Easy, Fast, Selective, and Simultaneous Separation of Hg(II) and Oil via Loofah-Sponge-Inspired Hierarchically Porous Membranes

In this work, Cu2Se/Cu membranes (CSMs) of hierarchical pores were fabricated via chemical dissolution of Cu and Se followed by redeposition of cuprous selenide (Cu2Se) on copper membranes (CMs), and applied for adsorption/removal/separation of Hg(II) among a variety of interfering metal ions. The CSM demonstrates the best comprehensive performance among previous Hg(II) adsorption membranes, having high selectivity (KHg/M = 2.9 × 104–3.0 × 105), high efficiency (>99%, 5 s to 3 min), high adsorption capacity (505 mg/g), and high flux (2.0 × 106 L m–2 h–1). Meanwhile, effects of Hg(II) concentration, flow rate, and the number of membrane layers and adsorption cycles were also investigated on the removal of Hg(II). Moreover, a Cu2Se/Cu membrane-plasma (CSM-p) with superhydrophilicity/underwater superoleophobicity was prepared on the basis of CSM, and simultaneous removal of Hg(II) and oil was realized by using CSM and CSM-p in combination. This work not only provides a new reference for design of highly selective, efficient metal ion adsorption/enrichment/separation materials but also presents a novel approach to the removal/enrichment/separation of multiple complex contaminants by the combination of different functional membranes.