Self-assembled titania–silica–sepiolite based nanocomposites for water decontamination

Abstract

This work describes the preparation of microchannel structured monolithic pieces by the “ice-segregation induced self-assembly” (ISISA) process. The monoliths exhibit a hierarchical structure composed of homogeneously mixed colloidal silica resulting from hydrolysis and condensation of an alkoxysilane precursor (e.g., TEOS) and TiO₂ polycrystalline nanoparticles adsorbed onto sepiolite fibres. The combination of such a different species into a single macroporous structure provides a multifunctional material capable of water decontamination by pollutant removal from aqueous media (via adsorption on sepiolite) and subsequent elimination by UV irradiation (via photocatalytic oxidation on TiO₂nanoparticles). The performance of the resulting materials has been studied using two organic compounds often present in wastewater such as p-nitrophenol (PNP) and methylene blue (MB).