Sonophotocatalytic degradation of sulfamethoxazole using lanthanum ferrite perovskite oxide anchored on an ultrasonically exfoliated porous graphitic carbon nitride nanosheet

Abstract

The lanthanum ferrite perovskite (La_0.8FO) was synthesized using a citric combustion route and then modified with a porous graphitic nitride nanosheet via the wet impregnation-assisted ultrasonic method to produce La₀.₈FO@PgNS. Various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet diffuse reflectance spectroscopy (UV-DRS), and Tauc plot analysis were employed to confirm the functional moieties, crystallinity, phase change, morphology, composition, and bandgap of La._0.8FO and La₀.₈FO@PgNS. La_0.8FO and La₀.₈FO@PgNS were used for the sonophotocatalytic oxidative degradation of sulfamethoxazole (SMX) under low energy and ultrasound wave frequency in the presence of visible light. La_0.8FO and La₀.₈FO@PgNS exhibited a sonophotocatalytic degradation capacity of 52.06 and 99.60%, respectively. Furthermore, the rate constant at the optimum condition of pH 7 and 5 mg L⁻¹ concentration was 0.01343 and 0.01494 min⁻¹ for La_0.8FO and La₀.₈FO@PgNS, respectively. The integration of sonolysis and photocatalysis in the remediation process of SMX resulted in a synergy of 2.5-fold. Ultrasonic waves and hydroxyl and superoxide radicals are the main species governing the degradation process while La₀.₈FO@PgNS was stable over 8 cycles, proving to be a sustainable material for environmental remediation.