Uranyl ion, the most soluble toxic uranium species, is recognized as an important index for monitoring nuclear wastewater quality. The United States Environmental Protection Agency (US EPA) and the World Health Organization (WHO) prescribed 30 ppb as the allowable concentration of uranyl ion in drinking water. This paper reports on a nanohybrid material that can detect uranyl ions spectroscopically and act as a uranyl ion absorbent in an aqueous system. Compound 1, possessing a salicyladazine core and four acetic acid groups, was synthesized and the spectroscopic properties of its UO22+ complex were studied. Compound 1 had a strong blue emission when irradiated with UV light in the absence of UO22+ that was quenched in the presence of UO22+. According to the Job's plot, Compound 1 formed a 1:2 complex with UO22+. When immobilized onto mesoporous silica, a small dose (0.3 wt %) of this hybrid material could remove 96% of UO22+ from 1 mL of a 100-ppb UO22+ aqueous solution.
Keywords: UO22+; fluorescence; mesoporous silica; salicyladazine.