Defect State Modulation of TiO<sub>2</sub> Nanostructures for Photocatalytic Abatement of Emerging Pharmaceutical Pollutant in Wastewater Effluent
Prasenjit Kar, Deepanshu Aggarwal, Komal Shukla, Raju Kumar Gupta
Abstract
Rapid industrialization has resulted in a significant presence of pharmaceutical compounds in aqueous effluents, and therefore, effluents must be effectively treated before discharging them to water bodies. The removal of emerging pharmaceutical pollutants in wastewater using TiO 2 via photocatalysis technique is limited because of its wide bandgap (≈3.2 eV). Herein, defect state modulation of TiO 2 for degradation of pharmaceutical pollutant “antipyrine” under visible light irradiation is investigated. A simple hydrothermal technique for synthesis of TiO 2 microspheres (average diameter ≈2.94 μm), followed by chemical reduction method for formation of defective‐TiO 2 microspheres using NaBH 4 under an inert atmosphere for different durations (3, 5, and 8 h) is used. Defective‐TiO 2 microspheres are utilized for photocatalytic degradation of antipyrine under visible light illumination. Improved photocatalytic activity for the defective‐TiO 2 samples is observed due to a reduction in bandgap as well as incorporation of Ti 3+ , acting as a trap site and resulting in reduced electron‐hole recombination. For practical application, a continuous prototype reactor comprising defective‐TiO 2 particles immobilized over glass beads is developed and efficient photocatalytic degradation of antipyrine under continuous operation is observed. Excellent recyclability and efficient photocatalytic degradation indicate a promising future for the developed defective‐TiO 2 particles toward real‐world wastewater treatment applications.