Self-assembly of mercury-ion recognizing CuS nanocrystals into 3D sponge-like aerogel towards superior mercury capturer with outstanding selectivity and efficiency

Abstract

This work reports fabrication of a novel 3D sponge-like CuS aerogel (CuS AG) at room temperature by self-assembly of CuS nanocrystals and its application in recognition, capture and enrichment of mercury ions. The structure of CuS AG was characterized by SEM, TEM, XRD, FTIR and N2 adsorption − desorption isotherms, and its physicochemical properties were investigated by ICP-OES, ICP-MS, XPS, EDS elemental mapping and estimation of typical thermodynamic parameters. The highly porous Cu-S network structure has a large specific surface area (159 m2 g−1), a large pore volume (0.50 cm3 g−1) as well as abundant surface Cu-S sites and ion channels. As a result, CuS AG not only exhibits superior selectivity towards Hg2+ ions among other interfering metal ions via surface substitution reaction, but also demonstrates unprecedented capture capacity (3667 mg g−1) and superfast capture kinetics (99% removal within 30 s). These unique features endow CuS AG with a wide working range of pH (2–10) and temperature (0-45 °C) as well as suitability for practical complex samples. CuS AG was used as a new type of extracting materials for convenient enrichment and separation of ultratrace Hg2+ even at ppt level, achieving an enriching factor as high as 260. The current work may open a new avenue to the design and fabrication of high performance materials for recognition, adsorption, enrichment, separation and sensing of metal ions as well as catalysis, energy storage and bioapplications.