Ultrasonic preparation of mesoporous silica using pyridinium ionic liquid

Abstract

2Mesoporous silica matrices have been prepared via classic acid catalyzed and sono-catalyzed sol-gel routes. Tetramethoxysilan (TMOS) and methyl-trimethoxysilane (MTMS) were used as silica precursors, and N-butyl-3-methylpyridinium tetrafluoroborate ([bmPy][BF4]) was employed as cosolvent and pore template. The ionic liquid (IL) to silica mole ratio was varied between 0.007 and 0.07. Nitrogen adsorption-desorption and small-angle neutron scattering measurements have been used to characterize the obtained materials. The ionic liquid played the role of catalyst that affected the formation of the primary xerogel particles, and changed the porosity of the materials. Ultrasound treatment resulted in microstructure change on the level of the colloid particle aggregates. In comparison with IL containing xerogels, the IL containing sonogels show increased pore diameter, bigger pore volumes and diminished surface areas.

Silica-Coated Magnetic Nanocomposites for Pb2+ Removal from Aqueous Solution

“…Fitting the data to the phenomenological Beaucage model [23] provides the size of the scattering entities collected in Table 4. In these composite materials, the average sizes of the embedded iron oxide particles (around 10 nm; XRD data and earlier studies [27]) and of the primary silica particles formed in the sol-gel process (5-10 nm [28,29]) are similar, therefore the applied model gives only an average size of these two All data show a characteristic scattering pattern of materials having structural inhomogeneities on two characteristic sizes: the smaller sizes inhomogeneities-pores or particles produce a plateau or shoulder in the q range 0.3-0.8 nm −1 that corresponds to a size range of 5-30 nm, and a power law-like scattering that extends below the low q cut-off of the investigated q range, indicating a structural level larger than 200 nm. Fitting the data to the phenomenological Beaucage model [23] provides the size of the scattering entities collected in Table 4.…”

“…Fitting the data to the phenomenological Beaucage model [23] provides the size of the scattering entities collected in Table 4. In these composite materials, the average sizes of the embedded iron oxide particles (around 10 nm; XRD data and earlier studies [27]) and of the primary silica particles formed in the sol-gel process (5-10 nm [28,29]) are similar, therefore the applied model gives only an average size of these two structural components, that is the iron oxide particles and the primary silica particles. The monotonous increase of their average size or radius of gyration (Table 4) with an increasing amount of iron oxide shows that the synthesis method used permits to change continuously the textural properties of the materials.…”

Efficient Photocatalytic Degradation of Ibuprofen under Visible Light Irradiation Using Silver and Cerium Co‐Doped Mesoporous TiO2

“…The N 2 adsorption‐desorption isotherms and pore size distribution of prepared catalysts are shown in Figure . Pure TiO 2 and doped mesoporous TiO 2 catalysts exhibit type IV adsorption ‐isotherms characteristic of mesoporous materials according to the IUPAC …”

Small-angle scattering investigation of silica xerogels and sonogels prepared with ionic liquid pyridinium tetrafluoroborate

“…Two series of samples (see Table 1): classic xerogels and sonicated gels were prepared and details are given in a previous paper [19]. In brief, 0.13 moles of TMOS, 1.15 moles of distilled water, 0.4 moles of acidic water 4 ] was added into the reaction mixture in an amount to obtain IL/Si molar ratios from 0.007 to 0.07.…”

“…The samples were synthesized in acidic conditions, with varying IL/Si molar ratios. Nitrogen adsorption, SANS and infrared results on these materials have been reported recently [19]. The particular choice of the precursors and ionic liquid was motivated by several considerations.…”