Highly-controlled grafting of mono and dicationic 4,4'-bipyridine derivatives on SBA-15 for potential application as...

This work describes a highly controlled post-grafting of mono and dicationic 4,4'-bipyridine alkoxysilane derivatives (Bipy(+) and Bipy(2+)) onto the surface of an ordered mesoporous silica, SBA-15. The materials obtained are designated as SBA-15/Bipy(+)Cl(-) and SBA-15/Bipy(2+)Cl(2)(-), both possessing chloride as counter ion. The regular arrangement of uniform pores of this inorganic matrix is likely to ensure good accessibility to the active centers (electron acceptors) attached to the surface. The materials are excellent adsorbents due to the ability of the functional groups to retain copper chlorides on their surfaces as anionic complexes (CuCl(2+n)(n-)) in ethanol. From the adsorption, results it was possible to probe the functional surface monolayer of the materials, which present a highly homogenous distribution of functional groups inside the ordered SBA-15 channels, with an exchange efficiency of 93% for SBA-15/Bipy(+)Cl(-) and 94% for SBA-15/Bipy(2+)Cl(2)(-). Both adsorbent materials are potentially useful in the pre-concentration and further analysis of Cu(II) present in trace amounts in ethanol, extensively used as an automotive fuel in Brazil.