Photocatalytic removal of naphthalene (C10H8 ) from aqueous environments using sulfur and nitrogen doped titanium dioxide (TiO2 -N-S) coated on glass microbullets in presence of sunlight

Abstract

Background and aims: Due to their toxicity and carcinogenic effects, polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (C10H8 ) are regarded as hazardous compounds for both humans and the environment, and it is essential to remove these contaminants from the environment. The present study aimed to remove naphthalene from a synthetic aqueous environment using sulfur and nitrogen doped titanium dioxide (TiO2 -N-S) nanoparticles (NPs) immobilized on glass microbullets under sunlight. Methods: In this experimental study, TiO2 -N-S NPs were synthesized using sol-gel process. The structure of NPs was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and differential reflectance spectroscopy (DRS). In addition, using statistical analyses, the effects of parameters such as the initial concentration of naphthalene, pH, contact time, and the optimal conditions on naphthalene removal were investigated. Results: XRD patterns and SEM images of the samples confirmed the size of synthesized particles in nanometer. The EDX and DRS spectra analysis showed the presence of two elements (sulfur and nitrogen) and the optical photocatalytic activity in the visible region, respectively. The maximum level of naphthalene removal in the presence of sunlight was obtained to be about 93.55% using a concentration of 0.25 g of thiourea immobilized on glass microbullets at pH=5 and contact time of 90 minutes. Conclusion: The rate of naphthalene removal using the immobilized TiO2 -N-S on glass microbullets was 93.55% in optimal conditions. Therefore, this method has an effective potential for naphthalene removal, and can be used to remove naphthalene from industrial wastewater.