Abstract: The layer-by-layer electrostatic assembly process and chemical cross-linking technology were developed for Cu(Ⅱ) ion-imprinted composite membranes. Poly(acrylic acid) and polyethylenimine-copper(Ⅱ) ion complexes were assembled alternately on the surface of microporous polypropylene membrane (MPPM) by electrostatic action. Then the assembled layers were cross-linked by epichlorohydrin. The Cu(Ⅱ)-ion imprinted composite membranes obtained after the removal of Cu(Ⅱ) ions with acetic acid, characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and environmental scanning electron microscopy, show satisfactory hydrophilicity and stability. The composite membrane can take water up to 819 times that of MPPM. The mass of assembled layers can maintain more than 94% after oscillating washing in 1.5 mol·L^-1 NaCl solution or in 55℃ water for 48 h. The equilibrium adsorption experiments indicate that the ion-imprinted composite membranes exhibit high adsorption capability and high selectivity towards Cu(Ⅱ). The maximum adsorption capacity is 112.87 mg·cm^-2, and the selectivity coefficients are 17.72, 26.66, 17.43, 16.87, 29.72 and 19.75 with Pb(Ⅱ), Zn(Ⅱ), Ni(Ⅱ), Co(Ⅱ), Mg(Ⅱ) and Mn(Ⅱ) as competing ions, respectively. The adsorption thermodynamics and kinetics show that the adsorption process of Cu(Ⅱ) is in monolayer adsorption and is dominated by chemical interaction. The ion-imprinted composite membranes exhibit good regeneration ability, and their adsorption capacity can be maintained over 90% even after ten adsorption-desorption cycles.

Key words: layer-by-layer electrostatic assembly, ion imprinted, membrane, selectivity, separation, preparation, copper ion

摘要： 将聚丙烯酸和聚亚乙基亚胺-Cu（Ⅱ）络合物通过静电作用交替组装到聚丙烯微孔膜（MPPM）表面，再通过环氧氯丙烷的交联，使组装层形成交联体系，洗脱除去Cu（Ⅱ）离子，制得Cu（Ⅱ）离子印迹复合膜。采用FTIR、XPS和ESEM对膜表面的化学组成及物理形态进行了表征。制得的离子印迹复合膜具有良好的亲水性和稳定性，吸水量能够达到MPPM的819倍以上；在1.5 mol·L^-1 的NaCl水溶液或55℃水浴中振荡洗涤48 h，膜表面的组装层质量能保持在94%以上。平衡吸附实验结果发现，离子印迹复合膜对Cu（Ⅱ）离子具有良好的吸附能力与高的选择性，饱和吸附量可达112.87 mg·cm^-2，以Pb（Ⅱ）、Zn（Ⅱ）、Ni（Ⅱ）、Co（Ⅱ）、Mg（Ⅱ）或Mn（Ⅱ）作为竞争离子，膜对Cu（Ⅱ）离子的选择性系数分别达17.72、26.66、17.43、16.87、29.72和19.75。吸附热力学与动力学研究结果表明，吸附属于单分子层吸附，吸附主要受化学作用控制。制得的离子印迹复合膜具有良好的再生能力，10次吸附-脱附循环后，对Cu（Ⅱ）离子的吸附量能保持在90%以上。

关键词: 层层静电组装, 离子印迹, 膜, 选择性, 分离, 制备, 铜离子