A novel multi-templated Cu-Fe-Ni ion imprinted polymer for the selective and simultaneous removal of toxic metallic ions from wastewater

A novel multi-templated Cu-Fe-Ni ion imprinted powder was synthesized to demonstrate the selective and simultaneous removal of targeted ions; Cu(II), Fe(II) and Ni(II), employing molecular imprinting technology (MIT) via template (print ions) guided by bulk polymerization method reacting methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethylacrylate (EGDMA) as cross linking agent in the presence of the initiator azobisisobutyronitrile (AIBN); Cu(II), Fe(II) and Ni(II) ions as template ions, and 1,10-phenanthroline as the complexing agent. The template ions were exhaustively removed from the synthesized polymer by rigorous, optimal template removal method involving, periodically increasing solvent (HCl) concentration from 1.0 M to 10.0 M. The physical and chemical properties of the sorbents were investigated using Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM). Operational parameters including time, pH and sorbent dosage for the rebinding batch experiments were optimized and found to be 15 min, 7.5 and 666.7 mg/L respectively. The optimized conditions were then applied to evaluate the effectiveness of the prepared Cu-Fe-Ni IIP through the percentage recoveries of the bound targeted metal ions in the real samples in the presence of competative ions and complex matrices of waste and borehole water. For the wastewater and borehole water collected from Glen Valley Wastewater Treatemnet Plant and Extention Five, Gaborone, Botswana respectively. The percentage recoveries of the removed targeted ions from the spiked samples were: 92.14 ± 0.16% (R2 = 0.9997), 106.09 ± 0.17% (R2 = 0.9993) and 99.86 ± 0.04% (R2 = 0.9995) respectively. The selectivity of the Cu-Fe-Ni IIP, competitive sorption studies between the template ions and similar ions were also carried out. The synthesized sorbents showed good selectivity towards the targeted metal ion by removing 90% - 98% of the templated ions as compared to 58% - 62% of the competitive ions.