Coagulation rate coefficient in colloidal systems: A hybrid stochastic-deterministic theory

• Published in: Chemical engineering science 2021-03, Vol.232, p.116289, Article 116289
• Main Authors: Herrera-Ordonez, Jorge, Cuatecontzi, Magali, Carro, Shirley
• Format: Article
• Language: English
• Subjects: Coagulation rate coefficient; Collins-Kimball; Diffusion-reaction; Effectiveness factor; Smoluchowski; Stochastic-deterministic model
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2020.116289

[Display omitted] •Smoluchowski’s rate coefficient is not consistent at all with experimental data.•A stochastic and other deterministic approaches have issues as well.•A hybrid stochastic-deterministic model leads to more consistent results.•Coagulation effectiveness factor was introduced to modulate the sink effect.•Particle coagulation with and without concentration gradients, are complementary. The Smoluchowski’s coagulation rate coefficient (kc-S) has been used for decades notwithstanding its predictions are not always consistent with experimental data. In this work, kc-S and Herrera-Ordóñez (kc-HO) models, were modified and combined to obtain a hybrid equation kc-h for the rate coefficient of rapid coagulation. Modification of kc-S consisted in adapting the concepts of diffusion-reaction, such as effectiveness factor F, to the case of particle coagulation which is considered a pseudo-reaction. Unlike the deterministic and stochastic approaches, the hybrid model kc-h can fit experimental data for the effects of size and concentration of particles, on kc, using only one adjustable parameter value for all particle sizes. The higher predictability of kc-h suggests that their assumptions are more realistic. The behavior of F indicates that the fusion of relatively large particles is more effective than that of small particles to produce the sink effect.