Organo-Bentonite-Coated Interfaces: Interfacial Properties and Cyclic Response
Year: 2023
Journal: Energy & Fuels, Volume 37, 2023-07-06
Authors: Benitez, Marcelo D.; Liu, Qi; Santamarina, J. Carlos
The accumulation of amphiphilic molecules, nanoparticles, or microorganisms at interfaces has important implications for multiphase flow in porous media. We optimize the composition of stable organo-bentonite suspensions to enhance particle adsorption onto the oil–water interface. Then, we use the pendant drop method to explore time-dependent effects on surface tension and the consequences of contraction–expansion cycles. Brownian motion brings organo-bentonite particles to the oil–water interface where they adsorb and accumulate to reduce the apparent interfacial tension in time. The adsorption energy of platy organo-bentonite particles is significantly higher than the adsorption energy of spherical nanoparticles of the same volume. Then, a shell-like interface develops after particle jamming during droplet contraction, and further contraction leads to shell buckling and wrinkle formation (rather than desorption). The shell-like interface experiences an anisotropic stress field and cannot be described by the Young–Laplace equation. The evolution of interfacial tension during contraction and expansion shows strong hysteresis; furthermore, the results suggest that the number of adsorbed particles at the interface increases with the number of cycles. Natural clay nanoparticles can facilitate the development of cost-effective and environmentally friendly alternatives for field-scale applications.
