Development of a New Ion‐Imprinted Polymer (<scp>IIP</scp>) Using Dithizone as a Binding Agent for the Removal of Pb²⁺ From Real River Water Samples

ABSTRACT This work focuses on the selective removal of low concentrations of Pb 2+ using ion‐imprinted polymers (IIPs). Dithizone was selected as the binding agent due to its strong affinity for Pb 2+ . Simulations based on density functional theory (DFT) led to the selection of 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPSA) as the functional monomer. FTIR spectra confirmed complete polymerization, and thermogravimetric analyses demonstrated the stability of both the IIP and the non‐imprinted polymer (NIP). The IIP exhibited a higher surface area due to the formation of imprinted cavities. The optimal synthesis conditions were pH 7, 10 mg of the adsorbent, and a crosslinker‐to‐monomer molar ratio of 30. The IIP achieved an adsorption capacity of 5.07 mg g −1 for Pb 2+ , compared to 0.61 mg g −1 for the NIP, resulting in an imprinting factor of 341.16. Kinetic analysis followed a pseudo‐second‐order model, while isotherm fitting corresponded to the Langmuir model. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The IIP exhibited high selectivity for Pb 2+ over Cd 2+ , Fe 2+ , Cu 2+ , and Zn 2+ , with relative selectivity coefficients ranging from 3.04 to 10.06. Reusability tests confirmed its stability after five cycles, and recovery from real river water samples was close to 100%, demonstrating its effectiveness in the selective removal of Pb 2+ .