC-KOH-NiO sample. The medium sites of the active adsorbed oxygen (Ox–) species and strong sites of lattice oxygen are the major adsorption sites on the surface of CSAC-KOH-NiO. The possible NO adsorption process were proposed that the main nitrite species...