Core–shell structured Fe3O4 nanoparticles functionalized with rhodamine derived probe for the detection, adsorption and removal of Hg(II): A sensing system with ‘warning’ signal

In the present paper, core–shell structured Fe3O4 nanoparticles functionalized with rhodamine derived probe were prepared for the detection, adsorption and removal of Hg(II). The core was composed of superparamagnetic Fe3O4 nanoparticles, while the shell consisted of silica molecular sieve MCM-41 and was functionalized by rhodamine derived probe. The nanocomposite was characterized by electron microscopy images, XRD patterns, thermogravimetric analysis and N2 adsorption/desorption isotherms, which confirmed its core–shell structure. Its sensing performance towards Hg(II) was then discussed in detail. Experimental result suggested that the emission of the nanocomposite increased with the increasing Hg(II) concentration, showing emission “Off-On” effect. High sensitivity and good selectivity were observed from the nanocomposite. Owing to the highly ordered tunnels and the large surface-area-to-volume ratio of MCM-41, the nanocomposite showed fast response towards Hg(II). Whatʹs more, it was recyclable for practical application.