Photo-induced removal of uranium under air without external photocatalysts

Abstract

Photo-induced transformation of soluble U(VI) to insoluble U(IV) is an effective way for uranium extraction and removal. However, the photoreduction process needs to be conducted under the protection of inert...

Mechanism of the Visible-Light-Promoted C(sp3)–H Oxidation via Uranyl Photocatalysis

“…It was found that fatty alcohols can quench the excited-state uranyl and be oxidized to aldehydes or ketones under aerobic light conditions. , The HAT mechanism was proposed for the photocatalytic oxidation of fatty alcohols by uranyl based on a linear relationship between the quenching constant logKq and the BDE of the C–H bond . The 1 H NMR spectra and theoretical calculations indicated that the alkyl hydrogen atom from the alcohol reactant was extracted in the reaction, , which is also consistent with the previously reported EPR experiment that α-hydroxyalkyl radicals were captured in the reaction system. , Based on these studies, it is expected that the benzyl alcohols, despite being a relatively stable intermediate in Figure , will be quickly oxidized by a uranyl photocatalyst. The calculated BDE values of C–H and O–H bonds in Figure S1 also show that it is easier to extract benzyl hydrogen than hydroxyl hydrogen.…”

“…16,17 The HAT mechanism was proposed for the photocatalytic oxidation of fatty alcohols by uranyl based on a linear relationship between the quenching constant logKq and the BDE of the C−H bond. 87 The 1 H NMR spectra and theoretical calculations indicated that the alkyl hydrogen atom from the alcohol reactant was extracted in the reaction, 88,89 which is also consistent with the previously reported EPR experiment that α-hydroxyalkyl radicals were captured in the reaction system. 90,91 Based on these studies, it is expected that the benzyl alcohols, despite being a relatively stable intermediate in → Int 1−4) is more preferred kinetically due to a much lower energy barrier of the dehydration process.…”

Molten Salt Synthesis of Carbon Nitride Nanostructures at Different Temperatures for Extracting Uranium from Seawater

“…The H 2 O 2 finally reacts with UO 2 2+ and produces (UO 2 )­O 2 ·2H 2 O under open-air conditions. It is reported that the photoinduced generation of H 2 O 2 and the reaction between uranyl and H 2 O 2 are the essential processes in the open system. , The SUPER method has exhibited unexpected great performance in spiked seawater under natural sunlight illumination.…”

“…15 The results showed that CN 550 represented excellent ability of both adsorption capacity and photocatalytic activity. By applying the sunlight-driven photocatalysis-assisted extraction (SUPER) method, uranyl ions were adsorbed on the surface of CN 550 and deposited there as metastudtite ((UO 2 )O 2 35,36 The SUPER method has exhibited unexpected great performance in spiked seawater under natural sunlight illumination.…”

A fluorescent N-doped carbon dot-hydrogel composite for concurrent selective detection and local hot spot promoted adsorption of uranium(vi)

“…4 Radioactive uranium has penetrated into the environment and its detection under complex extreme conditions (acid, base, temperature, coexisting ions and radiation) remains a challenge. In addition to the detection of uranium, the adsorption extraction of uranium has also been performed using an ion pathway 5 and metal-nitrogen-carbon (Fe-N x -C) electrocatalyst technology, 6 photoinduced multi-effects including photocatalysis and photothermal effects, [7][8][9] and piezoelectric 10 and thermoelectric effect 11 assisted catalytic processes. However, these materials cannot meet all the merits demanded for concurrent UO 2 2+ detection and extraction for environmental monitoring and protection.…”