A Size-Controllable Precipitation Method to Prepare CeO2 Nanoparticles in a Membrane Dispersion Microreactor

A membrane dispersion-based microreactor was used to prepare ceria nanoparticles using cerium nitrate and ammonia–water as the raw reagents. The traditional precipitation process makes it difficult to control crystal size in a stirred tank reactor; therefore, a new membrane dispersion microreactor was used, which was able to easily control the crystal size. Most importantly, the size of ceria nanoparticles was significantly reduced because of the enhanced mixing performance of the membrane dispersion microreactor. The crystal size of the prepared ceria in this new procedure reached 8.2 nm in comparison to ∼16.7 nm from the traditional precipitation process under identical conditions. The effects of supersaturation, pH value, mixing intensity, and reaction temperatures were also investigated in detail. Therefore, ceria nanoparticles with average sizes of 7–12 nm can be controllably obtained. Furthermore, the reaction time to reach 90% AO7 degradation rates was improved by ∼89.2% using the ceria prepared in...