Reductive dissolution studies of CeO2 and simulated mixed oxide fuel of (Ce, U)O2 in nitric acid medium

Cleaning Nanoceria Particles by Diluted HNO3 with H2O2 Mixture (NPM) Solution at Different Temperatures

“…Also in the Ref. 19, it shows that the amount of ceria dissolved decreases as the temperature drops, nevertheless, a small amount of dissolution still occurred at 37 °C, which is the same as pointed out in this work that ceria can still dissolve even at 20 °C.…”

“…Obviously, without adding U(IV), the Ea for the HNO 3 dissolution of ceria should be much higher than 40 KJ mol − . 19 In our work, it is found that the NPM (containing 2% HNO 3 (0.3 M) and 10% H 2 O 2 ) at 80 °C can completely dissolve the ceria particles contaminated on the SiO 2 substrate either by B20 ceria particles in 4 min or by A90 ceria particles in 20 min. In order to compare the dissolution rate of ceria by NPM with that by HNO 3 in Ref.…”

“…The ceria dissolution reaction has been investigated by Um et al by using H 2 SO 4 , 18 and Dhamodharan et al by using HNO 3 and HNO 3 with a reductant agent U(IV). 19 The ceria dissolution process can be described by a shrinking core model, and it is reaction controlled instead of diffusion controlled. The Arrhenius equation is written as:…”

“…In order to compare the dissolution rate of ceria by NPM with that by HNO 3 in Ref. 19, a solution consisting of 5 M mol −1 HNO 3 and 10 wt% H 2 O 2, was used to dissolve the A90 ceria particles at 80 °C, and the obtained dissolution rate was 20-23 mg min −1 , higher than that in 5 M HNO 3 with reducing agent U(IV). It can be deduced that the Ea of the ceria dissolution by NPM should be lower than 40 KJ mol −1 .…”

Two decades of ceria nanoparticle research: structure, properties and emerging applications

“…The dissolution of ceria in nitric acid is controlled by chemical reaction and not by diffusion as the dissolution rate did not change with the mixing rate. 244…”