Background This research sheds light on one of the contaminants of the emerging concern, oxytetracycline (OTC), a commonly used antibiotic used to treat infections and diseases caused by bacteria. Numerous studies have shown that despite the use of various removal mechanisms, trace amounts of this substance remain in water. The accumulation of these trace amounts can negatively impact water quality and both microscopic and macroscopic organisms.Methods This study utilized adsorption as a successful and cost-effective method for removing OTC compounds using industrial waste, fly ash (FA). Ball milling and sonication have been applied to improve the adsorption capacity towards OTC. The developed materials were characterized using Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) techniques. The performance of OTC adsorption onto FA and its modified forms has been optimized using different parameters (solution pH, adsorbent dose, contact time, and OTC initial concentration).Results It is noticed that under the optimum conditions, the ball milling has improved the adsorption capacity of OTC to 5760.86 mg/g compared to pristine fly ash (1165.98 mg/g). On the other hand, the sonication process is not effective due to the washing of the main functional groups during the sonication process.Conclusions Therefore, this study is considered an environmentally friendly model where fly ash has been recycled to remove OTC, achieving sustainable water treatment and the circular economy.