Synthesis and characterization of sulfur-functionalized silica materials towards developing adsorbents for mercury removal from aqueous solutions

• Spherical sulfur-functionalized adsorbents were successfully synthesized.
• Low porosity characteristics were observed for sulfur-functionalized adsorbents.
• Sulfur-functionalized adsorbents show higher Hg(II) adsorption than MCM-TEOS.
• Functionalization via co-condensation method resulted in higher Hg(II) adsorption.

Three methods were used to synthesize sulfur-functionalized silica materials with spherical morphology: (a) impregnation of CS2 and S8 onto preformed silica support (MCM-TEOS); (b) co-condensation of TEOS and BTESPT/MPTMS; and (c) direct use of BTESPT and MPTMS as precursors. The presence of sulfur functional groups in the synthesized adsorbents was confirmed by the FTIR and EDX analyses. Lower pore arrangements and pore characteristics of sulfur-functionalized silicas were found which were observed from the XRD and nitrogen adsorption desorption analysis. However, these samples showed higher adsorption capacity than silica without sulfur. The highest Hg(II) adsorption capacity (47.50 mg/g) was obtained by the MPTMS-SMs(I) adsorbent synthesized through the co-condensation method.

Figure optionsDownload as PowerPoint slide