锂的两种同位素⁶Li和⁷Li均是核能领域重要的基础原料。本文提出将具有同位素分离效应的冠醚与聚砜接枝，并采用相转化法制备聚合物多孔膜，构建填充膜色谱考察锂同位素分离效应。 首先通过氯甲基化聚砜(CMPSf)和4'-氨基苯并15-冠-5(AB15C5)间亲核取代和交联反应将AB15C5固载于聚合物上，以液固萃取方式考察聚合物锂同位素吸附分离性能。结果表明，随阴离子软度增大、冠醚固载量增加、溶剂极性减小以及萃取温度的降低，聚合物锂离子吸附过程分配系数增加。其中，最大锂同位素分离因子(α)高达1.029，且发现⁶Li⁺富集于含冠醚的聚合物相中。 提出原位一锅法(反应控制-相转化法)亦即依据CMPSf和AB15C5反应进程并以其为铸膜液制备PSf-g-AB15C5多孔膜。结果发现，随反应时间延长及反应液粘度增加，铸膜液相转化过程双扩散速率变缓，膜断面逐渐呈现海绵状结构。当CMPSf取代度为32％，反应温度为45 ℃时，聚合物膜最大冠醚固载量为0.524 mmol／g。以30wt％的乙醇／水溶液为凝固浴，温度为40 ℃时，制备的多孔膜通量达到1936 L／㎡·h。采用动态循环吸附法考察多孔膜对锂同位素吸附分离规律。 PSf-g-AB15C5膜吸附平衡时间为30 min，吸附量为0.44 ㎎／g，远高于静态吸附量(0.043 ㎎／g)。膜对锂离子吸附行为符合Freundlich吸附模型和准一级吸附模型，即表现为焓驱动自发进行的物理吸附行为。多孔膜最大α为1.055，满足工业应用所要求的最低值1.03。DFT计算结果表明，PSf-g-AB15C5中冠醚与⁶Li⁺形成络合物结构能量更低，络合作用较强，即更易于富集⁶Li⁺，与实验结果一致。 以钛片为阳极，不锈钢网为阴极，考察电场驱动下PSf-g-AB15C5膜锂同位素分离性能。结果发现，锂离子跨膜渗透系数随离子浓度和电压增加而增大，随冠醚固载量增大而增加，随聚合膜层数增加而减小，其最优离子渗透系数为10.97 m／s。电场作用下膜α从1.027减至1.018，说明电场有利于促进膜吸附分离作用。 根据同位素分离的级联理论，以PSf-g-AB15C5多孔膜(厚度0.1 ㎜)为膜芯，采用层层叠加法构建80层膜色谱柱。以10 mL LiI(1g／L)为锂源，淋洗法考察锂同位素分离性能。结果表明，膜色谱吸附过程不存在粒子内扩散，传质阻力较小。在操作压力0.18 MPa下，色谱柱流速高达18 mL／h。⁷Li⁺富集在淋洗液前端，⁷Li⁺富集在淋洗液后端。经四级分离后，⁷Li⁺丰度由92.4％提高至92.66％， ⁶Li⁺丰度由7.6％提高至7.8％。同时，以氮气为载气驱动膜色谱分离时，经过七级分离⁷Li⁺丰度提升至92.68％，表现出更好的锂同位素分离性能。 关键词：4'-氨基苯并-15-冠-5接枝聚砜；锂同位素分离；原位一锅成膜法；多孔膜；多级膜色谱

 In nuclear industry, Lithium isotopes ( ⁶Li and ⁷Li) are one of the prime important materials. In this work, a crown ether (4'-aminobenzo-15-crown-5-ether (AB15C5)) with the great potential for efficient lithium isotopes separation was grafted onto chloromethylated polysulfone (CMPSf) to prepare PSf-g-AB15C5, which was used to fabricate microporous membrane via nonsolvent induce phase separation (NIPS). Then the membrane-based chromatography was designed for lithium isotope separation. At first, AB15C5 was graft onto CMPSf via nucleophilic substitution reaction and crosslink reaction. The obtained polymers were used for lithium isotope separation by solid-liquid extraction. Results showed that the distribution coefficient (K〓) increased with an increase in the immobilization amount (I〓) of crown ether, and decreased with the increase of the polarity of solvent and extraction temperature. The highest equilibrium separation factor of lithium isotope (α) obtained from PSf-g-AB15C5 polymer was 1.029. Meanwhile, it was found that ⁶Li⁺ was enriched in the crown ether phase. The reaction system between of CMPSf and AB15C5 as casting solution at a certain time was employed to fabricate PSf-g-AB15C5 porous membranes via in situ one-pot reaction-phase separation method. Results showed that the viscosity of reaction solution increased with the time of nucleophilic substitution reaction and crosslink reaction. The casting solution with a high viscosity resulted in the delayed demixing and the formation of membrane with complete sponge-like structure. The maximum I〓 of crown obtained under the degree of substitution of CMPSf 32%, the reaction temperature 45 ℃. The pure water flux of the membrane obtained from 30wt% ethanol solution as coagulation as 40℃ was up to 1936 L/㎡·h. A