Production of starch nanoparticles through solvent-antisolvent precipitation in a spinning disc reactor

The spinning disc reactor (SDR) uses surface rotation to produce thin film flow with improved mixing and reduced residence times in chemical processing applications. Solvent-antisolvent precipitation is one such process that can benefit from these properties. This study investigates the film hydrodynamics and precipitation of starch nanoparticles by contacting starch dissolved in sodium hydroxide with ethanol as the antisolvent. One objective of this study is to understand how interactions of the disc surface topography (grooved and smooth) with other parameters such as liquid flowrate, antisolvent to solvent flow ratio and disc speed impact the mixing and precipitation processes. Results indicate that an increase in flow rate and rotational speed leads to smaller nano-particles and narrower size distributions, which is attributed to increased shear and instabilities within the liquid film. It was also observed that an increased antisolvent to solvent ratio caused a reduction in particle size, as increased antisolvent generated higher supersaturation. Results showed that although particle size was not significantly influenced by the disc texture, the size distribution was narrower and higher yields were obtained with the grooved disc surface. The grooved disc therefore offers the opportunity for higher throughput in the solvent-antisolvent precipitation of starch particles with better product quality.