Removal of ethyl mercaptan over Fe and Ce doped hexaniobate nanotubes

In this study, removal characteristics of ethyl mercaptan (C2H5SH) on hexaniobate nanotubes (HNT) and the metal-doped hexaniobate nanotubes (M-HNT) fabricated by ion exchange-flocculation-calcination process were investigated in a fixed-bed reactor. The detailed characterizations of the as-prepared catalysts were characterized by XRD, SEM, TEM, BET, Raman and XPS technologies. The results show that the removal capacity of ethyl mercaptan over hexaniobate nanotubes is markedly improved through doping of Fe and Ce. The order of breakthrough adsorption capacity for ethyl mercaptan of different catalysts is as follows: Fe/Ce-HNT (47.73 mg g(-1)) > Fe-HNT (43.69 mg g(-1)) > Ce-HNT (39.94 mg g(-1)) > HNT-450 (11.23 mg g(-1)) > HNT (6.24 mg g(-1)). Moreover, the oxidation activity can be enhanced by the co-doping of Fe and Ce. The XPS results indicated that the adsorbed ethyl mercaptan on the surface of Fe/Ce-HNT is oxidized to corresponding metal sulfonates, sulfites and sulfates. In addition, 89.5% of the breakthrough adsorption capacity is maintained after four regenerations. Finally, a potential mechanism for ethyl mercaptan removal over the Fe/Ce-HNT catalyst was proposed.