Morphology and surface hydroxyl engineering of H4Nb6O17 nanotubes for enhanced ethyl mercaptan removal

Abstract

Ethyl mercaptan is usually present in natural gas and biogas, and must be removed due to its toxic, malodorous and corrosive properties. The characteristics content of surface functional groups plays a vital role for the adsorption performance of the adsorbent. In present study, a facile method was proposed to adjust the morphology and structure, as well as the amount of the surface hydroxyl groups of H4Nb6O17 nanotubes. The synthesis of H4Nb6O17 nanotubes with different morphology and structure can adjust the content of surface hydroxyl groups by controlling the flocculation process of [Nb6O17]4- nanosheet sol. By reducing the flocculation rate, more nanosheets are curled to form regular nanotubes, thereby increasing the surface hydroxyl groups of the nanotubes and improving the adsorption capacity of ethyl mercaptan. The dynamic adsorption experiments show that the obtained H4Nb6O17 nanotubes present high ethyl mercaptan adsorption capacity and great cyclic regeneration performance. The high sulfur capacity of H4Nb6O17 nanotubes can be well explained by the abundant surface hydroxyl groups, large specific surface area and hierarchical pore structure. This work provided new insights into design and preparation of high-efficiency adsorbents by morphology and structure engineering.