(88f) Adsorption of Acrylic/Sulfonic Acid Copolymer-Coated Iron Oxide Nanoclusters On Silica Microspheres At High Divalent Salinity

Minimizing the adsorption of engineered nanoparticles (NPs) on rock surface is paramount for feasibility of sub-surface applications and environmental fate of NPs. Natural reservoir brines often have high salinity including the presence of significant divalent cations including calcium that lead to strong NP adsorption.  We recently identified a class of acrylic /sulfonic acid copolymer-coated iron oxide (IO) nanoclusters that display enhanced colloidal stability in the presence of divalent cations.  Here, we report a combinatorial approach to study batch adsorption of IO coated with different polymers on silica microsphere models at various salinity and pH.  The isotherms provide the adsorption capacity and equilibrium adsorption constants for various conditions.  We find that a low adsorption capacity from these batch experiments is a necessary condition for successful transport in flow experiments. Thus, in addition to providing the equilibrium adsorption capacity, the batch isotherms also save time for guiding the more laborious/expensive flow experiments.