2. Experimental
2.1. Preparation of the SBA-15 support
Siliceous SBA-15 mesoporous material was synthesized according
to the procedure described by Flodström and Alfredsson [38].
The pluronic triblock copolymer (BASF, EO20–PO70–EO20, P123)
was used as the structure-directing agent and tetraethyl orthosilicate
(TEOS, 98%, Aldrich) as a source of silica. In a typical synthesis,
the triblock copolymer was dissolved in a mixture of deionized
water (High Purity, specific conductance of 0.2 lOhm1 cm1)
and 4 M hydrochloric acid solution (pH 0.6) in a Teflon bottle while
the solution was heated at 75 C for 4 h. After this, the required
amount of silica precursor (TEOS/P123 M ratio of 58) was added
drop wise to the solution under vigorous stirring at 35 C for
1 min and kept under slow stirring for 24 h. The synthesis gel
was subsequently transferred into polypropylene containers and
kept at 85 C for another 24 h under static conditions. The final
product was filtered, washed thoroughly with distilled water,
and thereafter dried in air at 100 C for 12 h. The polymer was removed
by calcination in air at 500 C for 6 h.