Mimicking the Behaviors of Oil Contaminated Clays Using Functionalized Silica Nanoparticles

Abstract

Fine sand and clay particles arise naturally in diverse industrial and environmental remediation contexts. Organic compounds for example from oil production or oil spills can adsorb on their surface and influence their oil water interfacial behaviors. To isolate the impact of contamination and mimic contaminated clay behaviors, functionalized silica nanoparticles, with both aliphatic chains and aromatic group on their surface, were synthesized and their interfacial properties at oil-water interfaces were evaluated. The outcomes of this work shed light on the interfacial behaviors of contaminated clays in, for example, oil sands production processes. The interfacial tension between water and bare silica, silylated silica, silylated silica-octyl and silylated silica-anthracene nanoparticles suspension were measured. Factors that influence interfacial tension including nanoparticle concentration, pH and salinity (NaCl and CaCl2) were investigated. While impacts of each of these variables is measurable, the overall impact of silica nanoparticle functionalization on interfacial behaviours is limited relative to bare silica, indicating that the interfacial behaviour of silica nanoparticles is dominated by the properties of the silica substrate. Functionalization does however impact nanoparticle aggregation. Silylated and silylated silica-octyl nanoparticles aggregate in toluene at high concentration.