Low-angle-dependent [e-mail].2 photonic crystal hydrogel material for visual detection and removal of uranyl ions

• Published in: Mikrochimica acta (1966) 2020-08, Vol.187 (8)
• Main Authors: Shi, Wenhui, Cheng, Meifang, Chen, Qianshan, Wang, Shihong, Zhou, Jun, Wu, Zhaoyang
• Format: Article
• Language: English
• Subjects: Acrylic acid
• ISSN: 0026-3672
• DOI: 10.1007/s00604-020-04456-8

A low-angle-dependent photonic crystal hydrogel (LAD-PCH) material was developed to simultaneously detect and remove uranyl ions (UO.sub.2.sup.2+). Different from traditional SiO.sub.2 photonic crystal hydrogel with the problem of angle dependency, the LAD-PCH material overcomes the restriction of observation direction. The LAD-PCH is a composite material with the photonic crystal array of 180-nm monodisperse [e-mail].2 particles embedded into the functional hydrogel. As one UO.sub.2.sup.2+ can bind to multiple carboxyl groups and amide groups, the functional hydrogel fabricated by acrylic acid and acrylamide will shrink after chelating. These changes in the hydrogel volume alter the array spacing and trigger a blue shift of diffraction wavelength and naked-eye visual color changes of LAD-PCH. The color can vary from orange-red to orange, yellow, green, and cyan, corresponding to the determination range of 100 pM-100 [mu]M. The LAD-PCH material detects UO.sub.2.sup.2+ sensitively as the lowest detectable concentration is about 100 pM, and removes UO.sub.2.sup.2+ high-efficiently as the maximum adsorption capacity of U(VI) is about 1010 mg g.sup.-1 at 298 K. This LAD-PCH material is convenient and has potential to simultaneously monitor and remove UO.sub.2.sup.2+ from uranium-polluted water.