Micro-Scale Simulation of Adsorption-Diffusion Behaviors of
Nanoparticles onto Oil/Water Interface
Abstract
A novel, hybrid pore-scale simulation method using Lattice-Boltzmann
(LB) coupled with Langevin-Dynamics (LD) is proposed to investigate the
physics of nanoparticles onto oil/water interface. By the means of the
new LB-LD coupling model, the adsorption and diffusion characterization
of nanoparticles onto oil/water interface are investigated. Moreover, by
introducing interference coefficient and non-equilibrium time, a
modified Langmuir adsorption equation is first established by more
accurately quantifying the adsorption characterization of nanoparticles
and the consequent impacts onto oil/water interfacial tension, of which
the classical Langmuir adsorption equation cannot take account. For a
target representative example of SiO2 nanoparticles, it is observed that
small-size nanofluids with high concentration could accelerate the
adsorption of nanoparticles and therefore help decrease oil/water
interface tension. In addition, both the lateral and longitudinal
diffusion coefficients of nanoparticles into the water phase and onto
oil/water interface are obtained, and of which the underlying mechanisms
are explained in details.