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Abstract: Sulfo-group functionalized microporous and mesoporous silica based-on a MCM-41 framework which showed solid acid property were synthesized and characterized by adsorption microcalorimetry. Both the sulfo-functionalized microporous and mesoporous silica (Micro-SO3H and Meso-SO3H) were prepared by the oxidation of thiol group (–SH) included mesoporous silica which was obtained through the hydrolysis and co-condensation of tetramethoxysilane (TMOS) and mercaptopropyl trimethoxysilane (MPTMS). The samples have an ordered two-dimensional hexagonal pore array similar to that of MCM-41 as depicted from the XRD patterns. Nitrogen adsorption also shows that both microporous and mesoporous silica have pore characteristics similar to MCM-41, i.e. high surface area and high pore volume. However, pore regularity, surface area and pore volume decreased as the MPTMS loading increased. Solid-state 29Si NMR indicated that the sulfo groups were successfully incorporated into both microporous and mesoporous silica frameworks. This sulfo-functionalized porous silica have high NH3 uptakes and high differential heats of NH3 adsorption, suggesting the presence of strong acidic sulfo groups on the silica surface. Acid catalyses of the samples were characterized by the isomerization reaction of but-1-ene to cis, trans-but-2-ene. [Copyright &y& Elsevier]

The limitations of the present hemodialysis have led towards the development of several wearable artificial kidney prototypes. The most important component of the miniaturized model, as compared to the hemodialysis, is the closed-system dialysate. Typically, these models utilize activated carbon as adsorbents. With superior adsorbents as replacements, the amount of dialysate required to remove uremic toxins could be reduced and regenerated. Mesoporous silica could perform better than generic activated carbon since the silica surface could be functionalized for target specific adsorption. This paper evaluates the performance of mesoporous silica SBA-15 and amine-functionalized SBA-15 for the removal of major uremic toxin constituent urea. Results are promising as mesoporous silica could potentially replace activated carbon in artificial kidney applications due to the larger urea adsorption capacity and improved adsorption kinetics. Functionalization of mesoporous silica further improved its urea adsorption capacity. Though activated carbon has theoretically higher surface area, its low affinity towards urea remains a drawback. [ABSTRACT FROM AUTHOR]