Density Functional Study on Interactions of Ti‐Porphyrin and its Derivative With Pharmaceutical Drugs for Wastewater Remediation

ABSTRACT Pharmaceutical pollutants pose a significant environmental threat due to their persistence in water bodies and potential ecological hazards. This study explores the adsorption and sensing capabilities of titanium porphyrin (TP) and its carboxyphenyl‐functionalized derivative (TCP) for removing four pharmaceutical drugs: 5‐fluorouracil (5‐FU), metronidazole (MNZ), flutamide (FLU), and favipiravir (FVR). Using Density Functional Theory (DFT) calculations, key adsorption parameters, such as adsorption energy, charge transfer, and electronic structure modifications, were analyzed to understand drug‐adsorbent interactions. The results demonstrate that both TP and TCP exhibit strong adsorption affinities, with TCP showing enhanced performance as the functional groups facilitate additional interactions between the drug and the porphyrin system. Quantum theory of atoms in molecules (QTAIM) and non‐covalent interaction (NCI) analysis confirm the presence of significant charge redistribution and stabilizing interactions. Moreover, solvation studies confirm the stability and efficiency of TP and TCP in aqueous environments, reinforcing its potential as a promising adsorbent for pharmaceutical pollutants. The observed red shift in absorbance spectra for all investigated drugs by applying the TD‐DFT approach corroborate the sensing performance of TP and its functionalized derivative.