Photocatalytic and adsorption properties of TiO₂-pillared montmorillonite obtained by hydrothermally activated intercalation of titanium polyhydroxo complexes

Abstract

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25.

Synergistic Effect of Dielectric Barrier Discharge Plasma and TiO2-Pillared Montmorillonite on the Degradation of Rhodamine B in an Aqueous Solution

“…To eliminate any effect of sorption processes, the photocatalytic reactor and the DBD reactor were equilibrated for 30 min [31] and 5 min, respectively, before starting the process. The reactor vessels were thoroughly cleaned between experiments.…”

“…The TiO 2 -pillared montmorillonite possesses a highly developed specific surface area and exhibits high activity in various photocatalytic processes, including photolysis of organic dyes [30]. Recently we proposed and successfully applied a new approach to the synthesis of TiO 2 -pillared montmorillonite with a high degree of crystallinity for the TiO 2 pillars (nanocrystals) representing a mixture of the anatase and rutile phases, and with improved adsorption and photocatalytic activities as a result of hydrothermally activated intercalation of titanium polyhydroxocomplexes [31]. Moreover, when obtaining TiO 2 -pillared MM, along with hydrothermal activation of the intercalation of titanium polyhydroxocomplexes we have used preliminary mechanical treatment of the original substrate [32].…”

Structural and Thermal Properties of Montmorillonite/Ionic Liquid Composites

“…Interlayer cations in MMT are capable of ion exchange, and can be replaced by other inorganic or organic ions, metal nanoparticles, metal oxides, or metal–organic compounds [6,7,8]. This allows for the creation of composite nanomaterials with new properties, such as photocatalytic, catalytic, adsorption, mechanical, and thermal stability.…”

Photocatalytic cementitious material for self-cleaning and anti-microbial application

“…Although TiO 2 -anatase has the lowest surface area, this material showed the highest adsorption capability under dark conditions. The previous study demonstrated that surface charges of TiO 2 material play an important role in the adsorption process (Dai, 1994, Karaca et al, 2008, Butman et al, 2018. Electrostatic interactions between the organic dye and TiO 2 material have been shown to be an important factor controlling the interaction mechanism of contaminant/dye particles to TiO 2 surfaces.…”