Silver-containing composites based on copolymers of β-cyclodextrin and TiO2 for enhanced photocatalytic degradation of methyl orange in environmental water

Abstract

This study aims to develop effective photocatalysts by combining the photocatalytic properties of TiO₂ and Ag nanoparticles (AgNPs) with the adsorption ability of β-cyclodextrin-containing polymers (CDPs). For this purpose, TiO₂/CDP/AgNP hybrid catalysts were prepared via radical and thermal polymerization of cyclodextrin derivatives with trimethylolpropane trimethacrylate on the TiO₂ surface, followed by introduction of 1 wt% silver nanoparticles into their bulk via reduction of Ag⁺ salts under UV irradiation or using NaOH. The structure of the nanocomposite photocatalysts was investigated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA), and particle size distribution was determined via dynamic light scattering (DLS). The photocatalytic degradation process was monitored via UV-vis spectroscopy in an aqueous environment at pH 2.5. The best photodegradation results for methyl orange (MO) were obtained using samples prepared from β-CD methacrylate and silver methacrylate. In this case, complete decolorization of the MO solution was achieved within 10 min at pH 2.5, which is 7.5 times faster than that achieved by pure TiO₂ and 4 times faster than that that achieved by the TiO₂/CDP sample.