Molecularly Imprinted Polymer with Photocatalytic Activity for the Adsorption and Degradation of Naproxen and Its Application in Real Water Samples

This research focused on the development and characterisation of molecularly imprinted polymers (MIPs) modified with titanium dioxide (TiO2) for the adsorption and photocatalytic degradation of sodium naproxen (NPX). Different percentages of TiO2 (5% and 25%) were tested and compared to non-imprinted polymers (NIPs). FT-IR analysis confirmed the interaction between methacrylic acid and TiO2, promoting the formation of specific binding sites and presenting a good imprinting factor. The results showed that the MIP with 5% TiO2 had the highest adsorption and retention capacity, attributed to the imprinting effect and the reduced interference from TiO2. The surface of the MIPs is heterogeneous, as it was indicated by the Freundlich isotherm model. The KF for the MIP with 25% of TiO2 was higher than for the materials with 5%; values for the MIP/TiO2 5% and the NIP/TiO2 5% KF were 4.808 and 4.163 (mg/g)(L/mg)1/n respectively, while for the MIP/TiO2 25% was 6.542 (mg/g)(L/mg)1/n and for the NIP/TiO2 25% it was 2.736 (mg/g)(L/mg)1/n. Kinetic studies followed the pseudo-second-order model, suggesting more active binding sites in MIPs. Photocatalytic experiments achieved 60% degradation, demonstrating the degradation performance of MIPs; however, this behavior is restricted by the slow degradation of NPX. The materials were evaluated using a water sample (Querétaro River, México); the sample was preconcentrated and analyzed, detecting a concentration of 0.332 mg/L of NPX. This finding highlights the MIPs’ potential application in environmental monitoring and treatment; nevertheless, due to the recalcitrant nature of NPX, MIPs should be used along with other advanced treatment methods to achieve effective removal.