Aggregation of polydisperse soil colloidal particles: Dependence of Hamaker constant on particle size

Studying the soil column formation in soft soil improved by vacuum preloading via coupled scale‐up CFD‐DEM simulations

“…The value of Hamaker constant $$Ha$$ was varied from 2$$ \times $$10 –20 J to 6.5$$ \times $$10 –20 J to study the effects of soil particle cohesion on drainage. The simulated value of $$Ha$$ is determined based on previous research 37,41,42 and the comparison between our preliminary simulation and Deng's experimental results (detailed in Section 3).…”

“…37 In numerical modeling, this constant is often treated as a lumped parameter and determined empirically. 37 From previous research, García-García et al 41 summarized the Hamaker constant values for clay-water systems reported in the literature, that is, in the range of 2-6× 10 -20 J. Xu 42 obtained the Hamaker constant of colloidal soil particles in water (with diameters less than 1000 nm) based on the Deryaguin-Landau-Verwey-Overbeek (DLVO) theory, which is 1.86 × 10 -20 J. Dong et al 36,37 gave the value of glass beads with diameters of 100±4, 250±9, or 500±20 μm in different liquids, which was in the range of 1× 10 -22 -6.5× 10 -20 J. From our preliminary simulation, it is found when 𝐻𝑎 equals 6.5×10 -20 J, the solid volume concentrations of the formed soil column are in the range of 0.50-0.55 (see Figure 13B), which are comparable to the test result obtained by Deng et al 6 (fluid volume concentration 𝜀 𝑓 = 0.48,𝜀 𝑠 = 1-0.48 = 0.52).…”

“…From previous research, García‐García et al 41 . summarized the Hamaker constant values for clay–water systems reported in the literature, that is, in the range of 2–6$$ \times \;$$10 –20 J. Xu 42 obtained the Hamaker constant of colloidal soil particles in water (with diameters less than 1000 nm) based on the Deryaguin–Landau–Verwey–Overbeek (DLVO) theory, which is 1.86 × 10 –20 J. Dong et al 36,37 . gave the value of glass beads with diameters of 100$$ \pm $$4, 250$$ \pm $$9, or 500$$ \pm $$20 μm in different liquids, which was in the range of 1$$ \times \;$$10 –22 –6.5$$ \times \;$$10 –20 J.…”

Insight into Hofmeister effects on aggregation of 2:1 and 1:1 type clay minerals

“…According to the Derjaguin, Landau, Verwey, Overbeek (DLVO) theory, the stability of the colloidal suspension is determined by the relative magnitude of electrostatic repulsive forces and long‐range van der Waals attractive forces (Hiemenz, 1977; Verwey, 1947). Van der Waals attraction mainly depends on the nature of the colloidal particles (Bergström, 1997; Faure et al, 2011; Xu et al, 2015, 2020), while the electrostatic repulsion between colloidal particles is mainly related to the charge properties of the colloidal particles and the nature of the medium solution (He et al, 2007; Huangfu et al, 2013; Ishikawa et al, 2005; Wang et al, 2020; Xu et al, 2015; Zhu et al, 2014). Electrostatic repulsion is also affected by Hofmeister effects: different ions with same valence have significant differences in the ability to screen the surface electric field of colloidal particles, which lead to significant differences in colloid aggregation (Huangfu et al, 2013; Pokhrel et al, 2014; Tian et al, 2014; Vereda et al, 2015; Zhang et al, 2020).…”

Effect of paddy cultivation on the surface electrochemical properties of different‐sized particles of a Gleysol

“…In addition, the phenomenon of flocculation, caused by interactions among soil particles, is the first step necessary for the formation of soil structure. Extensive flocculation experiments have shown interactions between soil colloids and organic matter (Park et al., 2018), Fe/Al (hydr)oxides (West, et al., 2004; Li et al., 2018), as well as with themselves (Lagaly & Ziesmer, 2003; C. Y. Xu et al., 2020), yet little investigation has been conducted on the nanoparticle (NP) sedimentation. Global interest in soil NPs has increased over the past two decades in response to the observation that their specific surface properties deviated markedly from those shown by their macroscopic (bulk) counterparts (Theng & Yuan, 2008).…”