Combined Removal of Pemetrexed Drug Using Adsorption and Photocatalytic Degradation from Polluted Water

Phenyl-substituted imidazoles, such as pemetrexed (PEME), pose substantial environmental risks due to their capacity for prolonged persistence within aquatic ecosystems. This study evaluates a combined adsorption-photocatalysis approach using TiO۲/UV-C for PEME removal, optimizing key parameters including pH (۴.۰–۸.۰), adsorbent dosage (۰.۱۲۵-۱.۰ g TiO۲), and initial PEME concentration (۲۵-۲۰۰ ppm). The findings reveal optimal adsorption efficacy (۹۲.۶%) at a pH of ۴.۰, propelled by electrostatic attraction between protonated TiO₂ (Ti–OH₂⁺) and anionic PEME. Photocatalytic degradation further enhanced removal (۹۸.۷% at pH ۴.۰) through hydroxyl radical (•OH) generation under UV-C irradiation. The equilibrium data demonstrated a strong correlation with the Freundlich isotherm (R² > ۰.۹۸), indicating multi-layer adsorption on heterogeneous TiO₂ surfaces. Temperature variations ranging from ۱۵ to ۴۰ °C exhibited an insignificant impact, while elevated doses of TiO۲ demonstrated a positive correlation with enhanced degradation. The TiO۲/UV-C system has been demonstrated to be a scalable and efficient solution for PEME-contaminated water, particularly under acidic conditions, thereby advancing the application of advanced oxidation processes (AOPs) for the treatment of pharmaceutical wastewater.

Keywords:

Pemetrexed , Adsorption , Photocatalysis , TiO₂ , Advanced oxidation processes (AOP’s) , Water Treatment