Synthesis and surface functional group modifications of ordered mesoporous carbons for resorcinol removal

• Ordered mesoporous carbons (OMCs) were synthesized by in situ polymerization.
• OMC prepared from the 90 °C template has the largest pore size of 10.5 nm.
• The ordered structure was retained after surface modification using nitric acid.
• Surface oxygen contents increased from 13% to 28% after modification.
• Modified OMC has an adsorption capacity of 39.2 mg/g for resorcinol removal.

Ordered mesoporous carbons (OMCs) possess regular and tunable pore size, as well as stable frameworks with pore surfaces easy for modification or functionalization. These features meet the requirements of an excellent adsorbent. OMCs’ preparation involves the synthesis of an ordered silica template, introduction of carbon precursors into the silica template, carbonization of the carbon and silica composite, and finally, removal of the silica template. The pore size and functional groups on the surface are critical for an adsorption processes. In this study, OMCs were synthesized under four different temperatures (70, 90, 110, and 150 °C) to optimize the pore size. X-ray diffraction (XRD) measurement demonstrated that OMC prepared at 90 °C has the highest intensity with the largest pore size of 10.5 nm. OMC was modified with concentrated nitric acid to improve the adsorption capacity. Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the carboxyl functional groups were introduced onto the surface of the OMCs, which contribute to the increase of the adsorption capacity. XRD patterns and transmission electron microscopy (TEM) images suggest that the ordered structure is well maintained during the surface modification processes. Resorcinol, a typical total organic carbon (TOC) model compound, was selected to evaluate the adsorption behavior of the OMCs. This adsorption study showed that the modified OMC has the highest adsorption capacity of 39.2 mg/g for resorcinol removal, compared to the original OMC and the commercial Norit activated carbon. The nano-structures of the OMC and modified OMC were also characterized by scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD).

Figure optionsDownload as PowerPoint slide