Iranian Medicinal Plants Society Journal of Medicinal plants and By-products 2322-1399 15 6 2026 11 01 Green Synthesis of Ion-Imprinted Polymers from Oak Gall Extract for Selective Removal of Chromium (III) Ions 664 670 135326 10.22034/jmpb.2026.370712.2051 EN Jabbar Ibrahim Ghulam Zarkoosh Department of chemistry, SR.C., Islamic Azad University, Tehran, Iran Fereshteh Nematollahi Department of chemistry, SR.C., Islamic Azad University, Tehran, Iran Kambiz Larijani Department of chemistry, SR.C., Islamic Azad University, Tehran, Iran Journal Article 2025 09 14 This study presents a new and eco-friendly approach to water purification through the development of ion-imprinted polymers (IIPs) enhanced with gold nanoparticles, synthesized using the tannin-rich extract of oak galls (<em>Quercus infectoria</em>) as both a natural reducing and stabilizing agent. By integrating biologically derived components with nanostructured materials, the proposed method enables the selective recognition and efficient removal of chromium (III) ions from aqueous solutions, offering a sustainable alternative to conventional synthetic polymer adsorbents and contributing to the advancement of green chemistry–based water treatment technologies. Oak gall extract, rich in tannins, was obtained using the Soxhlet method with a 70% ethanol: acetone solvent mixture. The presence of tannins was verified using the Folin-Ciocalteu method. The extract was used to synthesize gold nanoparticles, which were then integrated into the polymer membrane matrix. Various analytical techniques, including FTIR, FESEM, UV, and XRD, were used to analyze the structural and surface characteristics of the composite material. Optimal removal efficiency was achieved at a chromium concentration of 25 ppm and a flow rate of 1 mL/min, resulting in a 93% removal rate. This method offers a promising green chemistry solution for water treatment, with significant potential to improve water quality and mitigate heavy metal contamination. https://jmpb.areeo.ac.ir/article_135326_4f042054821be421e97adf836510132a.pdf