Fe₃O₄/SiO₂/TiO₂ nanoparticles for photocatalytic degradation of 2-chlorophenol in simulated wastewater.

Photocatalysis has emerged as an advance and environmental-friendly process for breakdown of organic contaminants in wastewater. This work reports facile synthesis and characterization of stable magnetic core-shell-shell Fe3O4/SiO2/TiO2 nanoparticles and their effectiveness for photocatalysis. The surface morphology, crystal structure, and chemical properties of the photocatalyst were characterized by using scanning electron microscope (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and nitrogen physisorption. Stability of synthesized nanoparticles in aqueous medium was tested by leaching test. The photocatalytic degradation of 2-chlorophenol was investigated and reaction parameters for best catalyst performance were optimized. Catalyst dose of 0.5 g/L under optimized conditions produced complete degradation of 25 mg/L 2-chlorophenol (2-CP) within 130 min of 100-W ultraviolet (UV) irradiation while 97.2 % degradation of 50 mg/L 2-CP was achieved within 3 h. The rate of photocatalytic degradation was determined by considering pseudo first-order kinetics and Hugul's kinetic equations. The Hugul's kinetics was found to provide a better interpretation of the experimental results than the generally adopted pseudo first-order reaction kinetics.