Preparation of monodispersed mesoporous silica particles and their applications in adsorption of Au3+ and Hg2+ after mercapto-functionalized treatment

• Mesoporous silica particles were first synthesized by using THEEDA as catalyst.
• The particles with the size about 30 nm present stable colloidal suspensions.
• Thiol functional groups were modified into the silica particles.
• Examined the influence of adjusting TEOS/MPTMS on the structure and morphology.
• The modification particles could effectively remove heavy metal ions Au3+ and Hg2+.

Colloidal suspensions of monodispersed nanoporous silica particles were first successfully synthesized by using small organic amine (N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine) as basic catalyst; and then, the mercaptopropyl functionalized counterpart was also fabricated by co-condensation of mercaptopropyl silane and tetraethyl orthosilicate in a similar way. These nanoporous silica particles were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), nitrogen adsorption-desorption and X-ray diffraction. Experimental results indicated that all the spherical nanoporus silica particles are uniform (with the size of about 30–40 nm) and possessed large specific surface area (about 500 m2/g), large pore volume (>1.6 cm3g−1) and narrow pore sizes distribution (<3 nm). Furthermore, the mercaptopropyl functionalized products served as adsorbent to efficiently remove Hg2+ and Au3+ ions in water.

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