Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, China; College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.
Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, China; College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China; Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, China.
J Colloid Interface Sci. 2022 Mar 15;610:1015-1026. doi: 10.1016/j.jcis.2021.11.152. Epub 2021 Nov 26.
Polyacrylonitrile (PAN)-based materials have been studied for decades as uranium (U(VI)) adsorbents, because the further products of abundant nitrile groups, amidoxime (AO) groups, show great affinity for U(VI) ions. However, excessive amidoximation could cause the shrinkage of PAN fibers, resulting in decreased adsorption performance. Hence, an amino-reinforced amidoxime (ARAO) swelling layer was constructed on the PAN fiber surface (PAN-NH-AO) by modification of the strongly hydrophilic amino group to prevent shrinkage. The molecular chains in the ARAO swelling layer would be swelled due to the adsorption of a large amount of water. Simultaneously, U(Ⅵ) ions can penetrate into the ARAO swelling layer with water molecules and coordinate with amino or AO groups, leading to increased adsorption performance. PAN-NH-AO exhibited maximum U(VI) and water adsorption capacities of 492.61 mg g and 20.32 g g at 25 ℃ with a swelling ratio of 20.73%, respectively. The adsorption capacity of PAN-NH-AO was 0.312 mg g after a 91-day immersion in Yellow Sea, China. The study of the adsorption thermodynamics and kinetics of PAN-NH-AO showed that the adsorption process was spontaneous homogeneous chemical adsorption. This paper proposes a novel method to obstruct amidoximation induced shrinkage and to maximize the potential application of PAN-based materials.
聚丙烯腈 (PAN) 基材料作为铀 (U(VI)) 吸附剂已被研究了几十年，因为丰富的腈基进一步产物，偕胺肟 (AO) 基团，对 U(VI) 离子表现出极大的亲和力。然而，过度的偕胺肟化会导致 PAN 纤维收缩，从而降低吸附性能。因此，通过修饰强亲水性氨基来构建在 PAN 纤维表面的氨基增强偕胺肟 (ARAO) 溶胀层（PAN-NH-AO），以防止收缩。由于大量水分子的吸附，ARAO 溶胀层中的分子链会溶胀。同时，U(Ⅵ) 离子可以与水分子一起穿透到 ARAO 溶胀层中，并与氨基或 AO 基团配位，从而提高吸附性能。在 25°C 下，PAN-NH-AO 的最大 U(VI) 和水吸附容量分别为 492.61mg g 和 20.32g g，溶胀比为 20.73%。PAN-NH-AO 在我国黄海浸泡 91 天后的吸附量为 0.312mg g。对 PAN-NH-AO 的吸附热力学和动力学研究表明，吸附过程是自发的均相化学吸附。本文提出了一种阻止偕胺肟化诱导收缩并最大限度地发挥 PAN 基材料应用潜力的新方法。
