期刊名：Colloids and Surfaces, A. Physicochemical and Engineering Aspects
题目：A general theory for describing coagulation kinetics of variably charged nanoparticles
作者：Zhu, Longhui；Tian, Rui；Liu, Xinmin；Xiong, Hailing；Li, Hang
摘要：Theoretically, many factors will influence the coagulation kinetics of variably charged nanoparticles, e.g. solution temperature, electrolyte concentration, pH, particle size, surface charge density, and van der Waals interaction force among particles etc. Unfortunately, at present there is not a theory could establish a mathematic relationship between the coagulation rate and the above mentioned factors. In this study, firstly we established a theory for describing the coagulation kinetics, and then the coagulation rates of variably charged hematite colloidal particles measured by laser light scattering under different pH conditions were employed to verify the established theory. The results showed that, by employing the pH dependent activation energy of variably charged particle's coagulation, we successfully established the theory to describe the coagulation kinetics of variably charged nanoparticles under different pH conditions; and the established theory has been well approved by the experiments. The established theory quantitatively show how the solution conditions of temperature, pH and electrolyte concentration, and how the particle natures of surface area per particle, point of zero charge (PZC) and van der Waals interaction force influence the coagulation rate of variably charged particles. Based on the established equation for describing hematite coagulation, we successfully predicted the coagulation rates change with pH for the hematite coagulation, and the predictions meet the experimental data very well. Besides, our study indicated that, the established theory suggested a new approach for the measurement of PZC of variably charge particle.
