Controlling the Microporosity of SBA-15 Silicate Material
by Background Salt Solution¹

V. A. Parfenov^a, I. V. Ponomarenko^a, S. M. Zharkov^b, and S. D. Kirik^{a, b}

^aInstitute of Chemistry and Chemical Technology, Russian Academy of Sciences, Siberian Branch,
Akademgorodok 50/24, Krasnoyarsk, 660036 Russia

^bSiberian Federal University, pr. Svobodnyj 79, Krasnoyarsk, 660049 Russia
e-mail: jnz@icct.ru

Abstract—The structure of silicate material of the SBA-15 type has been studied under variable composition
of a salt solution in synthesis. Ammonium and sodium chlorides, as well as ammonium fluoride, introduced into
the composition of the reaction mixture both at the first stage of precipitation and at the second stage of the
thermal treatment (TT), have been used as the salt additives. The mesostructure was controlled by X-ray dif-
fraction, gas adsorption and transmission electron microscopy. It was found that the multiple increase of the
ionic strength of the solutions in the presence of chloride salts disrupt the stoichiometry of the silicate–surfac-
tant interaction at the first stage of formation of mesostructure and leads to the formation of an impurity of irreg-
ular structure. The ions of ammonium promote an increase in the microporosity of the silicate wall. The pres-
ence of sodium ions reduces microporosity. Small quantities of fluoride ions (F ^– : Si = 0.032) improve the order-
ing of the product at the stage of primary precipitation. At the ratio F ^– : Si = 0.16, the hexagonal mesostructure
is not formed. The introduction of fluorides at the TT stage leads to a decrease of the silicate pore wall thickness,
microporosity and hexagonality of the pore.

Keywords: mesoporous mesostructured silicates, SBA-15, X-ray diffraction, method of approaching continu-
ous electron density, transmission electron microscopy, N₂ adsorption

DOI: 10.1134/S1087659614010179

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