Today, the use of antibiotics around the world poses many threats to the environment and humans. Antibiotics are potentially environmental pollutants that play an important role in causing pollution with the development of new technologies and increasing use of these products. Photodegradation of antibiotics is a promising way to solve the contamination of antibiotics in water. In this study, the photodegradation efficiency of nanocomposites of contaminants such as tetracycline and doxycycline antibiotics was investigated using nanocomposites of CoFe2O4@GO, MIL-101Fe (NH2), g-C3N4, MIL-101Fe (NH2) @g-C3N4 and MIL-101Fe (NH2) @ g-C3N4@ CoFe2O4 / GO. The best efficiency of degradation was obtained by MIL-101Fe (NH2) @g-C3N4@CoFe2O4/ GO (90% and 80% for tetracycline and doxycycline respectively). Photodegradation conditions of effective photocatalyst were optimized by experimental design (version 11) and results were found as follow: initial antibiotic concentration of 20 ppm, pH = 5, the dosage of photocatalyst 40 mg and irradiation time of 65 min. The quadratic model was proposed as a suitable model with coefficient of determination R2 = 0.9982, 0.962 for tetracycline and doxycycline respectively. The photocatalysts were characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), UV-Vis spectroscopy and Fourier transform infrared spectroscopy (FT-IR) techniques. Zeta potential was also used to determine the surface charge. The final products of degradation process were analyzed by 1HNMR, MS and UV-Vis spectroscopic techniques.
