nanoparticle, clay, swelling, polyethylene glycol
Successful application of nanoparticles is dependent on understanding the mobility, retention, and transport fate of nanoparticles in natural formations. These aspects are greatly influenced by subsurface environmental conditions such as electrolyte type and concentration, temperature, pH and mineral composition of the formation as well as characteristics of the nanoparticle itself such as concentration and surface modifications. Characterizing the effects of surface functionalization and retention of nanoparticles onto clay minerals due to adsorption under subsurface conditions will be necessary for selecting the types of nanoparticles or surface modification to be used as suitable nanosensors or EOR agents. In this study, the effects of surface functionalization through a polyethylene (PEG) coating on 5 nm silica nanoparticle on mobility was evaluated through observations on clay swelling inhibition. Adsorption onto montmorillonite and illite was also investigated. Visual swelling tests were utilized to investigate clay swelling inhibition and ultraviolet-visible (UV-vis) spectroscopy was used to determine the concentration of adsorbed nanoparticles in conditions that are likely to be found in subsurface reservoir environments.