Photochemical degradation of an anionic surfactant by TiO2 nanoparticle doped with C, N in aqueous solution

Abstract

Novel C,N-doped TiO₂ nanoparticles were prepared by a solid phase reaction. The catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that crystallite size of synthesized C,N-doped TiO₂ particles were in nanoscale. UV light photocatalytic studies were carried out using sodium naphthalenesulfonate formaldehyde condensate (SNF) as a model pollutant. The effects of initial concentration of surfactant, catalyst amount, pH, addition of oxidant on the reaction rate were ascertained and optimum conditions for maximum degradation was determined. The results indicated that for a solution of 20 mg/L of SNF, almost 98.7% of the substance were removed at pH ~ 4.0 and 0.44 g/L photocatalyst load, with addition of 1 mM K₂S₂O₈ and irradiation time of 90 min. The kinetics of the process was studied, and the photodegradation rate of SNF was found to obey pseudo-first-order kinetics equation represented by the Langmuir–Hinshelwood model.