Photocatalytic degradation of tetracycline antibiotic and organic dyes using biogenic synthesized CuO/Fe 2 O 3 nanocomposite: Pathways and mechanism insights

Abstract

Tetracycline (TC) is a frequently administered antibiotic in many countries, due to its low price and excellent potency. However, certain antibiotics can be hazardous to living creatures due to their accumulation by complexation with metal ions which can contribute to teratogenicity and carcinogenicity. In this investigation, ferrous oxide-copper oxide nanocomposite (CuO/Fe2O3 nanocomposite) were synthesised employing Psidium guajava (P. guajava) leaf extract as a reductant and a capping agent in an environment friendly and economical green synthesis method. The as-synthesized CuO/Fe2O3 nanocomposite were comprehensively characterized using various sophisticated techniques and their efficiency as photocatalyst for degradation of TC antibiotic and toxic dyes i.e. rhodamine B (RhB) and methylene blue (MB) was investigated. The CuO/Fe2O3 nanocomposite exhibited exceptional efficiency for degradation of TC antibiotic (88% removal in 80 min), RhB (96% removal in 40 min) and MB (93% elimination in 40 min) with apparent rate constant of 0.048, 0.068 and 0.032 min− 1. In the degradation experiments, photocatalytic activities of CuO/Fe2O3 nanocomposite were studied by varying different factors such as time of contact, catalyst dose and solution pH. The role of reactive species in antibiotics and dye degradation was validated by radical scavenging studies which indicated that .OH radical has a critical role in photocatalytic decomposition. Furthermore, liquid chromatography-mass spectrometry (LC-MS) investigations were employed to anticipate a plausible mechanism for TC degradation.