A Study on the Degree of Amidoximation of Polyacrylonitrile Fibers and Its Effect on Their Capacity to Adsorb Uranyl Ions

• Published in: Industrial & engineering chemistry research 2015-04, Vol.54 (12), p.3101-3106
• Main Authors: Zhao, Huanhuan, Liu, Xiyan, Yu, Ming, Wang, Ziqiang, Zhang, Bowu, Ma, Hongjuan, Wang, Min, Li, Jingye
• Format: Article
• Language: English
• Subjects: Adsorption; chemical structure; Density; Diffusion layers; engineering; Fibers; Fourier transform infrared spectroscopy; Hydrogels; hydroxylamine; ions; Mechanical analysis; mechanical properties; Nitriles; polyacrylonitrile; Polyacrylonitriles; scanning electron microscopy; Surface chemistry
• ISSN: 0888-5885; 1520-5045; 1520-5045
• DOI: 10.1021/ie5045605

Amidoximation of polyacrylonitrile (PAN) fibers was studied by reacting them with hydroxylamine. The chemical structure, mechanical intensity, and morphologies of PAN and amidoximated PAN (AO-PAN) fibers were evaluated by Fourier transform infrared spectroscopy, tensile tests, dynamic mechanical analysis, and scanning electron microscopy, respectively. A higher degree of amidoximation resulted in a higher conversion ratio (CR) of the nitrile group and a higher density of the amidoxime group, while also reducing the mechanical intensity of the fibers. During amidoximation, a hydrogel layer formed on the fiber surface by bonding with H2O molecules, increasing the diameter of the AO-PAN fibers. The layer thickness increased as the CR of the AO-PAN fibers’ nitrile group was increased. The hydrogel layer decreased the adsorption capability by hindering the diffusion of uranyl ions to the interior of the AO-PAN fibers. Therefore, a CR of about 10.8% would provide an appropriate balance between the mechanical properties and the adsorption capability.