Effect of fibre diameter on fabrication of modified PAN nanofibrous membranes and catalytic performance of their Fe complexes for dye degradation

Polyacrylonitrile nanofibrous membranes (n-PAN-FMs) with different fibre diameters were prepared using electrospinning process and modified with hydroxylamine hydrochloride. The modified n-PAN-FMs were further coordinated with Fe3+ ions to produce a series of the modified n-PAN-FMs Fe complexes, and the catalytic activity of which was investigated as the heterogeneous Fenton catalyst for the dye degradation. The effect of fibre diameter on modification and coordination of n-PAN-FMs as well as the catalytic activity of the resulting complexes was also examined. The results indicated that increasing fibre diameter proportionally enhanced the amidoximation degree of n-PAN-FMs. The modified n-PAN-FMs consisting of small fibre diameters easily coordinated with Fe3+ ions, especially at high temperature to form the complex with high Fe content at the same conditions. Besides, these complexes exhibited the catalytic performance for the dye degradation in the dark and under visible irradiation at a wide pH range. The complex with middle fibre diameter showed a stronger catalytic performance than the complexes with much bigger or smaller fibre diameter due mainly to its large specific surface area and the proper size pores among fibres as well as better water affinity.