archives@tulane.edu / Converting biomass to fuel and chemicals has attracted significant attention in recent years due to rising energy demands and the need for carbon neutral feedstocks. Lignin and cellulose are typically the main chemical components of biomass and must be depolymerized to yield sugars, which can then be enzymatically converted into alcohols for fuel. However, the depolymerization process yields side products including organic acids, phenols, and other aromatics that inhibit fermentation even at dilute concentrations. Here we investigate silicas with tailored organic surface functionalities as solid-phase adsorbents for selective removal of these chemical species. Two classes of molecules, carboxylic acids and phenol derivatives, were used as model targets for capture using functionalized ordered mesoporous silica (OMS) as a support. Chapter (3) discusses acetic acid capture, where uptake was compared using primary, secondary, tertiary, and quaternary amine grafted OMS. It was found that increasing the degree of methylation on the amine increases uptake when an equimolar functional group surface density is used. However, the aminosilane packing density was found to be crucial to performance with variation depending on the ligand bulk as well as silica support properties. Solutions conditions during uptake were varied to conclude that electrostatic and hydrophobic interactions were the primary uptake mechanisms. In the case of guaiacol, reported in Chapter (4), uptake was compared on OMS surfaces with different hydrophobic functional groups. The key parameter found was that maximizing the amount of hydrophobic functional groups increases guaiacol uptake, but the interfacial surface must concurrently be wettable in aqueous solution. OMS materials were compared and shown to be on par with commercial adsorbents for phenolic molecule uptake, showing potential to improve material performance by incorporating similar functionalities. Chapter (5) describes the synthesis and characterization of colloidally stable, 18 nm silica nanoparticles functionalized with amine groups. It was shown that amine grafting did not impact particle size and that the dispersed particles were stable over 30 days. Ninhydrin, fluorescamine, and carboxylic acid binding showed that the amines are present and accessible on the silica surface. These novel particles could be used in a range of nanotechnology applications. / 1 / Peter Miller