Removal of environmentally toxic sulfamethoxazole waste using TiO2-graphite systems and a tailor-made LED photoreactor: Unraveling the role of spectra-matching

Abstract

Active pharmaceutical ingredients cause hazards to the aquatic environment. Taking this into account, it is necessary to produce tailor-made photocatalytic systems for better photocatalytic performance. Herein, we present a novel concept of matching the spectra of TiO2-graphite photocatalysts and UV-LED light source for enhanced elimination of sulfamethoxazole. The photocatalysts were obtained by a one-step in situ microwave procedure. During the research, the influence of changes in graphite content on the crystal structure, surface area development, and optical properties of the synthesized photocatalysts was determined. The properties of TiO2-graphite systems were verified based on the XPS analysis, active species trapping experiments, and the measurement of band edge positions. It was found that the presence of graphite causes a red shift in the absorption spectra. For this reason, a tailor-made LED photoreactor was designed to match the spectrum of the photocatalyst and the light source. Photocatalytic studies showed a higher sulfamethoxazole removal efficiency for TiO2-graphite (TiO2-G) systems compared to the reference TiO2. In addition, it was shown that the obtained TiO2-G systems exhibit high reusability. Therefore, the developed novel spectral matching approach may hold promise for introducing the photocatalytic process to wastewater treatment plants.