Abstract
The work presented involved the fabrication and evaluation of an ion‐imprinted azo‐functionalized phenolic resin for selective extraction of Ni2+ ions from aqueous media.
The work presented involved the fabrication and evaluation of an ion‐imprinted azo‐functionalized phenolic resin for selective extraction of Ni2+ ions from aqueous media. The azo‐containing ligand was first synthesized by coupling of a p‐aminophenol diazonium salt with resorcinol. The ligand was coordinated with Ni2+ ion template before condensation polymerization with formaldehyde and resorcinol was performed. The Ni2+ ions were extracted from the crosslinked resin matrix to finally afford the Ni2+ ion‐imprinted Ni‐PARF adsorbent. The synthetic steps were extensively investigated using elemental analysis and Fourier transform infrared, NMR and energy‐dispersive X‐ray spectroscopies. Also, the surface morphologies along with the surface areas of the adsorbent resin were evaluated using scanning electron microscopy and Brunauer–Emmett–Teller techniques, respectively. Batch experiments indicated that the pseudo‐second‐order kinetic equation provided the best fit with the experimentally obtained kinetic data and equilibrium was reached after 40 min. The isotherm studies were also in a good fit with the Langmuir model and the maximum adsorption capacities of Ni2+ ions with respect to both Ni‐PARF and control non‐imprinted C‐PARF adsorbents were around 260 and 100 mg g−1, respectively. In the presence of Co2+, Cu2+, Zn2+ and Pb2+ as competing coexisting ions, the relative selectivity coefficients of Ni‐PARF for Ni2+ were, respectively, 84.91, 44.97, 30.41 and 32.20. Regeneration experiments indicated that after eight adsorption/desorption cycles, the Ni‐PARF adsorbent still maintained around 97% of its initial efficiency. © 2018 Society of Chemical Industry