Observation of silica nanoparticle growth in saline geothermal brine from the Yamagawa geothermal power station, Japan, using dynamic light scattering

Abstract Silica nanoparticle growth during the polymerization of silicic acid in saline geothermal brine from the Yamagawa geothermal power station, Japan, was examined using dynamic light scattering (DLS). Two types of polysilicic acid particles (large and small) were found to grow simultaneously after vapor–brine separation at the surface. The DLS results seemed to indicate that the average particle size increased over the initial 70 min and then decreased, however this is most likely due to the larger particles settling out. The small particles gradually increased to 200 nm over 180 min. As deduced from the change in the numbers of the two types of polysilicic acid particles, the small particles were absorbed by the large particles.