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 tio2/uv-c for peme removal, optimizing key parameters including ph (4.0–8.0), adsorbent dosage (0.125-1.0 g tio2), and initial peme concentration (25-200 ppm). the findings reveal optimal adsorption efficacy (92.6%) at a ph of 4.0, propelled by electrostatic attraction between protonated tio₂ (ti–oh₂⁺) and anionic peme. photocatalytic degradation further enhanced removal (98.7% at ph 4.0) through hydroxyl radical (•oh) generation under uv-c irradiation. the equilibrium data demonstrated a strong correlation with the freundlich isotherm (r² > 0.98), indicating multi-layer adsorption on heterogeneous tio₂ surfaces. temperature variations ranging from 15 to 40 °c exhibited an insignificant impact, while elevated doses of tio2 demonstrated a positive correlation with enhanced degradation. the tio2/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.