Preparation of Macroporous Double-Network MoS₂-Based Beads for Efficient and Selective Removal of Hg(II) from Water

Abstract

Molybdenum disulfide (MoS 2 ) nanosheets have exhibited remarkable performance in mercury (Hg(II)) immobilization from complex aqueous environments, whereas the issues of aggregation and separation inhibit their application in real-world scenarios. Herein, a facile and general structuring method via polymer cross-linking was presented to construct recyclable double-network MoS 2 -based beads (DMBs) for efficient and selective Hg(II) removal from various water matrices. The porous structure and strong hydrogen-bonding interactions between the polymer and MoS 2 enhanced the reactivity and stability of DMBs for Hg(II) capture. The as-synthesized DMBs exhibited high Hg(II) adsorption capacity (253.6 mg g −1 at 25 °C), rapid kinetics, wide working pH range (2−9), great Hg(II) selectivity (K d = 8.53 × 10 6 mL g −1 ), and anti-interfering ability. The mechanism of Hg(II) capture by DMBs, mainly the surface coordination (Hg−S) and formation of Hg(II) complexes (-S-HgOHgCl, -S-HgCl, and -S-HgOHgOH), was proposed in combination with characterizations and theoretical calculations. Moreover, the continuous-flow adsorption performance (∼14.5 L of Hg(II)-containing wastewater per gram of adsorbent treated) and reusability (>90% of Hg(II) removal efficiency after 12 cycles) of the DMBs validated their practical applicability. Overall, this study suggests a promising approach for engineering advanced nanomaterials to facilitate their implementations in water purification facilities.