Separation of Re(VII) from aqueous solution by acetone-enhanced photoreduction: an insight into the role of acetone

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 380; p. 111823
• Main Authors: Wang, Yi, Wu, Zhihao, Weng, Hanqin, Ding, Xuchen, Wang, Lan, Li, Fuhai, Wei, Yaxiong, Cheng, Sheng, Yamashita, Shinichi, Lin, Mingzhang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2019
• Subjects: Acetone; Photoreduction; Rhenium; Separation; Technetium; Photoreduction; Technetium; Separation; Rhenium; Acetone
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2019.04.034

[Display omitted] •An acetone-enhanced photoreduction method was adopted to separate ReO4−.•The mechanism of enhanced photoreduction by acetone was proposed.•The efficient separation (separation ratio > 95.2%) of Re was achieved within 30 min.•The selective photoreduction separation of Re(VII) / Nd(III) was realized. Efficient separation of rhenium (Re) from aqueous solution is pivotal in the resource recovery, and suitable to simulate the elimination of radiotoxic technetium (Tc) due to their similar properties. In this work, we achieved a high Re(VII) separation ratio of 95.2% within 30 min from aqueous solution via an acetone-enhanced photoreduction method, in which soluble ReO4− was reduced to insoluble ReOx and Re(0) in the presence of acetone and isopropanol. Compared with the situation in absence of acetone, acetone absorbed most of the UV energy, and the produced triplet acetone could abstract Hα atoms from isopropanol to form more strongly reductive ketyl radicals, leading to the enhancement in photoreduction. Isopropanol was the most qualified for Re(VII) photoredction due to its low C–Hα bond energy. The addition of alkali also benefited the Re(VII) separation by eliminating produced protons, and stabilizing the intermediate Re(VI) to preventing the re-formation of Re(VII) through disproportionation of Re(VI). Furthermore, selective and effective separation of Re(VII) from simulated high level liquid waste containg Nd(III) was realized as well. This work gains an insight into the role of acetone in the enhanced Re(VII) photoreduction, which may be of great significance in developing novel approaches for hydrometallurgy and spent nuclear fuel reprocessing.