Selective adsorption of CuSO4 from mixed sulfate solutions by Cu(II) ion-imprinted polymers containing salicylaldoximes, ammonium cations, and tertiary amino groups

• A novel copper(II) imprinted polymer that can separate CuSO4 from the mixed sulfate aqueous media has been synthesized.
• Salicylaldoxime is designed as polydentate ligand and anchored on the network of the imprinted polymer.
• The polymer can allow pH value equilibrium after Cu2 + has been absorbed in the solutions.

A polymerizable complex of copper(II) ion with unsaturated quaternary ammonium cation-modified salicylaldoxime ligand was prepared and used to synthesize a novel copper(II) ion imprinted polymers (Cu(II)-IIPs). Elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), and NMR spectroscopy confirmed the structures of the polymerizable complex and Cu(II)-IIPs. Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller surface area analysis (BET), and scanning electron microscopy (SEM) characterized physical properties and morphologies of synthesized metal complex and corresponding polymers. The effect of pH, contact time, and initial Cu2 + and SO42 − concentration on the simultaneous adsorption of Cu2 + and SO42 − ions of Cu(II)-IIPs were investigated. Cu(II)-IIPs showed high hydrophilicity and simultaneously rapid adsorption of Cu2 + and SO42 − from solution. Moreover, Cu(II)-IIPs displayed highest adsorption capacity in the pH range of 5.0–6.5, the separation factor (β) between Cu2 + with respect to Fe3 + was 1866, the equilibrium adsorption capacities for Cu2 + and SO42 − were almost the same and close to 0.13 mmol g− 1 at 25 °C. Stripping experiments revealed that 1.5 mol L− 1 H2SO4 was an effective eluent for desorbing copper (II) ions from Cu(II)-IIPs. In additional, Cu(II)-IIPs exhibited good recyclability and reusability for 5 cycles without deterioration of its selective ion-absorbing capacity.

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