Organic versus Hybrid Molecularly Imprinted Polymer Adsorbents: Structure–Selectivity Trade-Offs in Progesterone Removal from Water

High Resolution Image Download MS PowerPoint Slide The increasing occurrence of endocrine-disrupting compounds (EDCs) in aquatic environments demands efficient removal strategies. This study evaluated organic and hybrid molecularly imprinted (MIP) and nonimprinted polymers (NIP) as adsorbents for progesterone removal from aqueous media. Materials were characterized by thermogravimetric analysis, infrared spectroscopy, and scanning electron microscopy. Adsorption studies revealed optimal performance at pH 4, with rapid equilibrium within 120 s, governed by pseudo-second-order kinetics and dual-site Langmuir–Freundlich behavior, indicating the coexistence of specific and nonspecific binding sites. The organic imprinted polymer (MIP-O) achieved the highest capacity (22.345 mg g –1 ), with a ∼15% advantage over nonimprinted counterparts, while hybrid materials (MIP-H and NIP-H) exhibited comparable performance, indicating reduced imprinting efficiency. Comprehensive thermodynamic analysis confirmed entropy-driven adsorption at elevated temperatures, while computational modeling revealed that binding is governed by cooperative hydrogen bonding between polymer carboxylic acid groups and progesterone carbonyls (Δ E = −18.5 kcal mol –1 ). The MIP-O also exhibited satisfactory reusability, retaining approximately 68% of its adsorption capacity after six adsorption–desorption cycles. These findings demonstrate that organic molecular imprinting provides superior selectivity and performance for steroidal contaminant removal, offering rational design principles for advanced water treatment adsorbents.