Active Mercury(II) Ion Removal: Stoichiometrically Controlled Thiol-Functionalized Mesoporous Silica by a Mass Production Spray Dry System

Stoichiometrically controlled thiol-functionalized mesoporous silica particles are synthesized by a spray dry technique in one step. The EDS (energy dispersive X-ray spectrometer) mapping shows that thiol groups are well dispersed throughout the particles without phase separation at micrometer scale. From TEM (transmission electron microscope) observation, SAXS (small-angle X-ray scattering) measurements, and N2 adsorption–desorption isotherms, it is proven that the thiol groups can be successfully embedded in the frameworks up to 30% without any collapse of ordered mesoporous structures. The amount of the embedded thiol groups in the final products can be stoichiometrically controlled by changing the compositions of the initial precursor solutions, as is confirmed by 29Si NMR measurements. The total adsorption capacity of mercury(II) ions was increased in proportion to the amount of the thiol groups embedded in the frameworks.