Enhanced adsorption of norfloxacin on modified TiO2 particles prepared via surface molecular imprinting technique

For norfloxacin removal in aquatic environment, TiO2 particles (P25) were modified via surface molecular imprinting technique to improve the adsorption property and sustainable use by photocatalytic regeneration. Orthogonal experiment was adopted to quantify the significance of preparation factors and determine the optimum preparation conditions. The adsorption of norfloxacin on the molecular imprinted particles (MIPs), the non-imprinted particles (NIPs), and P25 fitted the second-order adsorption model and Langmuir model well. The MIPs showed a higher adsorption capacity toward norfloxacin than the NIPs and P25. The adsorption rate constant, maximum adsorption capacity, and Langmuir constant of the MIPs toward norfloxacin were 0.49 g mg−1 min−1, 2.99 mg g−1, and 2.4 L mg−1, respectively. Removal efficiencies for norfloxacin, ciprofloxacin, carbamazepine, and phenol by the MIPs were 76.99, 78.81, 7.87, and 2.68%, respectively, which indicated that the MIPs had higher affinity toward norfloxacin and fluoroquinolones with similar structures. Moreover, the MIPs exhibited the photocatalytic property and could be regenerated by UV irradiation with stable removal efficiency for norfloxacin in five adsorption–regeneration cycles.