Photocatalytic Enhancement of Anatase Supported on Mesoporous Modified Silica for the Removal of Carbamazepine

Abstract

TiO2 is the most used material for the photocatalytic removal of organic pollutants in aqueous media. TiO2, specifically its anatase phase, is well-known for its great performance under UV irradiation, high chemical stability, low cost and non-toxicity. Nevertheless, TiO2 presents two main drawbacks: its limited absorption of the visible spectrum; and its relatively low specific surface area and pore volume. Regarding the latter, several works in the literature have addressed the issue by developing new synthesis approaches in which anatase is dispersed and supported on the surface of porous materials. In the present work, two series of materials have been prepared where anatase has been supported on mesoporous silica (MSTiR%) in situ through a hydrothermal synthesis approach, where, in addition to using tetraethoxysilane (TEOS) as a silicon precursor, three organotriethoxysilanes [RTEOS, where R = methyl (M), propyl (P) or phenyl (Ph)] were used at a RTEOS:TEOS molar percentage of 10 and 30%. The materials were thoroughly characterized by several techniques to determine their morphological, textural, chemical, and UV-vis light absorption properties and then the most promising materials were used as photocatalysts in the photodegradation of the emerging contaminant and antiepileptic carbamazepine (CBZ) under UV irradiation. The materials synthesized using 10% molar percentage of RTEOS (MSTiR10) were able to almost completely degrade (~95%), 1 mg L−1 of CBZ after 1 h of irradiation using a 275 nm LED and 0.5 g L−1 of catalyst dose. Therefore, this new synthesis approach has proven useful to develop photoactive TiO2 composites with enhanced textural properties.