印迹壳聚糖吸附剂对镍离子的选择性吸附行为研究

Investigation of nickel ion selective adsorption in solution using imprinted chitosan adsorbent amidst a high concentration of metal ions

为了有效分离软锰矿浸出液的镍离子,研究采用离子印迹技术,以壳聚糖为基体,制备了镍印迹壳聚糖珠体(Ni2+-imprinted Chitosan Beads, Ni-CTS)。采用傅里叶变换红外光谱(Fourier Transform Infrared Spectroscopy, FT-IR)对Ni-CTS进行了表征,考察了不同锰离子质量浓度背景及实际软锰矿浸出液中Ni-CTS对镍离子的选择性分离效果,以乙二胺四乙酸二钠(Ethylene Diamine Tetra-acetic Acid, EDTA)为解吸液对吸附剂的再生性能进行了研究。试验结果显示:在高质量浓度锰离子背景下,Ni-CTS对镍离子显示了较高的选择性,且先被吸附的锰离子会被后面吸附的镍离子取代,在Ni-CTS上存在对镍离子特异性吸附的活性位点。经过5次再生试验后,Ni-CTS对镍离子吸附质量比约为12.1 mg/g,仍表现出良好的吸附性能。在实际软锰矿浸出液中,吸附反应后浸出液中的锰镍质量浓度的比值由3 020提高到了8 635。

To efficiently separate nickel ions from pyrolusite leaching solution,we synthesized imprinted chitosan adsorbents known as(Ni 2+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 theρ(Mn)/ρ(Ni)equaled 3000,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 3020 to 8635.In summary,Ni CTS exhibited the ability to selectively remove nickel ions from the actual pyrolusite leaching solution.