Here we report that sulfonated crystal-like benzene-silica is much more robust and active than conventionally used periodic mesoporous silica for catalyzing aqueous organic reactions.

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In the present work the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium was investigated. The novel organic-inorganic material was synthesized via a sol-gel method through hydrolysis and co-condensation reactions. Its structure was characterized by means of SEM, XRD and FTIR. Based on the data obtained the most probable cross-linking mechanism for the derived xerogel was proposed. The characterization of its texture parameters was carried out by low-temperature adsorption of nitrogen. The adsorption properties of this material with respect to Cu(II), Cr(III) and Pb(II) ions from single-component aqueous solutions and multi-component aqueous solutions containing also Cd(II) and Fe(III) were evaluated. The effect of contact time, acidity of initial solutions and metal ion concentrations was investigated using the batch method. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. In all cases the adsorption was significantly affected by the pH value. Equilibrium modelling data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models. Best fit was observed for Langmuir model, which showed determination coefficients greater than 0.992 for all ions studied. The maximum adsorption capacities for single- and multi-component adsorption were calculated.

This work investigates the influence of the precursor trimethylsilil isocyanate on the sol-gel synthesis of hybrid materials. The obtained Si-O-C-N network is additionally modified by titanium and zirconium alcoxypropoxides in the range of 10 to 30 wt.%. The structure of the obtained hybrid materials before and after pyrolysis up to 1100 • C was investigated by methods of XRD, FTIR and 29 Si MAS NMR. We established that the hybrid structure was stable up to 600 • C based on IR study. The structural transformation of the hybrid materials into oxycarbonitrogen system started at 800 • C. The network of the hybrids modified by titanium remained stable and amorphous up to the final temperature of the pyrolysis (1100 • C) compared to the gels modified by more than 10 wt.% Zr. It was confirmed by XRD analysis that the last mentioned are nanocomposite materials, built from carbooxynitrogen vitreous matrix and ZrO 2 -nanocrystals (tetragonal). The NMR method verified the presence of heterometallic bonds (Si-O-Ti and Si-O-Zr) and Q 4 , ZrQ 3 or TiQ 3 , NSiO 3 and D structural units in the gels.

Nanostructured hybrid materials containing Al 2 O 3 were synthesized via a sol-gel method through hydrolysis and co-condensation reactions using trimethylsilyl isocyanate (TMSI) as a new silica source in the presence of tetramethoxysilane (TMOS) and three different quantities (