Effects of electrolytes and suwannee river humic acid on the aggregation behavior of silicon nanoparticles

Abstract

Studies about the impact of the release of silicon nanomaterials to the environment and on human health by the microelectronics and biomedical devices industries are urgently needed. The aggregation kinetics of silicon NPs was investigated using dynamic light scattering (DLS) and electron microscope (EM) in the presence of Ca2+ and Suwannee River Humic Acid (SRHA). The reaction-controlled regime and diffusion-controlled regime can be observed in the absence as well as presence of SRHA, which is qualitatively consistent with the traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) model. The aggregation rates in the presence of SRHA were higher than that in the absence of SRHA at the same Ca2+ concentrations and the critical coagulation concentrations (CCC) decreased from 0.4 M to 0.1 M. The enhanced aggregation was attributed to bridging caused by Ca2+ and SRHA.