Polymer-functionalized nanoparticles as agents for the in situ remediation of oil-contaminated soils

Abstract

In-situ flushing of chemicals, such as nanoparticle (NP) suspensions, and NP-based Pickering emulsions, is a well-promising method for the remediation of soils and aquifers contaminated with non-aqueous phase liquids (NAPLs) and the enhanced oil recovery from reservoir rocks. Linear and comb-type copolymers were synthesized by combining (i) hydrophilic, anionic monomers like 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and acrylic acid (AA) with (ii) hydrophobic monomers like dodecyl methacrylate (DMA). Moreover, polymer-coated nanoparticles (PNPs) was prepared by post-grafting and surface initiated free radical polymerization (FRP) on commercial silica nanoparticles. Dilute dispersions of polymers and PNPs were mixed with salts (NaCl, CaCl2), their dynamic surface and oil/water interfacial tensions were measured by the pendant drop method, and the wettability of all fluid systems to glass surface was quantified by measuring the contact angle. Oil-in-water Pickering emulsions were prepared by dispersing n-dodecane in polymers and n-decane in PNP-colloid with ultrasound probe, and their stability was evaluated by tracking the phase separation and changes of rheological properties, as functions of time. Furthermore, the most stable polymers and PNP-based dispersions and emulsions were chosen and tested as chemicals for the removal of residual oil from a transparent glass-etched pore network.