“…Zirconia and titania were developed to replace silica as packing materials for high-pressure liquid chromatography (HPLC) (Werber et al, 1990;Blackwell and Carr, 1991). These adsorbents were used to separate structural isomers, amino acids and proteins by HPLC (Werber and Carr, 1990;Blackwell and Carr, 1992) and to separate peridines by ligand-exchange gas chromatography (GC) (Fujimara and Ando, 1977). Sol-gel prepared alumina adsorbents have also been employed as flue-gas cleaning adsorbents and proved to be superior to the conventional adsorbents with respect to their chemical and mechanical stability (Hakvoort et al, 1987;Duisterwinkel et al, 1989).…”