Acid catalyzed synthesis of ordered bifunctionalized mesoporous organosilicas with large pore

Thiol-functionalized mesoporous ethane-silicas with large pore were synthesized by co-condensation of 1,2-bis(trimethoxysily)ethane (BTME) with 3-mercaptopropyltrimethoxysilane (MPTMS) using nonionic oligomeric polymer C18H37(OCH2CH2)10OH (Brij-76) or poly(alkylene oxide) block copolymer (P123) as surfactant in acidic medium. The results of powder X-ray diffraction (XRD), nitrogen gas adsorption, and transmission electron microscopy (TEM) show that the resultant materials have well-ordered hexagonal mesoscopic structure with uniform pore size distributions. 29Si MAS NMR, 13C CP-MAS NMR, FT-IR, and UV Raman spectroscopies confirm the attachment of thiol functionalities in the mesoporous ethane-silicas. The maximum content of the attached thiol group (-SH) in the mesoporous framework is 2.48 mmol/g. The ordered mesoporous materials are efficient Hg2+ adsorbents with almost every -SH site accessible to Hg2+. In the presence of various kinds of heavy metal ions such as Hg2+, Cd2+, Zn2+, Cu2+, and Cr3+, the materials synthesized using poly(alkylene oxide) block copolymer (Pluronic 123) as surfactant show almost similar affinity to Hg2+, Cd2+, and Cr3+, while the materials synthesized using oligomeric polymer C18H37(OCH2CH2)10OH (Brij-76) as surfactant exhibit high selectivity to Hg2+.