聚丙烯酸-聚偏氟乙烯共混膜对Cu^2＋吸附特性的研究

应用热诱导聚合和相转移技术，制备了具有离子交换性能的聚丙烯酸-聚偏氟乙烯（PAA—PVDF）共混膜，采用XPS和SEM表征了PAA—PVDF共混膜的结构和组成，分析了PAA—PVDF共混膜对水溶液中Cu^2＋的吸附性能，研究了共混膜对Cu^2＋的吸附热力学和吸附动力学．结果表明，动力学吸附过程符合准二级动力学方程，等温吸附过程符合Langmuir模型．吸附过程的平均吸附能为8—16kJ／mol，表明该吸附过程为离子交换反应．热力学参数△G^0〈0、△H^0〉0、△S^0〉0，证实了吸附过程为自发的吸热过程。PAA—PVDF共混膜经吸附／脱附4次循环后，对废水中Cu^2＋的吸附量大于0．025mg／cm^2，脱附率超过95％。PAA—PVDF共混膜具有优良的吸附／脱附性能，良好的稳定性和潜在的应用前号。

Adsorption Characteristics of Cu2+ onto the Poly Acrylic Acid-Polyvinylidene Fluoride Blending Membrane

Using the combination method of thermally induced polymerization technique and phase inversion blending process, a novel poly acrylic acid- polyvinylidene fluoride （PAA- PVDF） blending membrane with ion- exchanging property, was prepared. The PAA - PVDF blending membrane was characterized by XPS and SEM. The adsorption property, the adsorption isotherm and the batch sorption kinetics of Cu2＋ by the PAA - PVDF blending membrane were studied, The results indicated that the adsorption processes for Cu2＋ are found to follow the pseudo - second - order kinetics equation, And the isotherm of adsorption of Cu2＋ by the blending membrane is good agreement with that of Langmuir isotherm model. The values of the mean free energies of the adsorption process are found to be between 8 to 16 kJ/mol, which shows that the adsorption mechanism of the PAA - PVDF blending membrane is an ion - exchange process. The value of △G^0〈0、△H^0〉0、△S^0〉0, which shows that the adsorption of the PAA - PVDF membrane is a spontaneous and endothermic process. The experimental data also show that the PAA - PVDF blending membrane possesses an excellent adsorption/desorption property, the adsorption capacity of Cu2＋ onto the blending mem- brane in the synthesized Cu2＋ solution is more than 0.025 mg/cm^2, and its desorption efficiency is still beyond to 95%, after four adsorption/desorption processes. It can be found that the PAA - PVDF blending membrane can be reused almost without any significant loss in the adsorption performance, PAA - PVDF blending membrane can be used for the recovery of metal traces and polishing of treated effluents containing heavy metals.