Surface-Engineered Sponge Decorated with Copper Selenide for Highly Efficient Gas-Phase Mercury Immobilization

The paramount challenge in design and synthesis of materials for vapor-phase elemental mercury (Hg⁰) immobilization is to achieve a balance between performance and economy for practical applications. Herein, a newly designed electroless plating coupled with an in situ selenization method was developed to construct a copper selenide (Cu₂Se)-functionalized commercial polyurethane sponge (PUS) as an efficient Hg⁰ trap. Intrinsic features such as easy availability of the raw material, facile preparation, and excellent performance guarantee the Cu₂Se/PUS to be applicable in industrial uses. The Cu₂Se/PUS exhibits a maximum adsorption capacity (Q_m,Cu) of 25.90 mg·g^-1, while this value is 758.80 mg·g^-1 when normalized to the Cu₂Se coating amount. This value of Q_m,Cu is equal to 79.7% of its corresponding theoretical value (Q_t,Cu), far exceeding the availability of Cu₂Se anchored on other supports. Meanwhile, the Cu₂Se/PUS exhibited a quick response for Hg⁰, with an extremely high uptake rate of 1275.84 μg·g^-1·min^-1. Even under harsh conditions, the Cu₂Se/PUS still immobilizes Hg⁰ effectively, which is crucial for real-world applications. This work not only provides a promising trap for permanent Hg⁰ sequestration from industrial sources but also illustrates a versatile platform for the economic fabrication and practical application of advanced functional sponges in diverse environmental remediation.