Universal pathway towards metal sulfides decorated 3D porous Ti3C2Tx MXene aerogel for vapor-phase mercury removal

Abstract

Utilization of monolithic mineral sulfide-based sorbent for the fix-bed elemental mercury (Hg0) removal is regarded as a predominant predicament in the field of Hg0 abatement. In this work, a general and facile route was exploited to establish CuS particles decorated 3D porous Ti3C2Tx MXene aerogel via divalent Cu2+ cations induced assembly combined with subsequent high-temperature sulfurization treatment, during which, uniform CuS particles were homogeneously anchored throughout the Ti3C2Tx substrate. The obtained 3D CuS/Ti3C2Tx MXene aerogel exhibited satisfactory textural property, hierarchical pore structure and strong interaction between Ti3C2Tx MXene and CuS. Meanwhile, the inherent restacking of Ti3C2Tx MXene nanosheet and serious agglomeration of CuS can also be effectively avoided in the formation of aerogel. Those structural advantages originating from this novel gelation process favorably contributes to satisfactory Hg0 mass transfer and sufficient utilization of CuS active ligands, which largely strengthens Hg0 removal performance and broadens the fix-bed application of mineral sulfides. Consequently, the Hg0 capture capacity and adsorption rate of CuS/Ti3C2Tx MXene aerogel reached 90596.4 g m−3 and 120.64 g m−3 min−1, respectively, far outbalancing those of the reported in-situ selenized copper foam with excellent Hg0 removal activity. The impressive Hg0 sequestration performance is attributed to its relatively large specific surface area, layered pore channel, and highly dispersed CuS particles, largely boosting Hg0 mass transfer and following sequestration. Moreover, other mineral sulfides/Ti3C2Tx MXene aerogels can also be constructed by just replacing divalent metal cations, which makes the initial effort towards the fix-bed utilization of mineral sulfides-based aerogel for vapor-phase Hg0 immobilization.