Micrometric mesoporous spheres with textures possessing a relative high degree of ordering and incorporating up to 0.1 thiol function per siloxane unit have been synthesised through sol–gel, self-assembly and—for the first time—spray-drying processes. The sol preparation was optimised as a function of the final properties: morphology, texture, and proportion of thiol functions. A two step synthesis allows the positioning of these functions at the pore surface as proven in particular by ¹H solid state NMR. From Ag⁺ sorption experiments, we have shown that the thiol functions are also homogenously distributed in the sphere's volume and fully accessible to external chemical species. So these materials could be used for environmental remediation or metallic nano-particle syntheses. In order to increase the stability and applicability of the materials, different post-synthesis treatments have been studied. A thermal treatment under mild conditions is enough to preserve most of the properties. From the hydrothermal treatments tested, the use of ammonia is shown to be quite interesting for the modulation of the properties. In particular, hierarchical porosities and high specific surface areas have been created. The high degree of ordering observed for the smaller pores is accompanied by a re-ordering of the surfactant polar head groups as deduced from ¹⁴N NMR. Lastly, the synthesis can be extended under some conditions to other functions or to higher proportions of thiol functions (up to 0.2).

The magnetite nanoparticles were functionalized with silica shells bearing mercaptopropyl (monofunctional) and mercaptopropyl-and-alkyl groups (bifunctional) by single-step sol-gel technique. The influence of synthetic conditions leading to increased amounts of active functional groups on the surface and improved capacity in the uptake of Ag(I), Cd(II), Hg(II), and Pb(II) cations was revealed. The physicochemical properties of obtained magnetic nanocomposites were investigated by FTIR, Raman, XRD, TEM, SEM, low-temperature nitrogen ad-/desorption measurements, TGA, and chemical microanalysis highlighting the efficiency of functionalization and mechanisms of the preparation procedures. The removal of the main group of heavy metal cations was studied in dependence from the pH, contact time and equilibrium concentration to analyze the complexes composition for the large scale production of improved adsorbents. It was demonstrated that introduction of the alkyl groups into the surface layer prevents the formation of the disulfide bonds between adjacent thiol groups. The obtained adsorbents were employed to treat real wastewater from Ruskov, Slovakia with concentration of Fe 319 ng/cm³, Cu 23.7 ng/cm³, Zn 36 ng/cm³, Mn 503 ng/cm³, Al 21 ng/cm³, As 34 ng/cm³, Pb 5.8 ng/cm³, Ni 35 ng/cm³, Co 4.2 ng/cm³, Cr 9.4 ng/cm³, Sb 6 ng/cm³, Cd 5 ng/cm³. These materials proved to be highly effective in the removal of 50% of all metal ions, espeсially Zn, Cd, and Pb ions from it and turned recyclable, opening for their sustainable use in water purification.

Organic–inorganic hybrid adsorbents for separation of rare earth elements were prepared by grafting of amino phosphonic acid ligands onto mesoporous TiO₂. Their structure and capacity were elucidated using X-ray studies of molecular model compounds.