不同直径改性PAN纳米纤维膜与Fe^(3+)的配位反应及其配合物对有机染料降解的催化性能

Coordination Kinetics of Fe^(3+)with Membranes Based on Modified PAN Nanofibers with Different Diameters, and Catalytic Effect of Their Complexes on Decomposition of Organic Dye

使用静电纺丝技术和偕胺肟反应制备了三种不同直径的改性聚丙烯腈(PAN)纳米纤维膜,然后将它们作为配体分别与Fe3+进行配位反应制备改性PAN纳米纤维膜铁配合物,重点研究了三种改性PAN纳米纤维膜与Fe3+配位反应的动力学特性及其温度和Fe3+初始浓度的影响.最后将其作为非均相Fenton反应催化剂应用于染料降解反应中,考察了改性PAN纳米纤维膜直径对其催化活性的影响.结果表明,在所涉及的温度和浓度范围内,改性PAN纳米纤维膜与Fe3+之间配位反应不仅符合Langmuir和Freundlich吸附等温式,而且可理想地使用Lagergren准二级动力学方程进行描述,反应速率常数随着Fe3+初始浓度的增加而逐渐降低.在相同反应条件下,较小直径的纤维膜更容易与Fe3+发生配位反应,且反应速率常数和Fe3+配合量均随着纤维直径的降低而增大.不同直径改性PAN纳米纤维膜铁配合物在暗态条件下对染料的氧化降解反应表现出很好的催化活性,且在辐射光下其催化活性得到加强.改性PAN纳米纤维膜铁配合物的催化作用受到纤维直径的显著影响,由中等直径纳米纤维构成的配合物表现出最高的催化活性.

Membranes produced from modified polyacrylonitrile （PAN） nanofibers with different diameters were prepared by electrospinning and amidoximation. They were then used as ligands to coordinate with Fe^3＋ for preparing modified PAN nano-fibrous membrane Fe complexes. The coordination kinetics of three modified PAN nano-fibrous membranes with Fe^3＋ were studied, and the effects of temperature and the Fe^3＋ initial concentration on the coordination kinetics were also examined. Finally, the catalytic activities of the three modified PAN nano-fibrous membrane Fe complexes were evaluated as heterogeneous Fenton catalysts in the degradation of an organic dye. The effect of fiber diameter on the catalytic activity of the complexes was investigated. The results indicated that within the observed temperature and concentration ranges, the equilibrium data for the coordination of Fe^3＋ with the modified PAN nano-fibrous membranes correlated with the Langmuir and Freundlich isotherm equations, but the coordination kinetics showed better agreement with the Lagergren second-order equation. Modified PAN nanofibrous membranes with small diameters showed higher Fe-coordinating capacities and reaction rate constants under the same conditions, indicating that they reacted with Fe3~ more easily than the others did. Better catalytic activities for dye degradation were found for the three modified PAN nanofibrous membrane Fe complexes in the dark, and these were further improved by light irradiation. The catalytic activities of the complexes were significantly affected by the nanofiber diameter. The complex prepared using a modified PAN nanofibrous membrane with fibers of an appropriate diameter exhibited the best catalytic activity.