Synthesis of Ternary Complex-Based Ion Imprinted Polymer Sorbent for Selective Adsorption of Lead Ions

In this study, Pb2+ ion imprinted polymer particles were synthesized by preparing a ternary complex of lead imprinted ions with 4-(2-pyridilazo) resorcinol and 4-vinyl pyridine. Pb-IIPs as sorbents with ternary complexes between Pb2+, PAR, and 4-VP as template carrier molecules had not been previously reported. The ternary complex formed was then copolymerized with methacrylic acid as a functional monomer, Trimethylolpropane trimethacrylate as a crosslinking agent, methanol as porogen, and benzoyl peroxide as initiator. Polymerization was carried out by the thermal method. HNO3 5 M was used to remove the template ion by shaking the polymer for 24 h several times to obtain leached IIP particles (Pb-IIPs). Non-Imprinted Polymers (NIPs) as control were similarly prepared without imprinted ions. In this study, two types of NIPs were made including with and without the addition of PAR ligands (NIP and NIPP). All polymer particles were characterized by spectral (FTIR), thermal (TGA-DTG), morphology (SEM), and nitrogen adsorption studies (BET). The adsorption and selectivity studies for lead ions were carried out with Pb-IIP, NIPP, and NIP. The adsorption of 20 mg l(-1) of Pb2+ using 25 mg of polymer particles in pH 6 with an interaction time of 90 min. The maximum adsorption capacity of leached Pb-IIP was found to be 14.3 mg g(-1) which is higher than the NIPP and NIP. The Pb-IIPs displayed excellent selectivity against three common divalent ions Cu2+, Cd2+, and Zn2+ with selectivity coefficients of 19.98, 42.15, and 42.96, respectively, showing high anti-interfere ability. The precision for the method was determined by the percentage of relative standard deviation (RSD) to be 2.9% for five times the replication of the adsorption measurement. The spike and un-spike samples method was conducted to assess the accuracy of the Pb-IIP adsorption which shows a high percentage of recovery values ranging from 97-103%, indicating its accuracy.