Study On Preparation And Properties Of Copper And Nickel Ion Imprinted Polymers

Heavy metal ions are serious harmful to the environment, for example it can cause pollution of water, soil and atmosphere, further harm to human health and survival. More and more heavy metal will be used in the industry in the future, Therefore, the heavy metal pollution problems need to be solved urgently. We have been exploring new methods and new ways to harness the heavy metal pollution. Now the discovery of molecular imprinting technique has found a new way for us to solve this kind of problem.Its superior specific selection performance can be applied to the separation and enrichment of heavy metal ions in the water body, and has broad prospects. This paper mainly involve the copper and nickel ion.Cu²⁺ and Ni²⁺ ion imprinted polymer were prepared by dispersion polymerization with copper and nickel ion as template,1-vinylimidazole as functional monomer, and polyvinyl alcohol ?PVA? as dispersant. The azobisisobutyronitrile ?AIBN? was used as initiator and toluene as porogen. The structure and morphology were characterized by Fourier transform infrared spectroscopy, ultraviolet spectrum and scanning electron microscope. And the preparation conditions were optimized, the best preparation conditions of two imprinted polymer were obtained;?1? Cu²⁺ ion imprinted polymer (Cu²⁺-IIP):CuSO4·5H2O, 1mmol; 1-vinylimidazole,5mmol; EGDMA,30mmo(the molar ratio of Cu²⁺/1-vinyl imidazole/EGDMA of is 1:5:30); toluene,12ml; AIBN,0.06g. ?2? Ni²⁺-ion imprinted polymer (Ni²⁺-IIP):Ni?NO3?2, lmmol; 1-vinylimidazole,4.0mmol, EGDMA,20mmol (the molar ratio of Ni²⁺1-vinylimidazole/EGDMA is 1:4:20); toluene, 10mL; AIBN,0.06g.The experiment investigated some conditions that affect the adsorption performance of Cu²⁺-IIP and Ni²⁺-IIP on Cu²⁺and Ni²⁺. The results showed that Cu²⁺-IIP has better adsorption performance at ph=6. With the increase of temperature, the adsorption capacity increases gradually. It showed that adsorption process of copper ion impring polymer was endothermic. The thermodynamics was studied through fit curve of 1gK to 1000/T. the entropy change ??S?, enthalpy ??H? and free energy change ??G? of Cu²⁺-IIP were obtained. The adsorption process of Cu²⁺-IIP to copper ions is spontaneously for the adsorption free energy less than zero. The study on the adsorption kinetics of Cu²⁺-IIP showed that it conforms to Lagergren pseudo-second-order kinetics dynamic model, Qmax is 89.37 mg/g and it is more closer to the experimental value 86.37 mg/g. the correlation coefficient R2 is 0.9917. Ni²⁺-IIP has the best adsorption performance at ph=5, it's adsorption process is endothermic; It conforms to Lagergren pseudo-second-order kinetics dynamic model for Qmax= 14.77 mg/g is close to the experimental value 11.56mg/gStatic adsorption experiment showed that the saturated adsorption capacity of Cu²⁺-IIP is 86.37mg/g. It took only 90 minutes to reach adsorption equilibrium, the absorption rate is fast. The coefficient of competitive of Co²⁺ Ni²⁺, Zn²⁺, and Cd²⁺ ion were 3.44,3.31,3.5,3.44 respectively. Adsorption process conforms to the Langmuir isotherm model, after reused five times,the adsorption of Cu²⁺-IIP is as high as 95.7%, and it can still reached 88.7% after use 7 times, showing the good chemical stability.The saturated adsorption capacity of Ni²⁺ -IIP is 11.56mg/g. The absorption rate is fast, it took only 90 minutes to reach adsorption equilibrium. The coefficient of competitive Ni²⁺ Zn²⁺, and Cd²⁺ ion was 4.37,6.93,7.46 respectively. Adsorption process conforms to the Langmuir isotherm model. After reused five times, the adsorption of Ni²⁺-IIP is as high as 87.2%, showing the good chemical stability.