Sepiolite-CuₓSy pellets fabricated via extrusion-spheronization for elemental mercury removal in natural gas

The inherently poor self-binding capability of copper sulfide (CuS) represents a significant obstacle to its practical application in Hg 0 removal from natural gas, as it hinders the mechanical fabrication of robust sorbent monoliths required for stable and efficient operation in fixed-bed reactor systems. In this study, Sepiolite-Cu x S y pellets with controllable sizes were synthesized through sequential room-temperature CuS impregnation on sepiolite substrates, followed by extrusion-spheronization processing. The obtained Sepiolite-Cu x S y pellets exhibited excellent Hg 0 capture efficiency at the representative temperature of natural gas processing of 30 °C. Hydrogen sulfide obviously enhances Hg 0 removal efficiency through an in situ sulfidation mechanism, demonstrating its potential for Hg 0 immobilization in natural gas. Low-field NMR analysis confirmed the increase of weakly bound water in Sepiolite-Cu x S y , which enhanced the formation of the hydration layer and significantly improved its mechanical strength and wear resistance. To sum up, a groundbreaking granulation strategy was developed in this work to prepare a superior CuS based pellet sorbent for the removal of mercury from natural gas, the elucidated mechanisms also would benefit the understanding of the role of hydration layer in material molding.