3. Conclusions
In conclusion, the combination of electrospinning, etching, oxidation activation and hydrothermal treatments has been applied to synthesize the surface area enlarged CNFs supported Zn-Mn-based sorbents for high temperature coal gas desulfurization. SiO2 was introduced as hard template for the purpose of creating hollow carbon shells on CNFs, then enlarging the surface area of the porous carbon nanofibers and increasing the loading content of active components. As revealed in the various characterizations, the modified PCNFs that with 24 wt.% SiO2 possess a specific surface area of 250.684 m2 g-1 and a Mn2+loading content of 17.8 wt.%, which are 4.9 and 3.3 times higher than that of pristine CNFs. More important, the sulfur capacity of sorbent supported by 24PCNFs is 2.3 times higher than that with pristine CNFs. Furthermore, the existence of MnOx ‘seed layer’ also serves for the uniformly growth of nanosized ZnO and the promotion of desulfurization performance of the as-prepared sorbent. Zn@MnOx /24PCNFs sorbent prepared with 24 wt.% SiO2 and 0.01 M Zn2+ possesses an optimal breakthrough capacity (9.63 g S 100 g-1sorbent) and excellent utilization rate of active components (overall 73%) with a high utilization rate of ZnO reaches up to 117%. Methods like TEM and SEM suggest that the contributions come from the synergetic effects of the enlarged surface area of porous carbon nanofibers and the oxidation of KMnO4 that providing the potentials for rapid mass transfer and chemical reaction. In brief, the PCNFs supported Zn-Mn bimetallic desulfurization sorbent can facilitate the H2S clean-up in electric power plant and coal chemical industry.