Investigation of nickel ion selective adsorption in solution using imprinted chitosan adsorbent amidst a high concentration of metal ions
To efficiently separate nickel ions from pyrolusite leaching solution,we synthesized imprinted chitosan adsorbents known as(Ni2+-imprinted Chitosan Beads,Ni-CTS)utilizing ion imprinting technology.In the preparation process of Ni-CTS,epichlorohydrin served as the cross-linking agent,while nickel ions acted as the template ions.The characterization of the adsorbent was conducted using Fourier transform infrared spectroscopy(FT-IR).The study investigated the impact of initial metal ion concentration and contact time on the adsorption capacity in both sole nickel solution and a binary system[ρ(Mn)/ρ(Ni)=0～3000].Additionally,it delved into the competitive adsorption behavior between nickel and manganese ions on the Ni-CTS in the binary system.Furthermore,the study explored the effect of time on the removal efficiency of nickel ions from the pyrolusite leaching solution.In a single solution,the adsorption capacity of nickel ions on Ni-CTS was measured at 15.83 mg/g.In the binary system,specifically when the ρ(Mn)/ρ(Ni)equaled 3 000,the adsorption capacity of nickel ions on Ni-CTS remained high at 12.31 mg/g,showcasing the remarkable selectivity of Ni-CTS towards nickel ions.Moreover,the study observed that initially adsorbed manganese ions on Ni-CTS were displaced by subsequently adsorbed nickel ions from the solution.It was speculated that the displacement resulted from adjacent adsorption and repulsion.The kinetic data was best fitted with the pseudo-second order kinetics model,even in the presence of high manganese concentrations.Additionally,Fourier transform infrared results revealed that the hydroxy and amine groups were primarily bound to metal ions.The Ni-CTS adsorbent demonstrated outstanding regeneration performance using Ethylene Diamine Tetra-acetic Acid(EDTA)as a desorption solution.Even after five cycles,the adsorption capacity of nickel ions on Ni-CTS remained at 12.1 mg/g.Following the adsorption reaction,the ratio ofρ(Mn)/ρ(Ni)in the actual pyrolusite leaching solution increased from 3 020 to 8 635.In summary,Ni-CTS exhibited the ability to selectively remove nickel ions from the actual pyrolusite leaching solution.
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