Interface tension of silica hydroxylated nanoparticle with brine: A combined experimental and molecular dynamics study

Abstract

We have used molecular dynamics simulations to calculate the interfacial tension of hydroxylated SiO(2) nanoparticles under different temperatures and solutions (helium and brine with monovalent and divalent salts). In order to benchmark the atomistic model, quartz SiO(2) interfacial tension was measured based on inverse gas chromatography under He atmosphere. The experimental interfacial tension values for quartz were found between 0.512 and 0.617 N/m. Our calculated results for the interfacial tension of silica nanoparticles within helium atmosphere was 0.676 N/m, which is higher than the value found for the system containing He∕α-quartz (0.478 N/m), but it is similar to the one found for amorphous silica surface. We have also studied the interfacial tension of the nanoparticles in electrolyte aqueous solution for different types and salts concentrations (NaCl, CaCl(2), and MgCl(2)). Our calculations indicate that adsorption properties and salt solutions greatly influence the interfacial tension in an order of CaCl(2) > MgCl(2) > NaCl. This effect is due to the difference in distribution of ions in solution, which modifies the hydration and electrostatic potential of those ions near the nanoparticle.

Nanoparticle effects on the water-oil interfacial tension

“…13 It was found that the different propensity of the ions to distribute on the NPs surface affects the interfacial tension. Ranatunga et al simulated NPs and non-ionic surfactants at the oil-water interface using molecular dynamics.…”

Potential applications of cyclodextrins in enhanced oil recovery

“…Thus, the quartz surfaces used for the calculations were generated by cleaving the bulk quartz material to give (0 0 0 1) surfaces with under-coordinated surface species, e.g. singly coordinated oxygen and three-coordinated silicon atoms following our previous work [35]. Termination of the dangling bonds in surface Si and O atoms with hydroxy groups and protons, respectively, resulted in the formation of the surface silanol groups.…”

“…Â was calculated using Eq. (3)[35][36][37], where H is the maximum droplet height and R the radius of the circle (dashed line) as indicated in the images. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)…”

Improved oil recovery in nanopores: NanoIOR

“…We have obtained the pressure tensor for each atom individually according to the method described by Thompson et al 16 . From the obtained pressure tensor, after its transformation to cylindrical coordinates (as described by Kim et al 22 and Wang et al 23 ), we were able to obtain the interfacial tensions with the Irving-Kirkwood method 24 , as described by de Lara et al 25 . The following equation was used to calculate the interfacial tensions: where γ is the interfacial tension and p ( r ) is the radial component of the pressure tensor.…”