Urea is a robust and ubiquitous toxin produced in mammalian biological systems including humans. For individuals with kidney failure, increased levels of blood urea nitrogen cause various issues including fatigue, sleeplessness, swelling, and bloody urine, to name a few. There continues to be much research in the area of materials for direct urea adsorption. To that end, mesoporous silica was prepared under varied conditions to produce relatively monodisperse pore sizes ranging from 60 to 300 Angstroms in diameter. Adsorption of two metal cations, Cu<sup>2+</sup> and Fe<sup>2+</sup>, were investigated for increased urea adsorption. Metals were directly adsorbed or adsorbed after amino functionalization, via grafting, of the mesoporous silica. Eluent solution contained 8.9 mM urea along with dialysate buffer. The adsorption of urea was determined using UV-Vis spectroscopy on collected fractions of the effluent. Urea adsorption was observed to increase marginally with pore size and decrease marginally with the size of grafted amine. Overall results suggest that crowding within the mesoporous framework from grafted amines and adsorbed metals may have hindered the adsorption of urea from solution. The combination of the grafted amine, the metal cation, and surrounding urea molecules were enough to obstruct the mesoporous framework and barricade other urea complexes from passing through to deeper adsorption sites.

Investigation of mesoporous silica for urea adsorption

255th National Meeting (2018)

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