Functionalized SiO₂ With S-Donor Thiophene: Synthesis, Characterization, and Its Heavy Metals Adsorption

Abstract

Porous silica has been chemically modified with thiophene using the heterogeneous route. This synthetic route involved the reaction of native silica, SiO₂, with a commercial silylating agent, 3-glycidoxypropyltrimethoxysilane, followed by the immobilization of the thiophene chelating groups on the support. The resulting material has been characterized by thermogravimetry, FTIR spectra, and elemental analysis. The solid was also studied and evaluated by determination of the surface area using the BET equation, and the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. pore sizes. The new synthesized material was employed in a batch method as adsorbent from aqueous solutions of Hg²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Zn²⁺, K⁺, Na⁺, and Li⁺.

Keywords:

• Adsorption
• chemical synthesis
• metals
• S-donor thiophene
• silica

Notes

^a So: native silica.

^b Solid–liquid extraction of individual cations using MSiTh.

^c Solid–liquid extraction in competitive mode using MSiTh.

^d K_d: The distribution ratio of the metal ion in competitive adsorption (mL/g).

^e K_i: A selectivity coefficient for the binding of Hg²⁺ in competitive adsorption.