Surface modification of magnetic nanoparticles to remove tetracycline from water samples

Tetracyclines are one of the most widely used antibiotics which are utilized in both human and veterinary treatments. More than 75% of tetracyclines are excreted in their original form and derivatives and released into the environment via human and animal urine and feces, which cause a serious threat to the ecosystem and human health. There are several conventional techniques to remove tetracyclines from environments such as adsorption and degradation. However, the main disadvantage of these methods is the lack of the selectivity. At that point the molecular imprinting, a method to prepare tailor made materials with high specific selectivity and binding capacity is a useful alternative. In this work, tetracycline imprinted thin films were prepared on the magnetic iron (III) oxide nanoparticles (MNP) by admicellar polymerization of styrene and divinylbenzene. The detailed structural and physical characterization of modified magnetic nanoparticles was carried out by FTIR, XPS, XRD, TEM and BET. The size of the magnetic nanoparticles before and after modification was determined as approximately 35 nm and 115 nm, respectively. Binding properties were evaluated by employing adsorption isotherms. The specific selectivity of the tetracycline imprinted polymers was evaluated for structurally similar tetracyclines. The imprinting factor was determined as 3.41, 1.55, 1.52 and 1.23 for tetracycline, oxytetracycline hydrochloride, doxycycline hyclate and chlorotetracycline, respectively. The binding capacity of the molecularly imprinted polymer modified MNP was investigated for tap water and natural waters samples. The adsorption percentage of tetracycline was determined as 83.2, 66.3, 54.7 and 51.5 for ultra-pure water, tap water and natural water samples as Pazar Creek and Kızılırmak, respectively.