Synthesis Pb(II)-ion imprinted polymer using tannins from mango leaves (Mangifera indica L.)

This work reports the synthesis of Pb(II)-Ion Imprinted Polymer (Pb-IIP) using tannin extract from Mango leaf (Mangifera Indica L.) as functional ligand (chelating agent and monomer). Pb²⁺ ion found to form a stable compound at 1:1 complex with tannin in aqueous solution. The resulting complex of Pb²⁺ and tannin extract was polymerized using phenol-formaldehyde as cross-linker in acidic medium. The structure and properties of Pb-IIP were compared to Pb-IIP gallic acid and Non Imprinted Polymer (NIP) that were synthesized with similar conditions. These polymers were charaterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX). The template of Pb(II) ion was completely removed from the polymeric matrix using 1 mol/L HNO₃. The optimum pH of maximum sorption was 5 on IIP-tannin and IIP-gallic acid at 120 mins contact time. Maximum capacity of tannin Pb-IIP, gallic acid Pb-IIP, and NIP were 153.159 mg/g, 147.959 mg/g, and 138.218 mg/g, respectively. It was found that the tannin Pb-IIP sorbent is more selective than gallic acid Pb-IIP and NIP.