The aim of this research was to synthesize magnesium hydroxide nanoparticles, which were further calcined to form magnesium oxide, using a spinning disk reactor. Magnesium hydroxide was prepared by continuously pumping two aqueous solutions of MgCl 2 and NaOH, respectively, into the chamber of the reactor, where a liquid-liquid reaction took place to form Mg(OH) 2 . The effects of various operating variables, including the rotation speed, reactant concentration, and liquid flow rate of the reactants, on the size of magnesium hydroxide nanoparticles were investigated. The particle size of magnesium hydroxide increased as the flow rate increased, but remained quite constant as the reactant concentration varied. As far as size and uniformity were concerned, the best lamellar magnesium hydroxide particles were 50-80 nm in length and 10 nm in thickness. The particle morphology and size of magnesium oxide calcined from produced magnesium hydroxide were also analyzed. Polyhedral nanoparticles of 30-70 nm magnesium oxide were obtained by calcinating lamellar hydroxide.

A spinning disk reactor (SDR) operated in a continuous mode was adopted for producing silver nanoparticles, aiming at an increase in the production rate. Two protecting agents, i.e., poly(vinylpyrrolidone) (PVP) and hydroxypropylmethyl cellulose (HPMC), were tested, which have been proven to be effective in our previous work of recycle operation. Using PVP as protecting agent, the effects of the operating variables, including the rotation speed, the feeding rate, the dosage of protecting agent, and reactant concentration, on the particle size and yield of the silver product were investigated. The experiment was further conducted using HPMC as protecting agent to compare the experimental results between the two protecting agents. The use of PVP gave smaller silver nanoparticles; however, a higher yield was obtained by using HPMC. Although the yield of continuous operation was lower than that of recycle operation, the production rate was much higher for either protecting agent, providing a great potential for commercialization.

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