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

Rodriguez-Gomez P.; Vega-Chacón J.; López R.; Florida N.; de Liss Meza Lopez F.; Sotomayor M.D.P.T.; Picasso G. · Polymer Engineering and Science (2025) · DOI: 10.1002/pen.70061

Resumen

This work focuses on the selective removal of low concentrations of Pb2+ using ion-imprinted polymers (IIPs). Dithizone was selected as the binding agent due to its strong affinity for Pb2+. 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 Pb2+, 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 Pb2+ over Cd2+, Fe2+, Cu2+, and Zn2+, 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 Pb2+.

Instituciones: Universidad Nacional de Ingeniería