Abstract

The present study aimed to investigate the photodegradation of ibuprofen (IPF) by using black N-TiO2 under visible LED illumination. The as-synthesized black N-TiO2 nanoparticles were characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectrometer (EDS) detector, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), UV visible diffuse reflectance spectroscopy (UV-DRS), and Brunauer-Emmett-Teller (BET) techniques. The potential photocatalytic activity of the synthesized nanoparticles was assessed by degradation and mineralization of IPF under visible LED light irradiation. Compared to N-TiO2, the black N-TiO2 exhibited higher degradation (96) and mineralization (81) efficiency for IPF under selected operational conditions. We observed that codoping of N and Ti3+ narrowed the band gap (2.1 eV) and decreased the recombination of photogenerated carriers. Pseudo-first order kinetic model was best fitted with the experimental results (R-2 > 0.99 for different IPF concentrations). Radical-scavenging tests showed that hydroxyl radicals ((OH)-O-center dot), holes (h(+)), and superoxide radicals (O-center dot(2)-) are involved in the photocatalytic degradation of IPF, however (OH)-O-center dot and O-center dot(2)- played more important roles. The energy consumption of the system for different initial IPF concentrations was around 16.6-38.7 kWh/m(3), indicating that the LED-black N-TiO2 process is energy-efficient. The results revealed that the photocatalytic activity of the black N-TiO2 is not changed much, even after 5 cycles, demonstrating its excellent photocatalytic stability and reusability. According to the findings, LED-black N-TiO2 process has the potential to be applied for facile removal of contaminants of emerging concern (CECs) such as IPF from water resources.