dynamic adsorption method was employed to determine the performance of lithium isotope adsorptive separation by the PSf-g-AB15C5 membrane. It was found that the adsorption equilibrium was attained within 30 min. The absorption capacity was up to 0.44 ㎎/g, which was higher than that obtained from static adsorption (0.043㎎/g). Furthermore, it was observed that the adsorption process of Li⁺ onto membrane fits better with the Freundlich model and pseudo-first-order kinetic model, which means that it was an enthalpy-driven complexation and spontaneous adsorption process. The highest a obtained from the performance of the membrane was up to 1.055, which was much higher than the acceptable industrial scale separation factor (1.03). From the density functional theory (DFT) calculation, the complexes of crown ether with ⁶Li⁺ showed lower energy and stronger interaction, implying that ⁶Li⁺would enriched in the crown ether phase. Moreover, the electric field was used to investigate lithium isotope separation performance of the PSf-g-AB15C5 porous membranes in a cell. The membrane was fixed between the titanium sheet electrode which was the anode and stainless steel nets electrode (the cathode). In this experiment, it was learnt that the Li⁺ dialysis coefficient increased with an increase in the Li⁺ concentration, voltage, I〓 of crown ether and decreased with membrane layers. The optimal dialysis coefficient of Li⁺ was 10.97 m/s. It was also found that a of the PSf-g-AB15C5 membrane for lithium isotope separation under the electric field decreased from 1.027 to 1.018. This was an indicated indication that the field would promote the lithium isotope separation. Membrane chromatographic column with 80 layer of PSf-g-AB15C5 membranes (thickness 0.1 ㎜) was fabricated according to the cascade theory of isotopes separation. Elution chromatography method was employed to investigate the lithium isotope separation performance of the membrane chromatography with 10 mL LiI (1 g/L) as the source of lithium. Results showed that the membrane chromatographic column without intraparticle diffusion behavior exhibited a very low mass transfer resistance of membrane adsorption. The flow rate of membrane chromatographic column was up to 18 mL/h at the transmembrane pressure of 0.18MPa, which was much higher than that of resin-based chromatographic column (0.5-6 mL/h). It was found that ⁷Li⁺ was enriched in the solution phase in the region of the front band, whereas ⁶Li⁺ was left at the end of the band during the lithium isotope separation process. Further, the relative abundance of ⁷Li⁺ increased to 92.66%, and the relative abundance of ⁶Li⁺ increased to 7.8% after 4-stage separation by the column with 80 layers of membrane. Specifically, the relative abundance of ⁷Li⁺ increased to 92.68% after 7-stage separation with the N₂ as driving force. Keywords: 4'-aminobenzo-15-crown-5-ether; Lithium isotope separation; In situ onepot method; Porous membrane; Tandem membrane chromatography