A visible light FeS/Fe2S3/zeolite photocatalyst towards photodegradation of ciprofloxacin

Abstract

FeS and Fe2S3 semiconductors were coupled and supported onto clinoptilolite nanoparticles (CN) via sulfidizing of Fe(II) and Fe(III) exchanged CN. The composite was characterized by X-ray diffraction (XRD), scanning electron microscope-energy dispersive x-ray (SEM-EDX), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS) techniques. To study of the synergistic effects of supporting and coupling, the photocatalytic activities of FeS-CN, Fe2S3-CN and FeS-Fe2S3-CN catalysts were evaluated in the photodegradation of ciprofloxacin (CIP) aqueous solution. The ratio of FeS/Fe2S3 played an important role in the photocatalytic activity of the coupled systems, so the catalyst FF1 which ion exchanged in a solution containing 0.1 mol L−1 Fe(II) and 0.15 mol L−1 Fe(III) showed the best activity in the degradation of CIP. To study the interactions of the experimental variables on the photocatalytic activity of the FeS-Fe2S3-CN catalyst, experiments were designed using response surface methodology (RSM) approach. The best results were obtained in the run with the following conditions: pH 3.7, catalyst dose of 2.8 g L−1, 3.8 mg L−1 of CIP during 102 min irradiation of the suspension. The satisfactory correlation coefficient (R2 = 0.9480) for the second order polynomial model, confirmed that the predicted data by RSM well agree with the experimental results.