羧基含氟聚合物纳米纤维膜的制备及对铜(II)的吸附性能

以甲基丙烯酸十二氟庚酯(DFHMA)和甲基丙烯酸(MAA)为单体,通过溶液聚合法制备出共聚物DFHMA-co-MAA,将DFHMA-co-MAA与聚偏氟乙烯(PVDF)按一定质量共混,采用静电纺丝方法,制备出羧基含氟聚合物(PVDF-DM)纳米纤维膜,用以吸附溶液中Cu(II)。讨论了PVDF和DFHMA-co-MAA的质量配比对纤维微观形貌和对Cu(II)吸附性能的影响,得出当PVDF与DFHMA-co-MAA的质量比为1∶2时,纤维的微观直径较均一且吸附性能最佳,故实验采用该质量配比制备PVDF-DM。使用红外光谱对PVDF-DM进行表征,显示出PVDF-DM纤维膜中含有—OH和C＝O等活性吸附基团。以PVDF-DM纳米纤维膜为吸附剂,探讨了吸附剂用量、吸附pH值和吸附时间对Cu(II)吸附性能的影响,并研究了吸附过程的动力学模型。结果表明,室温下,当吸附剂用量为0.03g,pH=5时,吸附60min达到吸附平衡,吸附率和吸附量分别为94.37%和62.91mg/g,PVDF-DM纳米纤维膜对Cu(II)的吸附过程同时满足拟一级动力学和拟二级动力学模型,说明该吸附过程包含了化学吸附和物理吸附。PVDF-DM纳米纤维膜循环使用5次后,吸附能力仅降低16.23%,说明PVDF-DM纳米纤维膜具有很好的再生使用能力。

Preparation of carboxyl fluorine-containing polymer nanofibermembrane and its adsorption performance for copper(II)

The copolymer (DFHMA-co-MAA) was prepared by solution polymerization method with dodecafluoroheptyl methacrylate-co-methacrylic acid (DFHMA) and methacrylic acid (MAA) as the monomers. Then DFHMA-co-MAA was blended with polyvinylidene fluoride (PVDF) at certain mass ratio. The carboxyl fluorine-containing ploymer (PVDF-DM) nanofiber membrane was prepared via electrospinning for the adsorption of Cu(II) in the solution. The effect of mass ratio of PVDF and DFHMA-co-MAA on the micro morphology and the adsorption property for Cu(II) of nanofiber membrane was investigated. The results showed that the diameters of PVDF-DM nanofiber membrane were uniformity and the adsorption performance for Cu(II) was the optimum when the mass ratio of PVDF and DFHMA-co-MAA was 1∶2. Therefore, this mass ratio was adopted for the preparation of PVDF-DM. The PVDF-DM nanofiber membrane was characterized by infrared spectroscopy. It was found that the PVDF-DM nanofiber membrane contained some active adsorption group such as —OH and C＝O. The effect of adsorbent dosage, adsorption pH and adsorption time on the adsorption property for Cu(II) by PVDF-DM nanofiber membrane was investigated. Moreover, the kinetic model of this adsorption process was also inveatigated. The results indicated that the adsorption equilibrium was reached at 60min at room temperature when the adsorbent dosage was 0.03g at pH=5. The adsorption rate and adsorption capacity was 94.37% and 62.91mg/g, respectively. The adsorption behavior for Cu(II) by PVDF-DM nanofiber membrane could be described by both pseudo-first-order kinetic model and pseudo-second-order kinetic model, indicating that this adsorption process included both chemical adsorption and physical adsorption. The adsorption ability of PVDF-DM nanofiber membrane for Cu(II) was only decreased by 16.23% after recycling for 5times. In other words, the prepared PVDF-DM nanofiber membrane had good regeneration property.