聚丙烯腈复合纳米纤维膜的制备及其对金属离子的吸附性能

Preparation of Polyacrylonitrile Composite Nanofiber Membrane and Its Adsorption Property for Metal Ions

以羧基化聚丙烯腈(CPAN)为原料,通过复合改性和接枝改性的方式,制备β-环糊精(β-CD)/CPAN-g-聚乙烯亚胺(PEI)复合纳米纤维膜,为体系引入亲水的β-CD和吸附性能优异的PEI。通过红外光谱仪、X射线衍射仪、万能材料试验机、场发射扫描电镜等仪器对复合纳米纤维膜进行结构及性能表征,使用等离子体发射光谱仪、X射线光电子能谱仪探究复合纳米纤维膜对Cd^(2+)和Pb^(2+)的吸附性能及吸附机理。结果表明:改性得到的β-CD/CPAN-g-PEI复合纳米纤维膜具有优异的吸附性能,同时保留了纤维膜原有的力学性能,其对Cd^(2+)和Pb^(2+)的最大吸附量分别为176.67 mg/g和240.83 mg/g,吸附过程符合拟二级动力学模型和Langmuir等温吸附模型,且循环使用5次后仍保持80%以上的吸附性能。

Using carboxyl modified polyacrylonitrile(CPAN)andβ-cyclodextrin(β-CD)as spinning raw materials,β-CD/CPAN composite nanofiber membrane was prepared by electrostatic spinning process,andβ-CD/CPAN-g-PEI composite nanofiber membrane was prepared by active modification of carboxyl groups on the fiber membrane with the grafting of polyethyleneimine(PEI).Through both compound modification and grafting modification,β-CD and PEI were introduced to the fiber membrane with the aim to enhance adsorption and mechanical property of the fiber membrane.The structure and performance of composite nanofiber membranes were characterized by infrared spectroscopy,X-ray diffraction,universal material testing machine,field emission scanning electron microscopy.The adsorption property and adsorption mechanism for Cd2+and Pb2+were investigated by using plasma emission spectrometer and X-ray photoelectron spectrometer.The results showed thatβ-CD was mixed in the fiber membrane,and PEI was successfully grafted onto the fiber membrane without causing the destruction of cyano radical and loss ofβ-CD.β-CD/CPAN-g-PEI composite nanofiber membrane exhibited excellent adsorption property for Cd2+and Pb2+,while retaining the original mechanical property.According to static adsorption experiments,the maximum adsorption capacities ofβ-CD/CPAN-g-PEI composite nanofiber membrane for Cd2+and Pb2+were 176.67 mg/g and 240.83 mg/g,respectively.The adsorption process ofβ-CD/CPAN-g-PEI composite nanofiber membrane conformed to the pseudo-second-order kinetic model and Langmuir isothermal adsorption model,indicating thatβ-CD/CPAN-g-PEI composite nanofiber membrane mainly exhibited single-layer chemical adsorption for Cd2+and Pb2+.Moreover,β-CD/CPAN-g-PEI composite nanofiber membrane had good reusability,and maintained more than 80%adsorption property for Cd2+and Pb2+after 5 cycles of use.