Synthesis of Amine/methyl Bifunctionalized SBA-15 with Hexagonal Platelet Morphology and Its Application in Bilirubin Adsorption

Amine/methyl bifunctionalized SBA-15 materials(AMS) were directly synthesized by co-condensation of 3-aminopropylmethyldiethoxysilane and tetraethoxysilane using an amphiphilic block copolymer as template under acidic-catalyzed and inorganic-salt-assisted conditions. X-ray diffraction, N-2 sorption analysis, transmission electron microscopy, Fourier transform infrared spectra and solid-state nuclear magnetic resonance were used to identify the well-ordered mesostructure and the grafting of amine and methyl groups on the surface of the synthesized materials. The addition of inorganic salt KCl was proven to play an important role in the formation of the highly ordered mesostructure. The scanning electron microscopy images showed that the morphologies of AMS samples shifted from hexagonal platelet to fiberlike morphology with increasing KCl concentration from 1.0 mol/L to 2.0 mol/L. The AMS sample with platelet morphology exhibited faster bilirubin adsorption rate and higher bilirubin adsorption capacity than AMS and pure SBA-15 samples with fiberlike morphology. This could be attributed to the fast molecular transport based on the short mesopore channels and the strong interaction between organic groups(amine and methyl) of AMS and bilirubin molecules. Futher studies using packed-bed columns filled with AMS samples in extracorporeal recirculation units are under investigation.