Magnetically separable samarium doped copper ferrite-graphitic carbon nitride nanocomposite for photodegradation of dyes and pharmaceuticals under visible light irradiation

Abstract

Photocatalysis suffers two major drawbacks, namely the separation of the photocatalyst from treated water and the utilisation of expensive UV light. This has limited its application on an industrial scale. A novel nanocomposite of CuSm0.06Fe1.94O4@g-C3N4 with exceptional magnetic, electrochemical, and optical properties was synthesised using the hydrothermal method. The ratio of CuSm0.06Fe1.94O4 and g-C3N4 was optimised. Sm-CFGNC-3 (3: 1) was found to exhibit the highest photodegradation efficiency of 95.7% towards methyl orange (MO) in 90 min at pH 3.5, using visible light. In addition, 90.1% degradation of MO was observed in the scaled-up experiment, while high MO degradation efficiencies were also obtained for the spiked raw water from the Rand water treatment plant (83.4%) and Hazelmere treatment plant (76.6%). Furthermore, good removal efficiencies were obtained during the photodegradation of dyes (Congo red, tartrazine, Metanil yellow) and pharmaceuticals (carbamazepine, zidovudine, acetaminophen). The influence of various reaction parameters, such as catalyst amount, pH, dye concentration, oxidant effect, trapping experiments, catalyst reusability, and reaction mechanism, were investigated. Lastly, the reusability study showed a minimal loss in photocatalytic performance after 4 cycles, and the nanocomposite was easily separated from the treated water using a magnet. Thus, the synthesised nanocomposite is a potential candidate for the application of photocatalysis at an industrial scale.