Kinetic model of heterogeneous growth onto organic particles in supersaturated water environments

Abstract

Submicrometer organic particulate matter (PM2.5) is a significant pollutant in industrial environments that poses a severe threat to the product quality and physical wellbeing of production personnel. Water vapor phase transition is a particle growth mechanism through the nucleation of organic particles by a supersaturated steam field and the formation of droplet embryos in the active part of the particle surface, which promotes the growth of organic particles and reduces the suspended concentration of organic particles in the plant environment. This study establishes a kinetic model for the heterogeneous nucleation of submicrometer organic matter particles under water vapor conditions. Considering the particle surface roughness, condensation mechanism, and three-phase line long-force correction, the model introduces a correction of the orientation force of the droplet embryo on the surface of the organic particles. Using polyalphaolefin as a representative organic particle, this study investigated the influence of condensation mechanisms on the radius of droplet embryos, the effect of the saturation ratio on the radius of the droplet embryo, and variations in the nucleation barrier and nucleation rate. The results indicate that the kinetic model of organic particulate matter modified with orientation force exhibits a higher rate of liquid droplet embryo formation than conventional particle kinetic models. Furthermore, as the saturation ratio increases, the critical nucleation free energy decreases, rendering the nucleation barrier easier to overcome. A negative correlation exists between the nucleation rate and nucleation barrier, with an optimal value for the saturation ratio.