| Water contamination caused by metal ions is more and more serious and extensive because of global industrialization. Effective removal of toxic heavy metals by appropriate treatment technologies is a crucial issue for a long time. Among the heavy metals, copper is not acutely toxic to humans. But its extensive use and increasing levels in the environment may cause serious health problems. So it was enrolled in the 13 toxic metal species on the EPA's priority pollutant list. The conventional methods of removal Cu2+ from wastewater are chemical precipitation, ion exchange, electrolysis, reverse osmosis processes and adsorption on activated carbon. But these methods are industrially applicable for non-preferential separation. The inherent lack of selectivity is a major drawback. Therefore, in order to remove or separate a specific metal ion from a mixture, a selective separation method is required.Ion imprinted polymer were concerned greatly by environmental scientists because of its large adsorption capacity, high adsorption selectivity and mechanical strength, good performace of its re-use. Adsorption of different types of metal ion imprinted polymer had been reported, but the adsorption capacity and adsorption selectivity are still not very high, still needing to research and develop new imprinted adsorbent material.In this paper, the Cu2+ ion imprinted polymer (Cu2+-IIP) was prepared in the homogeneous phase by ion imprinted technology, being able to selectively remove Cu2+ from heavy metal waster. Polyethyleneimine was used as the basic bone which had functional groups to coordinate with template Cu2+ ion and the 1, 2-bibromoethane was used as crosslinker and the condition of synthesis was optimized. DMSO was selected as solvent, high-temperature cross-linking temperature to be 120℃,the best reaction time 24h.The chemical structure and surface morphology of the imprinted polymer were characterized by FTIR and SEM. The reasults suggest that the characteristic absorption peak of chemical structure agreed with the infrared spectroscopy and the surface of imprinted adsorbent prepared by ion imprinted method, had much more uniform loosen micropore and the pore structure was more orderly, compared with non-ion imprinted polumer.Static adsorption studies of Cu2+-IIP and Non-IIP were performed containting the effect of pH, adsorption kinetics, adsorption isotherm, adsorption selectivity. At pH=6, the maximum adsorption capacity of Cu2+-IIP was 83.3mg/g, about 2.4 times that of non-imprinted polymer (Non-IIP). It was a rapid adsorption kinetic, about 60 minutues to reach equilibrium. The adsorption progress was simulated by pseudo first-order and pseudo second-order kinetic model, suggesting that can be better simulated bysecond-order kinetic model. The linear correlation coefficient was 0.99446, indicating to be chamical adsorption progress. The sorption data was analyzed by Langmuir and Freundlich isotherm models.The reasults showed that it was close to Langmuir model, belonging to monolayear adsorption. Adsorption were performed at different temperatures, founding the higher temperature, the lower adsorption capacity. It may be exothermic reaction. Additionally, Cu2+-IIP performed good adsorption selectivity towards Cu2+ with the interference of Ni2+, Zn2+ or Pb2+, completely for the aim of selective enrichment and separation. The reusability of Cu2+-IIP is better and the fifth adsorption capacity still reach 95.21% of the original. In all, these results indicated that Cu2+-IIP have a significant imprinting effect and good reusability, to be a promising absorbent for real wastewater treatment for its potential economic value. |
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