Magnetic cobalt ferrite/reduced graphene oxide (CF/rGO) porous balls for efficient photocatalytic degradation of oxytetracycline

Abstract

Photocatalytic degradation is an effective technique for removing antibiotics from contaminated water. The kernel of photocatalytic degradation lies in the design and preparation of high-performance and recyclable catalysts. Herein, magnetic porous cobalt ferrite/reduced graphene oxide (CF/rGO) balls were prepared by calcination of spherical composites obtained via modified microfluidic method for effective photocatalytic degradation of oxytetracycline (OTC). The strong interfacial interaction between rGO and cobalt ferrite nanoparticles in porous balls enhanced electron transfer, charge separation and light absorption. Porous spherical structure was favorable for light harvesting. The catalyst could rapidly and efficiently absorb OTC. These characteristics were beneficial to the enhancement of photocatalytic efficiency. The optimized sample (CF/rGO-0.2) exhibited an excellent apparent rate constant (0.0410 min−1) for OTC degradation under visible light irradiation, which was 3.73 times that of CF/rGO-0 (0.0110 min−1). CF/rGO-0.2 had excellent stability in cycle experiments and could be quickly recovered by magnets. The trapping experiments showed that hole (h+) and superoxide radicals (·O2-) acted an extremely important role in degradation of OTC, thus suggesting a possible photocatalytic reaction mechanism. This work provides a potential photocatalyst for antibiotic removal from water.