Synthesis of Barium Sulfate Nanoparticles Using a Spinning Disk Reactor: Effects of Supersaturation, Disk Rotation Speed, Free Ion Ratio, and Disk Diameter

The aim of this research was to synthesize barium sulfate nanoparticles using a spinning disk reactor. Barium sulfate was produced by continuously pumping two aqueous solutions of BaCl 2 and Na 2 SO 4, respectively, into the chamber of spinning disk reactor, where a liquid−liquid reaction took place to form BaSO 4 . The influences of various operating and design parameters such as the initial supersaturation, disk rotation speed, free ion ratio, and the disk diameter on the size of barium sulfate nanoparticles were carefully investigated. By varying the supersaturation and disk rotation speed, a broad range of particle size ranging from micrometer sizes down to nanoparticles smaller than 100 nm can be produced. Using high disk rotation speed and high initial supersaturation, crystals ∼38 nm in size were produced. It was found that the variation of free ion ratio has a significant influence on the obtained particle size. Moreover, at a constant supersaturation and disk rotation speed, precipitation experiments with the excess amount of barium or sulfate ions lead to smaller mean particle size compared to those prepared under stoichiometric conditions.