Enhanced selectivity for the removal of Hg(II) ions from illegal gold mining by specific recognition site on a novel ion-imprinted polymer microparticles

The current study successfully synthesized a novel mercury ion imprinted polymer (IIP-Hg) microparticles using a precipitation polymerization approach. The synthesis involved 4-vinyl pyridine as the functional monomer and ligan complex, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, benzoyl peroxide (BPO) as the radical initiator, and ethanol as the green porogen. The adsorption performance of Hg(II) ions was investigated through batch and solid phase extraction methods. The optimization of adsorption conditions included variables such as pH, contact time, dosage, Hg(II) initial concentration, and temperature. The adsorption kinetics and isotherms were found to follow pseudo-second-order and Langmuir models, respectively. The result showed that IIP-Hg had an enhanced adsorption capacity (41.32 mg g −1 ) than the non-imprinted polymer (NIP) (23.31 mg g −1 ), with a high imprinting factor (α) of 1.77. The thermodynamic adsorption was spontaneous, exothermic, and increased randomness. The selectivity of IIP-Hg was evaluated to show good performance against other metal ions, including Cu(II), Pb (II), and Cd(II). Additionally, the IIP-Hg exhibited good removal of Hg(II). It removed 99.05 % (RSD = 0.56, n = 3) of Hg(II) effluent wastewater from illegal gold mining. The IIP-Hg also exhibited good reusability. The IIP-Hg has great potential for separation, preconcentration, and selective adsorption for Hg(II). • The IIP-Hg microparticles were successfully synthesized using the precipitation method using ethanol as a low-toxic porogen. • The IIP-Hg microparticles have a specific recognition site for Hg(II). • High selectivity and reusability of IIP-Hg microparticles for Hg(II) sorption. • The gold extraction wastewater used for the adsorption investigation process.