Unveiling the effect of SWCNT as the dopants of TiO2 in pharmaceutical mixture photocatalytic removal from water and wastewater

Abstract

Increased pharmaceuticals and personal care products usage increases their disposal. Low biodegradability, poor removal during conventional treatment, and long-range transport make them persistent pollutants. Removal of such pollutants is of great importance nowadays and requires advanced techniques. Photocatalysis using visible light is a promising method for detoxifying water and wastewater. In the presented studies the effect of Single-Walled Carbon Nanotubes (SWCNT) on the activity of TiO₂-SiO₂ was tested. The photocatalysts were characterized by high available surface area (280–525 m² g⁻¹), and reduced band gap energy (2.84–3.03 eV) suggesting good photocatalytic behavior under vis irradiation. The broad characteristics of the photocatalysis revealed that the greatest changes in the photocatalysts’ properties were noted when the amount of doped SWCNT was between 1.7–3.5 wt%. k₁ values ranged from 0.0038 min⁻¹ (ibuprofen), 0.0204 min⁻¹ (carbamazepine), 0.0626 min⁻¹ (oseltamivir), to 0.0783 min⁻¹ (metoprolol). The effect of inorganic ions, dissolved organic matter, and ionic strength were estimated. The process mechanism was examined using radical scavengers and the process was performed using tap water and treated wastewater. The results confirmed that obtained materials with enhanced surface area and porosity, abundance of surface functional groups, and visible light activation should reveal a great potential for pollutant removal.