Efficient oxytetracycline removal using poly(DMAEMA)@TiO2 nanocomposite hydrogel: real wastewater application from a cattle farm and water quality improvement

Abstract Wastewater from cattle farms, often containing antibiotics and other pharmaceuticals, poses a significant threat to water quality and environmental health. In this study, a poly(2-dimethylaminomethyl methacrylate) hydrogel incorporating TiO 2 nanoparticles was synthesized and optimized for the effective removal of oxytetracycline, a widely used antibiotic, from water and cattle farm wastewater. The adsorption was optimized by evaluating pH, adsorbent dosage, and contact time, achieving a maximum adsorption capacity of 770.54 mg g⁻ 1 at pH 7, with equilibrium established in just 30 min. The adsorption data followed the Langmuir isotherm model, indicating monolayer adsorption, and pseudo-second-order kinetics, suggesting chemisorption as dominant mechanism. The thermodynamic analysis confirmed that the process was spontaneous and exothermic, with higher efficiency observed at lower temperatures. Fourier Transform Infrared Fourier Transform Infrared Spectroscopy confirmed that electrostatic interactions and hydrogen bonding played key roles in adsorption. The prepared nanocomposite hydrogel maintained over 80% of its adsorption efficiency after six reuse cycles, with X-ray diffraction (XRD) analysis confirming its structural stability and crystallinity. When applied to real wastewater samples, the material significantly reduced pollutant levels, including Chemical Oxygen Demand (640–255 mg L −1 ) and Biochemical Oxygen Demand (215–63 mg L −1 ), conductivity (980–530 µS cm −1 ), sulfate (1253–96 mg L −1 ) and total phosphorus (2.125–0.458 mg L −1 ). These results show that the prepared nanocomposite hydrogel is a highly effective and environmentally friendly material for the rapid removal of antibiotics and the comprehensive improvement of water quality in complex wastewater systems. Graphical abstract